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foundationdb/fdbserver/VersionedBTree.actor.cpp

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/*
* VersionedBTree.actor.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "flow/flow.h"
#include "fdbserver/IVersionedStore.h"
#include "fdbserver/IPager.h"
#include "fdbclient/Tuple.h"
#include "flow/serialize.h"
#include "flow/genericactors.actor.h"
#include "flow/UnitTest.h"
#include "fdbserver/IPager.h"
#include "fdbrpc/IAsyncFile.h"
#include "flow/ActorCollection.h"
#include <map>
#include <vector>
#include "fdbclient/CommitTransaction.h"
#include "fdbserver/IKeyValueStore.h"
#include "fdbserver/DeltaTree.h"
#include <string.h>
#include "flow/actorcompiler.h"
#include <cinttypes>
#include <boost/intrusive/list.hpp>
#define REDWOOD_DEBUG 0
// Only print redwood debug statements for a certain address. Useful in simulation with many redwood processes to reduce
// log size.
#define REDWOOD_DEBUG_ADDR 0
// example addr: "[abcd::4:0:1:4]:1"
#define REDWOOD_DEBUG_ADDR_VAL "";
#define debug_printf_stream stdout
#define debug_printf_always(...) \
{ \
std::string prefix = format("%s %f %04d ", g_network->getLocalAddress().toString().c_str(), now(), __LINE__); \
std::string msg = format(__VA_ARGS__); \
writePrefixedLines(debug_printf_stream, prefix, msg); \
fflush(debug_printf_stream); \
}
#define debug_printf_addr(...) \
{ \
std::string addr = REDWOOD_DEBUG_ADDR_VAL; \
if (!memcmp(addr.c_str(), g_network->getLocalAddress().toString().c_str(), addr.size())) { \
std::string prefix = \
format("%s %f %04d ", g_network->getLocalAddress().toString().c_str(), now(), __LINE__); \
std::string msg = format(__VA_ARGS__); \
writePrefixedLines(debug_printf_stream, prefix, msg); \
fflush(debug_printf_stream); \
} \
}
#define debug_printf_noop(...)
#if defined(NO_INTELLISENSE)
#if REDWOOD_DEBUG
#define debug_printf debug_printf_always
#elif REDWOOD_DEBUG_ADDR
#define debug_printf debug_printf_addr
#else
#define debug_printf debug_printf_noop
#endif
#else
// To get error-checking on debug_printf statements in IDE
#define debug_printf printf
#endif
#define BEACON debug_printf_always("HERE\n")
#define TRACE \
debug_printf_always("%s: %s line %d %s\n", __FUNCTION__, __FILE__, __LINE__, platform::get_backtrace().c_str());
// Writes prefix:line for each line in msg to fout
void writePrefixedLines(FILE* fout, std::string prefix, std::string msg) {
StringRef m = msg;
while (m.size() != 0) {
StringRef line = m.eat("\n");
fprintf(fout, "%s %s\n", prefix.c_str(), line.toString().c_str());
}
}
// Some convenience functions for debugging to stringify various structures
// Classes can add compatibility by either specializing toString<T> or implementing
// std::string toString() const;
template <typename T>
std::string toString(const T& o) {
return o.toString();
}
std::string toString(StringRef s) {
return s.printable();
}
std::string toString(LogicalPageID id) {
if (id == invalidLogicalPageID) {
return "LogicalPageID{invalid}";
}
return format("LogicalPageID{%u}", id);
}
std::string toString(Version v) {
if (v == invalidVersion) {
return "invalidVersion";
}
return format("@%" PRId64, v);
}
std::string toString(bool b) {
return b ? "true" : "false";
}
template <typename T>
std::string toString(const Standalone<T>& s) {
return toString((T)s);
}
template <typename T>
std::string toString(const T* begin, const T* end) {
std::string r = "{";
bool comma = false;
while (begin != end) {
if (comma) {
r += ", ";
} else {
comma = true;
}
r += toString(*begin++);
}
r += "}";
return r;
}
template <typename T>
std::string toString(const std::vector<T>& v) {
return toString(&v.front(), &v.back() + 1);
}
template <typename T>
std::string toString(const VectorRef<T>& v) {
return toString(v.begin(), v.end());
}
template <typename T>
std::string toString(const Optional<T>& o) {
if (o.present()) {
return toString(o.get());
}
return "<not present>";
}
template <typename F, typename S>
std::string toString(const std::pair<F, S>& o) {
return format("{%s, %s}", toString(o.first).c_str(), toString(o.second).c_str());
}
// A FIFO queue of T stored as a linked list of pages.
// Main operations are pop(), pushBack(), pushFront(), and flush().
//
// flush() will ensure all queue pages are written to the pager and move the unflushed
// pushFront()'d records onto the front of the queue, in FIFO order.
//
// pop() will only return records that have been flushed, and pops
// from the front of the queue.
//
// Each page contains some number of T items and a link to the next page and starting position on that page.
// When the queue is flushed, the last page in the chain is ended and linked to a newly allocated
// but not-yet-written-to pageID, which future writes after the flush will write to.
// Items pushed onto the front of the queue are written to a separate linked list until flushed,
// at which point that list becomes the new front of the queue.
//
// The write pattern is designed such that no page is ever expected to be valid after
// being written to or updated but not fsync'd. This is why a new unused page is added
// to the queue, linked to by the last data page, before commit. The new page can't be
// added and filled with data as part of the next commit because that would mean modifying
// the previous tail page to update its next link, which risks corrupting it and losing
// data that was not yet popped if that write is never fsync'd.
//
// Requirements on T
// - must be trivially copyable
// OR have a specialization for FIFOQueueCodec<T>
// OR have the following methods
// // Deserialize from src into *this, return number of bytes from src consumed
// int readFromBytes(const uint8_t *src);
// // Return the size of *this serialized
// int bytesNeeded() const;
// // Serialize *this to dst, return number of bytes written to dst
// int writeToBytes(uint8_t *dst) const;
// - must be supported by toString(object) (see above)
template <typename T, typename Enable = void>
struct FIFOQueueCodec {
static T readFromBytes(const uint8_t* src, int& bytesRead) {
T x;
bytesRead = x.readFromBytes(src);
return x;
}
static int bytesNeeded(const T& x) { return x.bytesNeeded(); }
static int writeToBytes(uint8_t* dst, const T& x) { return x.writeToBytes(dst); }
};
template <typename T>
struct FIFOQueueCodec<T, typename std::enable_if<std::is_trivially_copyable<T>::value>::type> {
static_assert(std::is_trivially_copyable<T>::value);
static T readFromBytes(const uint8_t* src, int& bytesRead) {
bytesRead = sizeof(T);
return *(T*)src;
}
static int bytesNeeded(const T& x) { return sizeof(T); }
static int writeToBytes(uint8_t* dst, const T& x) {
*(T*)dst = x;
return sizeof(T);
}
};
template <typename T, typename Codec = FIFOQueueCodec<T>>
class FIFOQueue {
public:
#pragma pack(push, 1)
struct QueueState {
bool operator==(const QueueState& rhs) const { return memcmp(this, &rhs, sizeof(QueueState)) == 0; }
LogicalPageID headPageID = invalidLogicalPageID;
LogicalPageID tailPageID = invalidLogicalPageID;
uint16_t headOffset;
// Note that there is no tail index because the tail page is always never-before-written and its index will
// start at 0
int64_t numPages;
int64_t numEntries;
std::string toString() const {
return format("{head: %s:%d tail: %s numPages: %" PRId64 " numEntries: %" PRId64 "}",
::toString(headPageID).c_str(),
(int)headOffset,
::toString(tailPageID).c_str(),
numPages,
numEntries);
}
};
#pragma pack(pop)
struct Cursor {
// Queue mode
enum Mode { NONE, POP, READONLY, WRITE };
Mode mode;
// Queue this cursor is accessing
FIFOQueue* queue;
// The current page and pageID being read or written to
LogicalPageID pageID;
Reference<ArenaPage> page;
// The first page ID to be written to the pager, if this cursor has written anything
LogicalPageID firstPageIDWritten;
// Offset after RawPage header in page to next read from or write to
int offset;
// A read cursor will not read this page (or beyond)
LogicalPageID endPageID;
// Page future and corresponding page ID for the expected next page to be used. It may not
// match the current page's next page link because queues can prepended with new front pages.
Future<Reference<ArenaPage>> nextPageReader;
LogicalPageID nextPageID;
// Future that represents all outstanding write operations previously issued
// This exists because writing the queue returns void, not a future
Future<Void> writeOperations;
FlowLock mutex;
Future<Void> killMutex;
Cursor() : mode(NONE) {}
// Initialize a cursor.
void init(FIFOQueue* q = nullptr,
Mode m = NONE,
LogicalPageID initialPageID = invalidLogicalPageID,
int readOffset = 0,
LogicalPageID endPage = invalidLogicalPageID) {
queue = q;
// If the pager gets an error, which includes shutdown, kill the mutex so any waiters can no longer run.
// This avoids having every mutex wait also wait on pagerError.
killMutex = map(ready(queue->pagerError), [=](Void e) {
mutex.kill();
return Void();
});
mode = m;
firstPageIDWritten = invalidLogicalPageID;
offset = readOffset;
endPageID = endPage;
page.clear();
writeOperations = Void();
if (mode == POP || mode == READONLY) {
// If cursor is not pointed at the end page then start loading it.
// The end page will not have been written to disk yet.
pageID = initialPageID;
if (pageID != endPageID) {
startNextPageLoad(pageID);
} else {
nextPageID = invalidLogicalPageID;
}
} else {
pageID = invalidLogicalPageID;
ASSERT(mode == WRITE ||
(initialPageID == invalidLogicalPageID && readOffset == 0 && endPage == invalidLogicalPageID));
}
debug_printf("FIFOQueue::Cursor(%s) initialized\n", toString().c_str());
if (mode == WRITE && initialPageID != invalidLogicalPageID) {
addNewPage(initialPageID, 0, true);
}
}
// Since cursors can have async operations pending which modify their state they can't be copied cleanly
Cursor(const Cursor& other) = delete;
~Cursor() { writeOperations.cancel(); }
// A read cursor can be initialized from a pop cursor
void initReadOnly(const Cursor& c) {
ASSERT(c.mode == READONLY || c.mode == POP);
init(c.queue, READONLY, c.pageID, c.offset, c.endPageID);
}
std::string toString() const {
if (mode == WRITE) {
return format("{WriteCursor %s:%p pos=%s:%d rawEndOffset=%d}",
queue->name.c_str(),
this,
::toString(pageID).c_str(),
offset,
page ? raw()->endOffset : -1);
}
if (mode == POP || mode == READONLY) {
return format("{ReadCursor %s:%p pos=%s:%d rawEndOffset=%d endPage=%s nextPage=%s}",
queue->name.c_str(),
this,
::toString(pageID).c_str(),
offset,
page ? raw()->endOffset : -1,
::toString(endPageID).c_str(),
::toString(nextPageID).c_str());
}
ASSERT(mode == NONE);
return format("{NullCursor=%p}", this);
}
#pragma pack(push, 1)
struct RawPage {
// The next page of the queue after this one
LogicalPageID nextPageID;
// The start offset of the next page
uint16_t nextOffset;
// The end offset of the current page
uint16_t endOffset;
// Get pointer to data after page header
uint8_t* begin() { return (uint8_t*)(this + 1); }
};
#pragma pack(pop)
// Returns true if the mutex cannot be immediately taken.
bool isBusy() { return mutex.activePermits() != 0; }
// Wait for all operations started before now to be ready, which is done by
// obtaining and releasing the mutex.
Future<Void> notBusy() {
return isBusy() ? map(mutex.take(),
[&](Void) {
mutex.release();
return Void();
})
: Void();
}
// Returns true if any items have been written to the last page
bool pendingTailWrites() const { return mode == WRITE && offset != 0; }
RawPage* raw() const { return ((RawPage*)(page->begin())); }
void setNext(LogicalPageID pageID, int offset) {
ASSERT(mode == WRITE);
RawPage* p = raw();
p->nextPageID = pageID;
p->nextOffset = offset;
}
void startNextPageLoad(LogicalPageID id) {
nextPageID = id;
debug_printf(
"FIFOQueue::Cursor(%s) loadPage start id=%s\n", toString().c_str(), ::toString(nextPageID).c_str());
nextPageReader = waitOrError(queue->pager->readPage(nextPageID, true), queue->pagerError);
}
void writePage() {
ASSERT(mode == WRITE);
debug_printf("FIFOQueue::Cursor(%s) writePage\n", toString().c_str());
VALGRIND_MAKE_MEM_DEFINED(raw()->begin(), offset);
VALGRIND_MAKE_MEM_DEFINED(raw()->begin() + offset, queue->dataBytesPerPage - raw()->endOffset);
queue->pager->updatePage(pageID, page);
if (firstPageIDWritten == invalidLogicalPageID) {
firstPageIDWritten = pageID;
}
}
// Link the current page to newPageID:newOffset and then write it to the pager.
// The link destination could be a new page at the end of the queue, or the beginning of
// an existing chain of queue pages.
// If initializeNewPage is true a page buffer will be allocated for the new page and it will be initialized
// as a new tail page.
void addNewPage(LogicalPageID newPageID, int newOffset, bool initializeNewPage) {
ASSERT(mode == WRITE);
ASSERT(newPageID != invalidLogicalPageID);
debug_printf("FIFOQueue::Cursor(%s) Adding page %s init=%d\n",
toString().c_str(),
::toString(newPageID).c_str(),
initializeNewPage);
// Update existing page and write, if it exists
if (page) {
setNext(newPageID, newOffset);
debug_printf("FIFOQueue::Cursor(%s) Linked new page %s:%d\n",
toString().c_str(),
::toString(newPageID).c_str(),
newOffset);
writePage();
}
pageID = newPageID;
offset = newOffset;
if (BUGGIFY) {
// Randomly change the byte limit for queue pages. The min here must be large enough for at least one
// queue item of any type. This change will suddenly make some pages being written to seem overfilled
// but this won't break anything, the next write will just be detected as not fitting and the page will
// end.
queue->dataBytesPerPage = deterministicRandom()->randomInt(
50, queue->pager->getUsablePageSize() - sizeof(typename Cursor::RawPage));
}
if (initializeNewPage) {
debug_printf("FIFOQueue::Cursor(%s) Initializing new page\n", toString().c_str());
page = queue->pager->newPageBuffer();
setNext(0, 0);
auto p = raw();
ASSERT(newOffset == 0);
p->endOffset = 0;
} else {
page.clear();
}
}
// Write item to the next position in the current page or, if it won't fit, add a new page and write it there.
ACTOR static Future<Void> write_impl(Cursor* self, T item) {
ASSERT(self->mode == WRITE);
state bool mustWait = self->isBusy();
state int bytesNeeded = Codec::bytesNeeded(item);
state bool needNewPage =
self->pageID == invalidLogicalPageID || self->offset + bytesNeeded > self->queue->dataBytesPerPage;
debug_printf("FIFOQueue::Cursor(%s) write(%s) mustWait=%d needNewPage=%d\n",
self->toString().c_str(),
::toString(item).c_str(),
mustWait,
needNewPage);
// If we have to wait for the mutex because it's busy, or we need a new page, then wait for the mutex.
if (mustWait || needNewPage) {
wait(self->mutex.take());
// If we had to wait because the mutex was busy, then update needNewPage as another writer
// would have changed the cursor state
// Otherwise, taking the mutex would be immediate so no other writer could have run
if (mustWait) {
needNewPage = self->pageID == invalidLogicalPageID ||
self->offset + bytesNeeded > self->queue->dataBytesPerPage;
}
}
// If we need a new page, add one.
if (needNewPage) {
debug_printf("FIFOQueue::Cursor(%s) write(%s) page is full, adding new page\n",
self->toString().c_str(),
::toString(item).c_str());
LogicalPageID newPageID = wait(self->queue->pager->newPageID());
self->addNewPage(newPageID, 0, true);
++self->queue->numPages;
}
debug_printf(
"FIFOQueue::Cursor(%s) write(%s) writing\n", self->toString().c_str(), ::toString(item).c_str());
auto p = self->raw();
Codec::writeToBytes(p->begin() + self->offset, item);
self->offset += bytesNeeded;
p->endOffset = self->offset;
++self->queue->numEntries;
if (mustWait || needNewPage) {
self->mutex.release();
}
return Void();
}
void write(const T& item) {
// Start the write. It may complete immediately if no IO was being waited on
Future<Void> w = write_impl(this, item);
// If it didn't complete immediately, then store the future in operation
if (!w.isReady()) {
writeOperations = writeOperations && w;
}
}
// If readNext() cannot complete immediately, it will route to here
// The mutex will be taken if locked is false
// The next page will be waited for if load is true
// Only mutex holders will wait on the page read.
ACTOR static Future<Optional<T>> waitThenReadNext(Cursor* self,
Optional<T> upperBound,
bool locked,
bool load) {
// Lock the mutex if it wasn't already
if (!locked) {
debug_printf("FIFOQueue::Cursor(%s) waitThenReadNext locking mutex\n", self->toString().c_str());
wait(self->mutex.take());
}
if (load) {
debug_printf("FIFOQueue::Cursor(%s) waitThenReadNext waiting for page load\n",
self->toString().c_str());
wait(success(self->nextPageReader));
}
Optional<T> result = wait(self->readNext(upperBound, true));
// If this actor instance locked the mutex, then unlock it.
if (!locked) {
debug_printf("FIFOQueue::Cursor(%s) waitThenReadNext unlocking mutex\n", self->toString().c_str());
self->mutex.release();
}
return result;
}
// Read the next item at the cursor (if < upperBound), moving to a new page first if the current page is
// exhausted If locked is true, this call owns the mutex, which would have been locked by readNext() before a
// recursive call
Future<Optional<T>> readNext(const Optional<T>& upperBound = {}, bool locked = false) {
if ((mode != POP && mode != READONLY) || pageID == invalidLogicalPageID || pageID == endPageID) {
debug_printf("FIFOQueue::Cursor(%s) readNext returning nothing\n", toString().c_str());
return Optional<T>();
}
// If we don't own the mutex and it's not available then acquire it
if (!locked && isBusy()) {
return waitThenReadNext(this, upperBound, false, false);
}
// We now know pageID is valid and should be used, but page might not point to it yet
if (!page) {
debug_printf("FIFOQueue::Cursor(%s) loading\n", toString().c_str());
// If the next pageID loading or loaded is not the page we should be reading then restart the load
// nextPageID coud be different because it could be invalid or it could be no longer relevant
// if the previous commit added new pages to the front of the queue.
if (pageID != nextPageID) {
debug_printf("FIFOQueue::Cursor(%s) reloading\n", toString().c_str());
startNextPageLoad(pageID);
}
if (!nextPageReader.isReady()) {
return waitThenReadNext(this, upperBound, locked, true);
}
page = nextPageReader.get();
// Start loading the next page if it's not the end page
auto p = raw();
if (p->nextPageID != endPageID) {
startNextPageLoad(p->nextPageID);
} else {
// Prevent a future next page read from reusing the same result as page would have to be updated
// before the queue would read it again
nextPageID = invalidLogicalPageID;
}
}
auto p = raw();
debug_printf("FIFOQueue::Cursor(%s) readNext reading at current position\n", toString().c_str());
ASSERT(offset < p->endOffset);
int bytesRead;
const T result = Codec::readFromBytes(p->begin() + offset, bytesRead);
if (upperBound.present() && upperBound.get() < result) {
debug_printf("FIFOQueue::Cursor(%s) not popping %s, exceeds upper bound %s\n",
toString().c_str(),
::toString(result).c_str(),
::toString(upperBound.get()).c_str());
return Optional<T>();
}
offset += bytesRead;
if (mode == POP) {
--queue->numEntries;
}
debug_printf("FIFOQueue::Cursor(%s) after read of %s\n", toString().c_str(), ::toString(result).c_str());
ASSERT(offset <= p->endOffset);
// If this page is exhausted, start reading the next page for the next readNext() to use, unless it's the
// tail page
if (offset == p->endOffset) {
debug_printf("FIFOQueue::Cursor(%s) Page exhausted\n", toString().c_str());
LogicalPageID oldPageID = pageID;
pageID = p->nextPageID;
offset = p->nextOffset;
// If pageID isn't the tail page and nextPageID isn't pageID then start loading the next page
if (pageID != endPageID && nextPageID != pageID) {
startNextPageLoad(pageID);
}
if (mode == POP) {
--queue->numPages;
}
page.clear();
debug_printf("FIFOQueue::Cursor(%s) readNext page exhausted, moved to new page\n", toString().c_str());
if (mode == POP) {
// Freeing the old page must happen after advancing the cursor and clearing the page reference
// because freePage() could cause a push onto a queue that causes a newPageID() call which could
// pop() from this very same queue. Queue pages are freed at version 0 because they can be reused
// after the next commit.
queue->pager->freePage(oldPageID, 0);
}
}
debug_printf("FIFOQueue(%s) %s(upperBound=%s) -> %s\n",
queue->name.c_str(),
(mode == POP ? "pop" : "peek"),
::toString(upperBound).c_str(),
::toString(result).c_str());
return Optional<T>(result);
}
};
public:
FIFOQueue() : pager(nullptr) {}
~FIFOQueue() { newTailPage.cancel(); }
FIFOQueue(const FIFOQueue& other) = delete;
void operator=(const FIFOQueue& rhs) = delete;
// Create a new queue at newPageID
void create(IPager2* p, LogicalPageID newPageID, std::string queueName) {
debug_printf("FIFOQueue(%s) create from page %s\n", queueName.c_str(), toString(newPageID).c_str());
pager = p;
pagerError = pager->getError();
name = queueName;
numPages = 1;
numEntries = 0;
dataBytesPerPage = pager->getUsablePageSize() - sizeof(typename Cursor::RawPage);
headReader.init(this, Cursor::POP, newPageID, 0, newPageID);
tailWriter.init(this, Cursor::WRITE, newPageID);
headWriter.init(this, Cursor::WRITE);
newTailPage = invalidLogicalPageID;
debug_printf("FIFOQueue(%s) created\n", queueName.c_str());
}
// Load an existing queue from its queue state
void recover(IPager2* p, const QueueState& qs, std::string queueName) {
debug_printf("FIFOQueue(%s) recover from queue state %s\n", queueName.c_str(), qs.toString().c_str());
pager = p;
pagerError = pager->getError();
name = queueName;
numPages = qs.numPages;
numEntries = qs.numEntries;
dataBytesPerPage = pager->getUsablePageSize() - sizeof(typename Cursor::RawPage);
headReader.init(this, Cursor::POP, qs.headPageID, qs.headOffset, qs.tailPageID);
tailWriter.init(this, Cursor::WRITE, qs.tailPageID);
headWriter.init(this, Cursor::WRITE);
newTailPage = invalidLogicalPageID;
debug_printf("FIFOQueue(%s) recovered\n", queueName.c_str());
}
ACTOR static Future<Standalone<VectorRef<T>>> peekAll_impl(FIFOQueue* self) {
state Standalone<VectorRef<T>> results;
state Cursor c;
c.initReadOnly(self->headReader);
results.reserve(results.arena(), self->numEntries);
loop {
Optional<T> x = wait(c.readNext());
if (!x.present()) {
break;
}
results.push_back(results.arena(), x.get());
}
return results;
}
Future<Standalone<VectorRef<T>>> peekAll() { return peekAll_impl(this); }
ACTOR static Future<Optional<T>> peek_impl(FIFOQueue* self) {
state Cursor c;
c.initReadOnly(self->headReader);
Optional<T> x = wait(c.readNext());
return x;
}
Future<Optional<T>> peek() { return peek_impl(this); }
// Pop the next item on front of queue if it is <= upperBound or if upperBound is not present
Future<Optional<T>> pop(Optional<T> upperBound = {}) { return headReader.readNext(upperBound); }
QueueState getState() const {
QueueState s;
s.headOffset = headReader.offset;
s.headPageID = headReader.pageID;
s.tailPageID = tailWriter.pageID;
s.numEntries = numEntries;
s.numPages = numPages;
debug_printf("FIFOQueue(%s) getState(): %s\n", name.c_str(), s.toString().c_str());
return s;
}
void pushBack(const T& item) {
debug_printf("FIFOQueue(%s) pushBack(%s)\n", name.c_str(), toString(item).c_str());
tailWriter.write(item);
}
void pushFront(const T& item) {
debug_printf("FIFOQueue(%s) pushFront(%s)\n", name.c_str(), toString(item).c_str());
headWriter.write(item);
}
bool isBusy() {
return headWriter.isBusy() || headReader.isBusy() || tailWriter.isBusy() || !newTailPage.isReady();
}
// Wait until all previously started operations on each cursor are done and the new tail page is ready
Future<Void> notBusy() {
auto f = headWriter.notBusy() && headReader.notBusy() && tailWriter.notBusy() && ready(newTailPage);
debug_printf("FIFOQueue(%s) notBusy future ready=%d\n", name.c_str(), f.isReady());
return f;
}
// preFlush() prepares this queue to be flushed to disk, but doesn't actually do it so the queue can still
// be pushed and popped after this operation. It returns whether or not any operations were pending or
// started during execution.
//
// If one or more queues are used by their pager in newPageID() or freePage() operations, then preFlush()
// must be called on each of them inside a loop that runs until each of the preFlush() calls have returned
// false twice in a row.
//
// The reason for all this is that:
// - queue pop() can call pager->freePage() which can call push() on the same or another queue
// - queue push() can call pager->newPageID() which can call pop() on the same or another queue
// This creates a circular dependency with 1 or more queues when those queues are used by the pager
// to manage free page IDs.
ACTOR static Future<bool> preFlush_impl(FIFOQueue* self) {
debug_printf("FIFOQueue(%s) preFlush begin\n", self->name.c_str());
wait(self->notBusy());
// Completion of the pending operations as of the start of notBusy() could have began new operations,
// so see if any work is pending now.
bool workPending = self->isBusy();
if (!workPending) {
// A newly created or flushed queue starts out in a state where its tail page to be written to is empty.
// After pushBack() is called, this is no longer the case and never will be again until the queue is
// flushed. Before the non-empty tail page is written it must be linked to a new empty page for use after
// the next flush. (This is explained more at the top of FIFOQueue but it is because queue pages can only
// be written once because once they contain durable data a second write to link to a new page could corrupt
// the existing data if the subsequent commit never succeeds.)
//
// If the newTailPage future is ready but it's an invalid page and the tail page we are currently pointed to
// has had items added to it, then get a new tail page ID.
if (self->newTailPage.isReady() && self->newTailPage.get() == invalidLogicalPageID &&
self->tailWriter.pendingTailWrites()) {
debug_printf("FIFOQueue(%s) preFlush starting to get new page ID\n", self->name.c_str());
self->newTailPage = self->pager->newPageID();
workPending = true;
}
}
debug_printf("FIFOQueue(%s) preFlush returning %d\n", self->name.c_str(), workPending);
return workPending;
}
Future<bool> preFlush() { return preFlush_impl(this); }
void finishFlush() {
debug_printf("FIFOQueue(%s) finishFlush start\n", name.c_str());
ASSERT(!isBusy());
// If a new tail page was allocated, link the last page of the tail writer to it.
if (newTailPage.get() != invalidLogicalPageID) {
tailWriter.addNewPage(newTailPage.get(), 0, false);
// The flush sequence allocated a page and added it to the queue so increment numPages
++numPages;
// newPage() should be ready immediately since a pageID is being explicitly passed.
ASSERT(!tailWriter.isBusy());
newTailPage = invalidLogicalPageID;
}
// If the headWriter wrote anything, link its tail page to the headReader position and point the headReader
// to the start of the headWriter
if (headWriter.pendingTailWrites()) {
headWriter.addNewPage(headReader.pageID, headReader.offset, false);
headReader.pageID = headWriter.firstPageIDWritten;
headReader.offset = 0;
headReader.page.clear();
}
// Update headReader's end page to the new tail page
headReader.endPageID = tailWriter.pageID;
// Reset the write cursors
tailWriter.init(this, Cursor::WRITE, tailWriter.pageID);
headWriter.init(this, Cursor::WRITE);
debug_printf("FIFOQueue(%s) finishFlush end\n", name.c_str());
}
ACTOR static Future<Void> flush_impl(FIFOQueue* self) {
loop {
bool notDone = wait(self->preFlush());
if (!notDone) {
break;
}
}
self->finishFlush();
return Void();
}
Future<Void> flush() { return flush_impl(this); }
IPager2* pager;
Future<Void> pagerError;
int64_t numPages;
int64_t numEntries;
int dataBytesPerPage;
Cursor headReader;
Cursor tailWriter;
Cursor headWriter;
Future<LogicalPageID> newTailPage;
// For debugging
std::string name;
};
int nextPowerOf2(uint32_t x) {
return 1 << (32 - clz(x - 1));
}
struct RedwoodMetrics {
static constexpr int btreeLevels = 5;
RedwoodMetrics() { clear(); }
void clear() {
memset(this, 0, sizeof(RedwoodMetrics));
for (auto& level : levels) {
level = {};
}
startTime = g_network ? now() : 0;
}
struct Level {
unsigned int pageRead;
unsigned int pageReadExt;
unsigned int pageBuild;
unsigned int pageBuildExt;
unsigned int pageCommitStart;
unsigned int pageModify;
unsigned int pageModifyExt;
unsigned int lazyClearRequeue;
unsigned int lazyClearRequeueExt;
unsigned int lazyClearFree;
unsigned int lazyClearFreeExt;
unsigned int forceUpdate;
unsigned int detachChild;
double buildStoredPct;
double buildFillPct;
unsigned int buildItemCount;
double modifyStoredPct;
double modifyFillPct;
unsigned int modifyItemCount;
};
Level levels[btreeLevels];
unsigned int opSet;
unsigned int opSetKeyBytes;
unsigned int opSetValueBytes;
unsigned int opClear;
unsigned int opClearKey;
unsigned int opCommit;
unsigned int opGet;
unsigned int opGetRange;
unsigned int pagerDiskWrite;
unsigned int pagerDiskRead;
unsigned int pagerRemapFree;
unsigned int pagerRemapCopy;
unsigned int pagerRemapSkip;
unsigned int pagerCacheHit;
unsigned int pagerCacheMiss;
unsigned int pagerProbeHit;
unsigned int pagerProbeMiss;
unsigned int pagerEvictUnhit;
unsigned int pagerEvictFail;
unsigned int btreeLeafPreload;
unsigned int btreeLeafPreloadExt;
// Return number of pages read or written, from cache or disk
unsigned int pageOps() const {
// All page reads are either a cache hit, probe hit, or a disk read
return pagerDiskWrite + pagerDiskRead + pagerCacheHit + pagerProbeHit;
}
double startTime;
Level& level(unsigned int level) {
static Level outOfBound;
if (level == 0 || level > btreeLevels) {
return outOfBound;
}
return levels[level - 1];
}
// This will populate a trace event and/or a string with Redwood metrics.
// The string is a reasonably well formatted page of information
void getFields(TraceEvent* e, std::string* s = nullptr, bool skipZeroes = false) {
std::pair<const char*, unsigned int> metrics[] = { { "BTreePreload", btreeLeafPreload },
{ "BTreePreloadExt", btreeLeafPreloadExt },
{ "", 0 },
{ "OpSet", opSet },
{ "OpSetKeyBytes", opSetKeyBytes },
{ "OpSetValueBytes", opSetValueBytes },
{ "OpClear", opClear },
{ "OpClearKey", opClearKey },
{ "", 0 },
{ "OpGet", opGet },
{ "OpGetRange", opGetRange },
{ "OpCommit", opCommit },
{ "", 0 },
{ "PagerDiskWrite", pagerDiskWrite },
{ "PagerDiskRead", pagerDiskRead },
{ "PagerCacheHit", pagerCacheHit },
{ "PagerCacheMiss", pagerCacheMiss },
{ "", 0 },
{ "PagerProbeHit", pagerProbeHit },
{ "PagerProbeMiss", pagerProbeMiss },
{ "PagerEvictUnhit", pagerEvictUnhit },
{ "PagerEvictFail", pagerEvictFail },
{ "", 0 },
{ "PagerRemapFree", pagerRemapFree },
{ "PagerRemapCopy", pagerRemapCopy },
{ "PagerRemapSkip", pagerRemapSkip } };
double elapsed = now() - startTime;
if (e != nullptr) {
for (auto& m : metrics) {
char c = m.first[0];
if (c != 0 && (!skipZeroes || m.second != 0)) {
e->detail(m.first, m.second);
}
}
}
if (s != nullptr) {
for (auto& m : metrics) {
if (*m.first == '\0') {
*s += "\n";
} else if (!skipZeroes || m.second != 0) {
*s += format("%-15s %-8u %8u/s ", m.first, m.second, int(m.second / elapsed));
}
}
}
for (int i = 0; i < btreeLevels; ++i) {
auto& level = levels[i];
std::pair<const char*, unsigned int> metrics[] = {
{ "PageBuild", level.pageBuild },
{ "PageBuildExt", level.pageBuildExt },
{ "PageModify", level.pageModify },
{ "PageModifyExt", level.pageModifyExt },
{ "", 0 },
{ "PageRead", level.pageRead },
{ "PageReadExt", level.pageReadExt },
{ "PageCommitStart", level.pageCommitStart },
{ "", 0 },
{ "LazyClearInt", level.lazyClearRequeue },
{ "LazyClearIntExt", level.lazyClearRequeueExt },
{ "LazyClear", level.lazyClearFree },
{ "LazyClearExt", level.lazyClearFreeExt },
{ "", 0 },
{ "ForceUpdate", level.forceUpdate },
{ "DetachChild", level.detachChild },
{ "", 0 },
{ "-BldAvgCount", level.pageBuild ? level.buildItemCount / level.pageBuild : 0 },
{ "-BldAvgFillPct", level.pageBuild ? level.buildFillPct / level.pageBuild * 100 : 0 },
{ "-BldAvgStoredPct", level.pageBuild ? level.buildStoredPct / level.pageBuild * 100 : 0 },
{ "", 0 },
{ "-ModAvgCount", level.pageModify ? level.modifyItemCount / level.pageModify : 0 },
{ "-ModAvgFillPct", level.pageModify ? level.modifyFillPct / level.pageModify * 100 : 0 },
{ "-ModAvgStoredPct", level.pageModify ? level.modifyStoredPct / level.pageModify * 100 : 0 },
{ "", 0 },
};
if (e != nullptr) {
for (auto& m : metrics) {
char c = m.first[0];
if (c != 0 && (!skipZeroes || m.second != 0)) {
e->detail(format("L%d%s", i + 1, m.first + (c == '-' ? 1 : 0)), m.second);
}
}
}
if (s != nullptr) {
*s += format("\nLevel %d\n\t", i + 1);
for (auto& m : metrics) {
const char* name = m.first;
bool rate = elapsed != 0;
if (*name == '-') {
++name;
rate = false;
}
if (*name == '\0') {
*s += "\n\t";
} else if (!skipZeroes || m.second != 0) {
*s += format("%-15s %8u %8u/s ", name, m.second, rate ? int(m.second / elapsed) : 0);
}
}
}
}
}
std::string toString(bool clearAfter) {
std::string s;
getFields(nullptr, &s);
if (clearAfter) {
clear();
}
return s;
}
};
// Using a global for Redwood metrics because a single process shouldn't normally have multiple storage engines
RedwoodMetrics g_redwoodMetrics = {};
Future<Void> g_redwoodMetricsActor;
ACTOR Future<Void> redwoodMetricsLogger() {
g_redwoodMetrics.clear();
loop {
wait(delay(SERVER_KNOBS->REDWOOD_LOGGING_INTERVAL));
TraceEvent e("RedwoodMetrics");
double elapsed = now() - g_redwoodMetrics.startTime;
e.detail("Elapsed", elapsed);
g_redwoodMetrics.getFields(&e);
g_redwoodMetrics.clear();
}
}
// Holds an index of recently used objects.
// ObjectType must have the methods
// bool evictable() const; // return true if the entry can be evicted
// Future<Void> onEvictable() const; // ready when entry can be evicted
template <class IndexType, class ObjectType>
class ObjectCache : NonCopyable {
struct Entry : public boost::intrusive::list_base_hook<> {
Entry() : hits(0) {}
IndexType index;
ObjectType item;
int hits;
};
typedef std::unordered_map<IndexType, Entry> CacheT;
typedef boost::intrusive::list<Entry> EvictionOrderT;
public:
ObjectCache(int sizeLimit = 1) : sizeLimit(sizeLimit) {}
void setSizeLimit(int n) {
ASSERT(n > 0);
sizeLimit = n;
}
// Get the object for i if it exists, else return nullptr.
// If the object exists, its eviction order will NOT change as this is not a cache hit.
ObjectType* getIfExists(const IndexType& index) {
auto i = cache.find(index);
if (i != cache.end()) {
++i->second.hits;
++g_redwoodMetrics.pagerProbeHit;
return &i->second.item;
}
++g_redwoodMetrics.pagerProbeMiss;
return nullptr;
}
// Try to evict the item at index from cache
// Returns true if item is evicted or was not present in cache
bool tryEvict(const IndexType& index) {
auto i = cache.find(index);
if (i == cache.end() || !i->second.item.evictable()) {
return false;
}
Entry& toEvict = i->second;
if (toEvict.hits == 0) {
++g_redwoodMetrics.pagerEvictUnhit;
}
evictionOrder.erase(evictionOrder.iterator_to(toEvict));
cache.erase(toEvict.index);
return true;
}
// Get the object for i or create a new one.
// After a get(), the object for i is the last in evictionOrder.
// If noHit is set, do not consider this access to be cache hit if the object is present
// If noMiss is set, do not consider this access to be a cache miss if the object is not present
ObjectType& get(const IndexType& index, bool noHit = false, bool noMiss = false) {
Entry& entry = cache[index];
// If entry is linked into evictionOrder then move it to the back of the order
if (entry.is_linked()) {
if (!noHit) {
++entry.hits;
++g_redwoodMetrics.pagerCacheHit;
// Move the entry to the back of the eviction order
evictionOrder.erase(evictionOrder.iterator_to(entry));
evictionOrder.push_back(entry);
}
} else {
if (!noMiss) {
++g_redwoodMetrics.pagerCacheMiss;
}
// Finish initializing entry
entry.index = index;
entry.hits = 0;
// Insert the newly created Entry at the back of the eviction order
evictionOrder.push_back(entry);
// While the cache is too big, evict the oldest entry until the oldest entry can't be evicted.
while (cache.size() > sizeLimit) {
Entry& toEvict = evictionOrder.front();
// It's critical that we do not evict the item we just added because it would cause the reference
// returned to be invalid. An eviction could happen with a no-hit access to a cache resident page
// that is currently evictable and exists in the oversized portion of the cache eviction order due
// to previously failed evictions.
if (&entry == &toEvict) {
debug_printf("Cannot evict target index %s\n", toString(index).c_str());
break;
}
debug_printf("Trying to evict %s to make room for %s\n",
toString(toEvict.index).c_str(),
toString(index).c_str());
if (!toEvict.item.evictable()) {
evictionOrder.erase(evictionOrder.iterator_to(toEvict));
evictionOrder.push_back(toEvict);
++g_redwoodMetrics.pagerEvictFail;
break;
} else {
if (toEvict.hits == 0) {
++g_redwoodMetrics.pagerEvictUnhit;
}
debug_printf(
"Evicting %s to make room for %s\n", toString(toEvict.index).c_str(), toString(index).c_str());
evictionOrder.pop_front();
cache.erase(toEvict.index);
}
}
}
return entry.item;
}
// Clears the cache, saving the entries, and then waits for eachWaits for each item to be evictable and evicts it.
// The cache should not be Evicts all evictable entries
ACTOR static Future<Void> clear_impl(ObjectCache* self) {
state ObjectCache::CacheT cache;
state EvictionOrderT evictionOrder;
// Swap cache contents to local state vars
// After this, no more entries will be added to or read from these
// structures so we know for sure that no page will become unevictable
// after it is either evictable or onEvictable() is ready.
cache.swap(self->cache);
evictionOrder.swap(self->evictionOrder);
state typename EvictionOrderT::iterator i = evictionOrder.begin();
state typename EvictionOrderT::iterator iEnd = evictionOrder.begin();
while (i != iEnd) {
if (!i->item.evictable()) {
wait(i->item.onEvictable());
}
++i;
}
evictionOrder.clear();
cache.clear();
return Void();
}
Future<Void> clear() {
ASSERT(evictionOrder.size() == cache.size());
return clear_impl(this);
}
int count() const { return evictionOrder.size(); }
private:
int64_t sizeLimit;
CacheT cache;
EvictionOrderT evictionOrder;
};
ACTOR template <class T>
Future<T> forwardError(Future<T> f, Promise<Void> target) {
try {
T x = wait(f);
return x;
} catch (Error& e) {
if (e.code() != error_code_actor_cancelled && target.canBeSet()) {
target.sendError(e);
}
throw e;
}
}
class DWALPagerSnapshot;
// An implementation of IPager2 that supports atomicUpdate() of a page without forcing a change to new page ID.
// It does this internally mapping the original page ID to alternate page IDs by write version.
// The page id remaps are kept in memory and also logged to a "remap queue" which must be reloaded on cold start.
// To prevent the set of remaps from growing unboundedly, once a remap is old enough to be at or before the
// oldest pager version being maintained the remap can be "undone" by popping it from the remap queue,
// copying the alternate page ID's data over top of the original page ID's data, and deleting the remap from memory.
// This process basically describes a "Delayed" Write-Ahead-Log (DWAL) because the remap queue and the newly allocated
// alternate pages it references basically serve as a write ahead log for pages that will eventially be copied
// back to their original location once the original version is no longer needed.
class DWALPager : public IPager2 {
public:
typedef FIFOQueue<LogicalPageID> LogicalPageQueueT;
typedef std::map<Version, LogicalPageID> VersionToPageMapT;
typedef std::unordered_map<LogicalPageID, VersionToPageMapT> PageToVersionedMapT;
#pragma pack(push, 1)
struct DelayedFreePage {
Version version;
LogicalPageID pageID;
bool operator<(const DelayedFreePage& rhs) const { return version < rhs.version; }
std::string toString() const {
return format("DelayedFreePage{%s @%" PRId64 "}", ::toString(pageID).c_str(), version);
}
};
struct RemappedPage {
enum Type { NONE = 'N', REMAP = 'R', FREE = 'F', DETACH = 'D' };
RemappedPage(Version v = invalidVersion,
LogicalPageID o = invalidLogicalPageID,
LogicalPageID n = invalidLogicalPageID)
: version(v), originalPageID(o), newPageID(n) {}
Version version;
LogicalPageID originalPageID;
LogicalPageID newPageID;
static Type getTypeOf(LogicalPageID newPageID) {
if (newPageID == invalidLogicalPageID) {
return FREE;
}
if (newPageID == 0) {
return DETACH;
}
return REMAP;
}
Type getType() const { return getTypeOf(newPageID); }
bool operator<(const RemappedPage& rhs) const { return version < rhs.version; }
std::string toString() const {
return format("RemappedPage(%c: %s -> %s %s}",
getType(),
::toString(originalPageID).c_str(),
::toString(newPageID).c_str(),
::toString(version).c_str());
}
};
#pragma pack(pop)
typedef FIFOQueue<DelayedFreePage> DelayedFreePageQueueT;
typedef FIFOQueue<RemappedPage> RemapQueueT;
// If the file already exists, pageSize might be different than desiredPageSize
// Use pageCacheSizeBytes == 0 to use default from flow knobs
// If filename is empty, the pager will exist only in memory and once the cache is full writes will fail.
DWALPager(int desiredPageSize,
std::string filename,
int64_t pageCacheSizeBytes,
Version remapCleanupWindow,
bool memoryOnly = false)
: desiredPageSize(desiredPageSize), filename(filename), pHeader(nullptr), pageCacheBytes(pageCacheSizeBytes),
memoryOnly(memoryOnly), remapCleanupWindow(remapCleanupWindow) {
if (!g_redwoodMetricsActor.isValid()) {
g_redwoodMetricsActor = redwoodMetricsLogger();
}
commitFuture = Void();
recoverFuture = forwardError(recover(this), errorPromise);
}
void setPageSize(int size) {
logicalPageSize = size;
// Physical page size is the total size of the smallest number of physical blocks needed to store
// logicalPageSize bytes
int blocks = 1 + ((logicalPageSize - 1) / smallestPhysicalBlock);
physicalPageSize = blocks * smallestPhysicalBlock;
if (pHeader != nullptr) {
pHeader->pageSize = logicalPageSize;
}
pageCache.setSizeLimit(1 + ((pageCacheBytes - 1) / physicalPageSize));
}
void updateCommittedHeader() {
memcpy(lastCommittedHeaderPage->mutate(), headerPage->begin(), smallestPhysicalBlock);
}
ACTOR static Future<Void> recover(DWALPager* self) {
ASSERT(!self->recoverFuture.isValid());
state bool exists = false;
if (!self->memoryOnly) {
int64_t flags = IAsyncFile::OPEN_UNCACHED | IAsyncFile::OPEN_UNBUFFERED | IAsyncFile::OPEN_READWRITE |
IAsyncFile::OPEN_LOCK;
exists = fileExists(self->filename);
if (!exists) {
flags |= IAsyncFile::OPEN_ATOMIC_WRITE_AND_CREATE | IAsyncFile::OPEN_CREATE;
}
wait(store(self->pageFile, IAsyncFileSystem::filesystem()->open(self->filename, flags, 0644)));
}
// Header page is always treated as having a page size of smallestPhysicalBlock
self->setPageSize(smallestPhysicalBlock);
self->lastCommittedHeaderPage = self->newPageBuffer();
self->pLastCommittedHeader = (Header*)self->lastCommittedHeaderPage->begin();
state int64_t fileSize = 0;
if (exists) {
wait(store(fileSize, self->pageFile->size()));
}
debug_printf(
"DWALPager(%s) recover exists=%d fileSize=%" PRId64 "\n", self->filename.c_str(), exists, fileSize);
// TODO: If the file exists but appears to never have been successfully committed is this an error or
// should recovery proceed with a new pager instance?
// If there are at least 2 pages then try to recover the existing file
if (exists && fileSize >= (self->smallestPhysicalBlock * 2)) {
debug_printf("DWALPager(%s) recovering using existing file\n", self->filename.c_str());
state bool recoveredHeader = false;
// Read physical page 0 directly
wait(store(self->headerPage, self->readHeaderPage(self, 0)));
// If the checksum fails for the header page, try to recover committed header backup from page 1
if (!self->headerPage->verifyChecksum(0)) {
TraceEvent(SevWarn, "DWALPagerRecoveringHeader").detail("Filename", self->filename);
wait(store(self->headerPage, self->readHeaderPage(self, 1)));
if (!self->headerPage->verifyChecksum(1)) {
if (g_network->isSimulated()) {
// TODO: Detect if process is being restarted and only throw injected if so?
throw io_error().asInjectedFault();
}
Error e = checksum_failed();
TraceEvent(SevError, "DWALPagerRecoveryFailed").detail("Filename", self->filename).error(e);
throw e;
}
recoveredHeader = true;
}
self->pHeader = (Header*)self->headerPage->begin();
if (self->pHeader->formatVersion != Header::FORMAT_VERSION) {
Error e = internal_error(); // TODO: Something better?
TraceEvent(SevError, "DWALPagerRecoveryFailedWrongVersion")
.detail("Filename", self->filename)
.detail("Version", self->pHeader->formatVersion)
.detail("ExpectedVersion", Header::FORMAT_VERSION)
.error(e);
throw e;
}
self->setPageSize(self->pHeader->pageSize);
if (self->logicalPageSize != self->desiredPageSize) {
TraceEvent(SevWarn, "DWALPagerPageSizeNotDesired")
.detail("Filename", self->filename)
.detail("ExistingPageSize", self->logicalPageSize)
.detail("DesiredPageSize", self->desiredPageSize);
}
self->freeList.recover(self, self->pHeader->freeList, "FreeListRecovered");
self->delayedFreeList.recover(self, self->pHeader->delayedFreeList, "DelayedFreeListRecovered");
self->remapQueue.recover(self, self->pHeader->remapQueue, "RemapQueueRecovered");
Standalone<VectorRef<RemappedPage>> remaps = wait(self->remapQueue.peekAll());
for (auto& r : remaps) {
self->remappedPages[r.originalPageID][r.version] = r.newPageID;
}
// If the header was recovered from the backup at Page 1 then write and sync it to Page 0 before continuing.
// If this fails, the backup header is still in tact for the next recovery attempt.
if (recoveredHeader) {
// Write the header to page 0
wait(self->writeHeaderPage(0, self->headerPage));
// Wait for all outstanding writes to complete
wait(self->operations.signalAndCollapse());
// Sync header
wait(self->pageFile->sync());
debug_printf("DWALPager(%s) Header recovery complete.\n", self->filename.c_str());
}
// Update the last committed header with the one that was recovered (which is the last known committed
// header)
self->updateCommittedHeader();
self->addLatestSnapshot();
self->remapCleanupFuture = remapCleanup(self);
} else {
// Note: If the file contains less than 2 pages but more than 0 bytes then the pager was never successfully
// committed. A new pager will be created in its place.
// TODO: Is the right behavior?
debug_printf("DWALPager(%s) creating new pager\n", self->filename.c_str());
self->headerPage = self->newPageBuffer();
self->pHeader = (Header*)self->headerPage->begin();
// Now that the header page has been allocated, set page size to desired
self->setPageSize(self->desiredPageSize);
// Write new header using desiredPageSize
self->pHeader->formatVersion = Header::FORMAT_VERSION;
self->pHeader->committedVersion = 1;
self->pHeader->oldestVersion = 1;
// No meta key until a user sets one and commits
self->pHeader->setMetaKey(Key());
// There are 2 reserved pages:
// Page 0 - header
// Page 1 - header backup
self->pHeader->pageCount = 2;
// Create queues
self->freeList.create(self, self->newLastPageID(), "FreeList");
self->delayedFreeList.create(self, self->newLastPageID(), "DelayedFreeList");
self->remapQueue.create(self, self->newLastPageID(), "RemapQueue");
// The first commit() below will flush the queues and update the queue states in the header,
// but since the queues will not be used between now and then their states will not change.
// In order to populate lastCommittedHeader, update the header now with the queue states.
self->pHeader->freeList = self->freeList.getState();
self->pHeader->delayedFreeList = self->delayedFreeList.getState();
self->pHeader->remapQueue = self->remapQueue.getState();
// Set remaining header bytes to \xff
memset(self->headerPage->mutate() + self->pHeader->size(),
0xff,
self->headerPage->size() - self->pHeader->size());
// Since there is no previously committed header use the initial header for the initial commit.
self->updateCommittedHeader();
self->remapCleanupFuture = Void();
wait(self->commit());
}
debug_printf("DWALPager(%s) recovered. committedVersion=%" PRId64 " logicalPageSize=%d physicalPageSize=%d\n",
self->filename.c_str(),
self->pHeader->committedVersion,
self->logicalPageSize,
self->physicalPageSize);
return Void();
}
Reference<ArenaPage> newPageBuffer() override {
return Reference<ArenaPage>(new ArenaPage(logicalPageSize, physicalPageSize));
}
// Returns the usable size of pages returned by the pager (i.e. the size of the page that isn't pager overhead).
// For a given pager instance, separate calls to this function must return the same value.
// TODO: This is abstraction breaking. This should probably be stored as a member, calculated once on construction
// by creating an ArenaPage and getting its usable size.
int getUsablePageSize() const override { return logicalPageSize - sizeof(ArenaPage::Checksum); }
// Get a new, previously available page ID. The page will be considered in-use after the next commit
// regardless of whether or not it was written to, until it is returned to the pager via freePage()
ACTOR static Future<LogicalPageID> newPageID_impl(DWALPager* self) {
// First try the free list
Optional<LogicalPageID> freePageID = wait(self->freeList.pop());
if (freePageID.present()) {
debug_printf("DWALPager(%s) newPageID() returning %s from free list\n",
self->filename.c_str(),
toString(freePageID.get()).c_str());
return freePageID.get();
}
// Try to reuse pages up to the earlier of the oldest version set by the user or the oldest snapshot still in
// the snapshots list
ASSERT(!self->snapshots.empty());
Optional<DelayedFreePage> delayedFreePageID =
wait(self->delayedFreeList.pop(DelayedFreePage{ self->effectiveOldestVersion(), 0 }));
if (delayedFreePageID.present()) {
debug_printf("DWALPager(%s) newPageID() returning %s from delayed free list\n",
self->filename.c_str(),
toString(delayedFreePageID.get()).c_str());
return delayedFreePageID.get().pageID;
}
// Lastly, add a new page to the pager
LogicalPageID id = self->newLastPageID();
debug_printf(
"DWALPager(%s) newPageID() returning %s at end of file\n", self->filename.c_str(), toString(id).c_str());
return id;
};
// Grow the pager file by pone page and return it
LogicalPageID newLastPageID() {
LogicalPageID id = pHeader->pageCount;
++pHeader->pageCount;
return id;
}
Future<LogicalPageID> newPageID() override { return newPageID_impl(this); }
Future<Void> writePhysicalPage(PhysicalPageID pageID, Reference<ArenaPage> page, bool header = false) {
debug_printf("DWALPager(%s) op=%s %s ptr=%p\n",
filename.c_str(),
(header ? "writePhysicalHeader" : "writePhysical"),
toString(pageID).c_str(),
page->begin());
++g_redwoodMetrics.pagerDiskWrite;
VALGRIND_MAKE_MEM_DEFINED(page->begin(), page->size());
page->updateChecksum(pageID);
if (memoryOnly) {
return Void();
}
// Note: Not using forwardError here so a write error won't be discovered until commit time.
int blockSize = header ? smallestPhysicalBlock : physicalPageSize;
Future<Void> f =
holdWhile(page, map(pageFile->write(page->begin(), blockSize, (int64_t)pageID * blockSize), [=](Void) {
debug_printf("DWALPager(%s) op=%s %s ptr=%p\n",
filename.c_str(),
(header ? "writePhysicalHeaderComplete" : "writePhysicalComplete"),
toString(pageID).c_str(),
page->begin());
return Void();
}));
operations.add(f);
return f;
}
Future<Void> writeHeaderPage(PhysicalPageID pageID, Reference<ArenaPage> page) {
return writePhysicalPage(pageID, page, true);
}
void updatePage(LogicalPageID pageID, Reference<ArenaPage> data) override {
// Get the cache entry for this page, without counting it as a cache hit as we're replacing its contents now
// or as a cache miss because there is no benefit to the page already being in cache
PageCacheEntry& cacheEntry = pageCache.get(pageID, true, true);
debug_printf("DWALPager(%s) op=write %s cached=%d reading=%d writing=%d\n",
filename.c_str(),
toString(pageID).c_str(),
cacheEntry.initialized(),
cacheEntry.initialized() && cacheEntry.reading(),
cacheEntry.initialized() && cacheEntry.writing());
// If the page is still being read then it's not also being written because a write places
// the new content into readFuture when the write is launched, not when it is completed.
// Read/write ordering is being enforced so waiting readers will not see the new write. This
// is necessary for remap erasure to work correctly since the oldest version of a page, located
// at the original page ID, could have a pending read when that version is expired (after which
// future reads of the version are not allowed) and the write of the next newest version over top
// of the original page begins.
if (!cacheEntry.initialized()) {
cacheEntry.writeFuture = writePhysicalPage(pageID, data);
} else if (cacheEntry.reading()) {
// Wait for the read to finish, then start the write.
cacheEntry.writeFuture = map(success(cacheEntry.readFuture), [=](Void) {
writePhysicalPage(pageID, data);
return Void();
});
}
// If the page is being written, wait for this write before issuing the new write to ensure the
// writes happen in the correct order
else if (cacheEntry.writing()) {
cacheEntry.writeFuture = map(cacheEntry.writeFuture, [=](Void) {
writePhysicalPage(pageID, data);
return Void();
});
} else {
cacheEntry.writeFuture = writePhysicalPage(pageID, data);
}
// Always update the page contents immediately regardless of what happened above.
cacheEntry.readFuture = data;
}
Future<LogicalPageID> atomicUpdatePage(LogicalPageID pageID, Reference<ArenaPage> data, Version v) override {
debug_printf("DWALPager(%s) op=writeAtomic %s @%" PRId64 "\n", filename.c_str(), toString(pageID).c_str(), v);
Future<LogicalPageID> f = map(newPageID(), [=](LogicalPageID newPageID) {
updatePage(newPageID, data);
// TODO: Possibly limit size of remap queue since it must be recovered on cold start
RemappedPage r{ v, pageID, newPageID };
remapQueue.pushBack(r);
remappedPages[pageID][v] = newPageID;
debug_printf("DWALPager(%s) pushed %s\n", filename.c_str(), RemappedPage(r).toString().c_str());
return pageID;
});
// No need for forwardError here because newPageID() is already wrapped in forwardError
return f;
}
void freeUnmappedPage(LogicalPageID pageID, Version v) {
// If v is older than the oldest version still readable then mark pageID as free as of the next commit
if (v < effectiveOldestVersion()) {
debug_printf("DWALPager(%s) op=freeNow %s @%" PRId64 " oldestVersion=%" PRId64 "\n",
filename.c_str(),
toString(pageID).c_str(),
v,
pLastCommittedHeader->oldestVersion);
freeList.pushBack(pageID);
} else {
// Otherwise add it to the delayed free list
debug_printf("DWALPager(%s) op=freeLater %s @%" PRId64 " oldestVersion=%" PRId64 "\n",
filename.c_str(),
toString(pageID).c_str(),
v,
pLastCommittedHeader->oldestVersion);
delayedFreeList.pushBack({ v, pageID });
}
}
LogicalPageID detachRemappedPage(LogicalPageID pageID, Version v) override {
auto i = remappedPages.find(pageID);
if (i == remappedPages.end()) {
// Page is not remapped
return invalidLogicalPageID;
}
// Get the page that id was most recently remapped to
auto iLast = i->second.rbegin();
LogicalPageID newID = iLast->second;
ASSERT(RemappedPage::getTypeOf(newID) == RemappedPage::REMAP);
// If the last change remap was also at v then change the remap to a delete, as it's essentially
// the same as the original page being deleted at that version and newID being used from then on.
if (iLast->first == v) {
debug_printf("DWALPager(%s) op=detachDelete originalID=%s newID=%s @%" PRId64 " oldestVersion=%" PRId64
"\n",
filename.c_str(),
toString(pageID).c_str(),
toString(newID).c_str(),
v,
pLastCommittedHeader->oldestVersion);
iLast->second = invalidLogicalPageID;
remapQueue.pushBack(RemappedPage{ v, pageID, invalidLogicalPageID });
} else {
debug_printf("DWALPager(%s) op=detach originalID=%s newID=%s @%" PRId64 " oldestVersion=%" PRId64 "\n",
filename.c_str(),
toString(pageID).c_str(),
toString(newID).c_str(),
v,
pLastCommittedHeader->oldestVersion);
// Mark id as converted to its last remapped location as of v
i->second[v] = 0;
remapQueue.pushBack(RemappedPage{ v, pageID, 0 });
}
return newID;
}
void freePage(LogicalPageID pageID, Version v) override {
// If pageID has been remapped, then it can't be freed until all existing remaps for that page have been undone,
// so queue it for later deletion
auto i = remappedPages.find(pageID);
if (i != remappedPages.end()) {
debug_printf("DWALPager(%s) op=freeRemapped %s @%" PRId64 " oldestVersion=%" PRId64 "\n",
filename.c_str(),
toString(pageID).c_str(),
v,
pLastCommittedHeader->oldestVersion);
remapQueue.pushBack(RemappedPage{ v, pageID, invalidLogicalPageID });
i->second[v] = invalidLogicalPageID;
return;
}
freeUnmappedPage(pageID, v);
};
// Read a physical page from the page file. Note that header pages use a page size of smallestPhysicalBlock
// If the user chosen physical page size is larger, then there will be a gap of unused space after the header pages
// and before the user-chosen sized pages.
ACTOR static Future<Reference<ArenaPage>> readPhysicalPage(DWALPager* self,
PhysicalPageID pageID,
bool header = false) {
ASSERT(!self->memoryOnly);
++g_redwoodMetrics.pagerDiskRead;
if (g_network->getCurrentTask() > TaskPriority::DiskRead) {
wait(delay(0, TaskPriority::DiskRead));
}
state Reference<ArenaPage> page =
header ? Reference<ArenaPage>(new ArenaPage(smallestPhysicalBlock, smallestPhysicalBlock))
: self->newPageBuffer();
debug_printf("DWALPager(%s) op=readPhysicalStart %s ptr=%p\n",
self->filename.c_str(),
toString(pageID).c_str(),
page->begin());
int blockSize = header ? smallestPhysicalBlock : self->physicalPageSize;
// TODO: Could a dispatched read try to write to page after it has been destroyed if this actor is cancelled?
int readBytes = wait(self->pageFile->read(page->mutate(), blockSize, (int64_t)pageID * blockSize));
debug_printf("DWALPager(%s) op=readPhysicalComplete %s ptr=%p bytes=%d\n",
self->filename.c_str(),
toString(pageID).c_str(),
page->begin(),
readBytes);
// Header reads are checked explicitly during recovery
if (!header) {
if (!page->verifyChecksum(pageID)) {
debug_printf(
"DWALPager(%s) checksum failed for %s\n", self->filename.c_str(), toString(pageID).c_str());
Error e = checksum_failed();
TraceEvent(SevError, "DWALPagerChecksumFailed")
.detail("Filename", self->filename.c_str())
.detail("PageID", pageID)
.detail("PageSize", self->physicalPageSize)
.detail("Offset", pageID * self->physicalPageSize)
.detail("CalculatedChecksum", page->calculateChecksum(pageID))
.detail("ChecksumInPage", page->getChecksum())
.error(e);
ASSERT(false);
throw e;
}
}
return page;
}
static Future<Reference<ArenaPage>> readHeaderPage(DWALPager* self, PhysicalPageID pageID) {
return readPhysicalPage(self, pageID, true);
}
bool tryEvictPage(LogicalPageID logicalID, Version v) {
PhysicalPageID physicalID = getPhysicalPageID(logicalID, v);
return pageCache.tryEvict(physicalID);
}
// Reads the most recent version of pageID, either previously committed or written using updatePage()
// in the current commit
// If cacheable is false then if fromCache is valid it will be set to true if the page is from cache, otherwise
// false. If cacheable is true, fromCache is ignored as the result is automatically from cache by virtue of being
// cacheable.
Future<Reference<ArenaPage>> readPage(LogicalPageID pageID,
bool cacheable,
bool noHit = false,
bool* fromCache = nullptr) override {
// Use cached page if present, without triggering a cache hit.
// Otherwise, read the page and return it but don't add it to the cache
if (!cacheable) {
debug_printf("DWALPager(%s) op=readUncached %s\n", filename.c_str(), toString(pageID).c_str());
PageCacheEntry* pCacheEntry = pageCache.getIfExists(pageID);
if (fromCache != nullptr) {
*fromCache = pCacheEntry != nullptr;
}
if (pCacheEntry != nullptr) {
debug_printf("DWALPager(%s) op=readUncachedHit %s\n", filename.c_str(), toString(pageID).c_str());
return pCacheEntry->readFuture;
}
debug_printf("DWALPager(%s) op=readUncachedMiss %s\n", filename.c_str(), toString(pageID).c_str());
return forwardError(readPhysicalPage(this, (PhysicalPageID)pageID), errorPromise);
}
PageCacheEntry& cacheEntry = pageCache.get(pageID, noHit);
debug_printf("DWALPager(%s) op=read %s cached=%d reading=%d writing=%d noHit=%d\n",
filename.c_str(),
toString(pageID).c_str(),
cacheEntry.initialized(),
cacheEntry.initialized() && cacheEntry.reading(),
cacheEntry.initialized() && cacheEntry.writing(),
noHit);
if (!cacheEntry.initialized()) {
debug_printf("DWALPager(%s) issuing actual read of %s\n", filename.c_str(), toString(pageID).c_str());
cacheEntry.readFuture = forwardError(readPhysicalPage(this, (PhysicalPageID)pageID), errorPromise);
cacheEntry.writeFuture = Void();
}
return cacheEntry.readFuture;
}
PhysicalPageID getPhysicalPageID(LogicalPageID pageID, Version v) {
auto i = remappedPages.find(pageID);
if (i != remappedPages.end()) {
auto j = i->second.upper_bound(v);
if (j != i->second.begin()) {
--j;
debug_printf("DWALPager(%s) op=lookupRemapped %s @%" PRId64 " -> %s\n",
filename.c_str(),
toString(pageID).c_str(),
v,
toString(j->second).c_str());
pageID = j->second;
ASSERT(pageID != invalidLogicalPageID);
}
} else {
debug_printf("DWALPager(%s) op=lookupNotRemapped %s @%" PRId64 " (not remapped)\n",
filename.c_str(),
toString(pageID).c_str(),
v);
}
return (PhysicalPageID)pageID;
}
Future<Reference<ArenaPage>> readPageAtVersion(LogicalPageID logicalID,
Version v,
bool cacheable,
bool noHit,
bool* fromCache) {
PhysicalPageID physicalID = getPhysicalPageID(logicalID, v);
return readPage(physicalID, cacheable, noHit, fromCache);
}
// Get snapshot as of the most recent committed version of the pager
Reference<IPagerSnapshot> getReadSnapshot(Version v) override;
void addLatestSnapshot();
// Set the pending oldest versiont to keep as of the next commit
void setOldestVersion(Version v) override {
ASSERT(v >= pHeader->oldestVersion);
ASSERT(v <= pHeader->committedVersion);
pHeader->oldestVersion = v;
expireSnapshots(v);
};
// Get the oldest *readable* version, which is not the same as the oldest retained version as the version
// returned could have been set as the oldest version in the pending commit
Version getOldestVersion() const override { return pHeader->oldestVersion; };
// Calculate the *effective* oldest version, which can be older than the one set in the last commit since we
// are allowing active snapshots to temporarily delay page reuse.
Version effectiveOldestVersion() {
return std::min(pLastCommittedHeader->oldestVersion, snapshots.front().version);
}
ACTOR static Future<Void> removeRemapEntry(DWALPager* self, RemappedPage p, Version oldestRetainedVersion) {
// Get iterator to the versioned page map entry for the original page
state PageToVersionedMapT::iterator iPageMapPair = self->remappedPages.find(p.originalPageID);
// The iterator must be valid and not empty and its first page map entry must match p's version
ASSERT(iPageMapPair != self->remappedPages.end());
ASSERT(!iPageMapPair->second.empty());
state VersionToPageMapT::iterator iVersionPagePair = iPageMapPair->second.find(p.version);
ASSERT(iVersionPagePair != iPageMapPair->second.end());
RemappedPage::Type firstType = p.getType();
state RemappedPage::Type secondType;
bool secondAfterOldestRetainedVersion = false;
state bool deleteAtSameVersion = false;
if (p.newPageID == iVersionPagePair->second) {
auto nextEntry = iVersionPagePair;
++nextEntry;
if (nextEntry == iPageMapPair->second.end()) {
secondType = RemappedPage::NONE;
} else {
secondType = RemappedPage::getTypeOf(nextEntry->second);
secondAfterOldestRetainedVersion = nextEntry->first > oldestRetainedVersion;
}
} else {
ASSERT(iVersionPagePair->second == invalidLogicalPageID);
secondType = RemappedPage::FREE;
deleteAtSameVersion = true;
}
ASSERT(firstType == RemappedPage::REMAP || secondType == RemappedPage::NONE);
// Scenarios and actions to take:
//
// The first letter (firstType) is the type of the entry just popped from the remap queue.
// The second letter (secondType) is the type of the next item in the queue for the same
// original page ID, if present. If not present, secondType will be NONE.
//
// Since the next item can be arbitrarily ahead in the queue, secondType is determined by
// looking at the remappedPages structure.
//
// R == Remap F == Free D == Detach | == oldestRetaineedVersion
//
// R R | free new ID
// R F | free new ID if R and D are at different versions
// R D | do nothing
// R | R copy new to original ID, free new ID
// R | F copy new to original ID, free new ID
// R | D copy new to original ID
// R | copy new to original ID, free new ID
// F | free original ID
// D | free original ID
//
// Note that
//
// Special case: Page is detached while it is being read in remapCopyAndFree()
// Initial state: R |
// Start remapCopyAndFree(), intending to copy new, ID to originalID and free newID
// New state: R | D
// Read of newID completes.
// Copy new contents over original, do NOT free new ID
// Later popped state: D |
// free original ID
//
state bool freeNewID =
(firstType == RemappedPage::REMAP && secondType != RemappedPage::DETACH && !deleteAtSameVersion);
state bool copyNewToOriginal = (firstType == RemappedPage::REMAP &&
(secondAfterOldestRetainedVersion || secondType == RemappedPage::NONE));
state bool freeOriginalID = (firstType == RemappedPage::FREE || firstType == RemappedPage::DETACH);
debug_printf("DWALPager(%s) remapCleanup %s secondType=%c mapEntry=%s oldestRetainedVersion=%" PRId64 " \n",
self->filename.c_str(),
p.toString().c_str(),
secondType,
::toString(*iVersionPagePair).c_str(),
oldestRetainedVersion);
if (copyNewToOriginal) {
if (g_network->isSimulated()) {
ASSERT(self->remapDestinationsSimOnly.count(p.originalPageID) == 0);
self->remapDestinationsSimOnly.insert(p.originalPageID);
}
debug_printf("DWALPager(%s) remapCleanup copy %s\n", self->filename.c_str(), p.toString().c_str());
// Read the data from the page that the original was mapped to
Reference<ArenaPage> data = wait(self->readPage(p.newPageID, false, true));
// Write the data to the original page so it can be read using its original pageID
self->updatePage(p.originalPageID, data);
++g_redwoodMetrics.pagerRemapCopy;
} else if (firstType == RemappedPage::REMAP) {
++g_redwoodMetrics.pagerRemapSkip;
}
// Now that the page contents have been copied to the original page, if the corresponding map entry
// represented the remap and there wasn't a delete later in the queue at p for the same version then
// erase the entry.
if (!deleteAtSameVersion) {
debug_printf(
"DWALPager(%s) remapCleanup deleting map entry %s\n", self->filename.c_str(), p.toString().c_str());
// Erase the entry and set iVersionPagePair to the next entry or end
iVersionPagePair = iPageMapPair->second.erase(iVersionPagePair);
// If the map is now empty, delete it
if (iPageMapPair->second.empty()) {
debug_printf(
"DWALPager(%s) remapCleanup deleting empty map %s\n", self->filename.c_str(), p.toString().c_str());
self->remappedPages.erase(iPageMapPair);
} else if (freeNewID && secondType == RemappedPage::NONE &&
iVersionPagePair != iPageMapPair->second.end() &&
RemappedPage::getTypeOf(iVersionPagePair->second) == RemappedPage::DETACH) {
// If we intend to free the new ID and there was no map entry, one could have been added during the wait
// above. If so, and if it was a detach operation, then we can't free the new page ID as its lifetime
// will be managed by the client starting at some later version.
freeNewID = false;
}
}
if (freeNewID) {
debug_printf("DWALPager(%s) remapCleanup freeNew %s\n", self->filename.c_str(), p.toString().c_str());
self->freeUnmappedPage(p.newPageID, 0);
++g_redwoodMetrics.pagerRemapFree;
}
if (freeOriginalID) {
debug_printf("DWALPager(%s) remapCleanup freeOriginal %s\n", self->filename.c_str(), p.toString().c_str());
self->freeUnmappedPage(p.originalPageID, 0);
++g_redwoodMetrics.pagerRemapFree;
}
return Void();
}
ACTOR static Future<Void> remapCleanup(DWALPager* self) {
state ActorCollection tasks(true);
state Promise<Void> signal;
tasks.add(signal.getFuture());
self->remapCleanupStop = false;
// The oldest retained version cannot change during the cleanup run as this would allow multiple read/copy
// operations with the same original page ID destination to be started and they could complete out of order.
state Version oldestRetainedVersion = self->effectiveOldestVersion();
// Cutoff is the version we can pop to
state RemappedPage cutoff(oldestRetainedVersion - self->remapCleanupWindow);
// Minimum version we must pop to before obeying stop command.
state Version minStopVersion =
cutoff.version - (BUGGIFY ? deterministicRandom()->randomInt(0, 10)
: (self->remapCleanupWindow * SERVER_KNOBS->REDWOOD_REMAP_CLEANUP_LAG));
self->remapDestinationsSimOnly.clear();
state int sinceYield = 0;
loop {
state Optional<RemappedPage> p = wait(self->remapQueue.pop(cutoff));
debug_printf("DWALPager(%s) remapCleanup popped %s\n", self->filename.c_str(), ::toString(p).c_str());
// Stop if we have reached the cutoff version, which is the start of the cleanup coalescing window
if (!p.present()) {
break;
}
Future<Void> task = removeRemapEntry(self, p.get(), oldestRetainedVersion);
if (!task.isReady()) {
tasks.add(task);
}
// If the stop flag is set and we've reached the minimum stop version according the the allowed lag then
// stop.
if (self->remapCleanupStop && p.get().version >= minStopVersion) {
break;
}
if (++sinceYield >= 100) {
sinceYield = 0;
wait(yield());
}
}
debug_printf("DWALPager(%s) remapCleanup stopped (stop=%d)\n", self->filename.c_str(), self->remapCleanupStop);
signal.send(Void());
wait(tasks.getResult());
return Void();
}
// Flush all queues so they have no operations pending.
ACTOR static Future<Void> flushQueues(DWALPager* self) {
ASSERT(self->remapCleanupFuture.isReady());
// Flush remap queue separately, it's not involved in free page management
wait(self->remapQueue.flush());
// Flush the free list and delayed free list queues together as they are used by freePage() and newPageID()
// Since each queue's preFlush can create work for the other, we must see preflush return false for both
// twice in row.
state int clear = 0;
loop {
state bool freeBusy = wait(self->freeList.preFlush());
state bool delayedFreeBusy = wait(self->delayedFreeList.preFlush());
debug_printf("DWALPager(%s) flushQueues freeBusy=%d delayedFreeBusy=%d\n",
self->filename.c_str(),
freeBusy,
delayedFreeBusy);
// Once preFlush() returns false for both queues then there are no more operations pending
// on either queue. If preFlush() returns true for either queue in one loop execution then
// it could have generated new work for itself or the other queue.
if (!freeBusy && !delayedFreeBusy) {
if (++clear == 2) {
break;
}
} else {
clear = 0;
}
}
self->freeList.finishFlush();
self->delayedFreeList.finishFlush();
return Void();
}
ACTOR static Future<Void> commit_impl(DWALPager* self) {
debug_printf("DWALPager(%s) commit begin\n", self->filename.c_str());
// Write old committed header to Page 1
self->writeHeaderPage(1, self->lastCommittedHeaderPage);
// Trigger the remap eraser to stop and then wait for it.
self->remapCleanupStop = true;
wait(self->remapCleanupFuture);
wait(flushQueues(self));
self->pHeader->remapQueue = self->remapQueue.getState();
self->pHeader->freeList = self->freeList.getState();
self->pHeader->delayedFreeList = self->delayedFreeList.getState();
// Wait for all outstanding writes to complete
debug_printf("DWALPager(%s) waiting for outstanding writes\n", self->filename.c_str());
wait(self->operations.signalAndCollapse());
debug_printf("DWALPager(%s) Syncing\n", self->filename.c_str());
// Sync everything except the header
if (g_network->getCurrentTask() > TaskPriority::DiskWrite) {
wait(delay(0, TaskPriority::DiskWrite));
}
if (!self->memoryOnly) {
wait(self->pageFile->sync());
debug_printf("DWALPager(%s) commit version %" PRId64 " sync 1\n",
self->filename.c_str(),
self->pHeader->committedVersion);
}
// Update header on disk and sync again.
wait(self->writeHeaderPage(0, self->headerPage));
if (g_network->getCurrentTask() > TaskPriority::DiskWrite) {
wait(delay(0, TaskPriority::DiskWrite));
}
if (!self->memoryOnly) {
wait(self->pageFile->sync());
debug_printf("DWALPager(%s) commit version %" PRId64 " sync 2\n",
self->filename.c_str(),
self->pHeader->committedVersion);
}
// Update the last committed header for use in the next commit.
self->updateCommittedHeader();
self->addLatestSnapshot();
// Try to expire snapshots up to the oldest version, in case some were being kept around due to being in use,
// because maybe some are no longer in use.
self->expireSnapshots(self->pHeader->oldestVersion);
// Start unmapping pages for expired versions
self->remapCleanupFuture = remapCleanup(self);
return Void();
}
Future<Void> commit() override {
// Can't have more than one commit outstanding.
ASSERT(commitFuture.isReady());
commitFuture = forwardError(commit_impl(this), errorPromise);
return commitFuture;
}
Key getMetaKey() const override { return pHeader->getMetaKey(); }
void setCommitVersion(Version v) override { pHeader->committedVersion = v; }
void setMetaKey(KeyRef metaKey) override { pHeader->setMetaKey(metaKey); }
ACTOR void shutdown(DWALPager* self, bool dispose) {
debug_printf("DWALPager(%s) shutdown cancel recovery\n", self->filename.c_str());
self->recoverFuture.cancel();
debug_printf("DWALPager(%s) shutdown cancel commit\n", self->filename.c_str());
self->commitFuture.cancel();
debug_printf("DWALPager(%s) shutdown cancel remap\n", self->filename.c_str());
self->remapCleanupFuture.cancel();
if (self->errorPromise.canBeSet()) {
debug_printf("DWALPager(%s) shutdown sending error\n", self->filename.c_str());
self->errorPromise.sendError(actor_cancelled()); // Ideally this should be shutdown_in_progress
}
// Must wait for pending operations to complete, canceling them can cause a crash because the underlying
// operations may be uncancellable and depend on memory from calling scope's page reference
debug_printf("DWALPager(%s) shutdown wait for operations\n", self->filename.c_str());
wait(self->operations.signal());
debug_printf("DWALPager(%s) shutdown destroy page cache\n", self->filename.c_str());
wait(self->pageCache.clear());
// Unreference the file and clear
self->pageFile.clear();
if (dispose) {
if (!self->memoryOnly) {
debug_printf("DWALPager(%s) shutdown deleting file\n", self->filename.c_str());
wait(IAsyncFileSystem::filesystem()->incrementalDeleteFile(self->filename, true));
}
}
self->closedPromise.send(Void());
delete self;
}
void dispose() override { shutdown(this, true); }
void close() override { shutdown(this, false); }
Future<Void> getError() override { return errorPromise.getFuture(); }
Future<Void> onClosed() override { return closedPromise.getFuture(); }
StorageBytes getStorageBytes() const override {
ASSERT(recoverFuture.isReady());
int64_t free;
int64_t total;
if (memoryOnly) {
total = pageCacheBytes;
free = pageCacheBytes - ((int64_t)pageCache.count() * physicalPageSize);
} else {
g_network->getDiskBytes(parentDirectory(filename), free, total);
}
int64_t pagerSize = pHeader->pageCount * physicalPageSize;
// It is not exactly known how many pages on the delayed free list are usable as of right now. It could be
// known, if each commit delayed entries that were freeable were shuffled from the delayed free queue to the
// free queue, but this doesn't seem necessary.
int64_t reusable = (freeList.numEntries + delayedFreeList.numEntries) * physicalPageSize;
int64_t temp = remapQueue.numEntries * physicalPageSize;
return StorageBytes(free, total, pagerSize - reusable, free + reusable, temp);
}
ACTOR static Future<Void> getUserPageCount_cleanup(DWALPager* self) {
// Wait for the remap eraser to finish all of its work (not triggering stop)
wait(self->remapCleanupFuture);
// Flush queues so there are no pending freelist operations
wait(flushQueues(self));
return Void();
}
// Get the number of pages in use by the pager's user
Future<int64_t> getUserPageCount() override {
return map(getUserPageCount_cleanup(this), [=](Void) {
int64_t userPages = pHeader->pageCount - 2 - freeList.numPages - freeList.numEntries -
delayedFreeList.numPages - delayedFreeList.numEntries - remapQueue.numPages;
debug_printf("DWALPager(%s) userPages=%" PRId64 " totalPageCount=%" PRId64 " freeQueuePages=%" PRId64
" freeQueueCount=%" PRId64 " delayedFreeQueuePages=%" PRId64 " delayedFreeQueueCount=%" PRId64
" remapQueuePages=%" PRId64 " remapQueueCount=%" PRId64 "\n",
filename.c_str(),
userPages,
pHeader->pageCount,
freeList.numPages,
freeList.numEntries,
delayedFreeList.numPages,
delayedFreeList.numEntries,
remapQueue.numPages,
remapQueue.numEntries);
return userPages;
});
}
Future<Void> init() override { return recoverFuture; }
Version getLatestVersion() const override { return pLastCommittedHeader->committedVersion; }
private:
~DWALPager() {}
// Try to expire snapshots up to but not including v, but do not expire any snapshots that are in use.
void expireSnapshots(Version v);
#pragma pack(push, 1)
// Header is the format of page 0 of the database
struct Header {
static constexpr int FORMAT_VERSION = 2;
uint16_t formatVersion;
uint32_t pageSize;
int64_t pageCount;
FIFOQueue<LogicalPageID>::QueueState freeList;
FIFOQueue<DelayedFreePage>::QueueState delayedFreeList;
FIFOQueue<RemappedPage>::QueueState remapQueue;
Version committedVersion;
Version oldestVersion;
int32_t metaKeySize;
KeyRef getMetaKey() const { return KeyRef((const uint8_t*)(this + 1), metaKeySize); }
void setMetaKey(StringRef key) {
ASSERT(key.size() < (smallestPhysicalBlock - sizeof(Header)));
metaKeySize = key.size();
if (key.size() > 0) {
memcpy(this + 1, key.begin(), key.size());
}
}
int size() const { return sizeof(Header) + metaKeySize; }
private:
Header();
};
#pragma pack(pop)
struct PageCacheEntry {
Future<Reference<ArenaPage>> readFuture;
Future<Void> writeFuture;
bool initialized() const { return readFuture.isValid(); }
bool reading() const { return !readFuture.isReady(); }
bool writing() const { return !writeFuture.isReady(); }
bool evictable() const {
// Don't evict if a page is still being read or written
return !reading() && !writing();
}
Future<Void> onEvictable() const { return ready(readFuture) && writeFuture; }
};
// Physical page sizes will always be a multiple of 4k because AsyncFileNonDurable requires
// this in simulation, and it also makes sense for current SSDs.
// Allowing a smaller 'logical' page size is very useful for testing.
static constexpr int smallestPhysicalBlock = 4096;
int physicalPageSize;
int logicalPageSize; // In simulation testing it can be useful to use a small logical page size
int64_t pageCacheBytes;
// The header will be written to / read from disk as a smallestPhysicalBlock sized chunk.
Reference<ArenaPage> headerPage;
Header* pHeader;
int desiredPageSize;
Reference<ArenaPage> lastCommittedHeaderPage;
Header* pLastCommittedHeader;
std::string filename;
bool memoryOnly;
typedef ObjectCache<LogicalPageID, PageCacheEntry> PageCacheT;
PageCacheT pageCache;
Promise<Void> closedPromise;
Promise<Void> errorPromise;
Future<Void> commitFuture;
SignalableActorCollection operations;
Future<Void> recoverFuture;
Future<Void> remapCleanupFuture;
bool remapCleanupStop;
Reference<IAsyncFile> pageFile;
LogicalPageQueueT freeList;
// The delayed free list will be approximately in Version order.
// TODO: Make this an ordered container some day.
DelayedFreePageQueueT delayedFreeList;
RemapQueueT remapQueue;
Version remapCleanupWindow;
std::unordered_set<PhysicalPageID> remapDestinationsSimOnly;
struct SnapshotEntry {
Version version;
Promise<Void> expired;
Reference<DWALPagerSnapshot> snapshot;
};
struct SnapshotEntryLessThanVersion {
bool operator()(Version v, const SnapshotEntry& snapshot) { return v < snapshot.version; }
bool operator()(const SnapshotEntry& snapshot, Version v) { return snapshot.version < v; }
};
// TODO: Better data structure
PageToVersionedMapT remappedPages;
std::deque<SnapshotEntry> snapshots;
};
// Prevents pager from reusing freed pages from version until the snapshot is destroyed
class DWALPagerSnapshot : public IPagerSnapshot, public ReferenceCounted<DWALPagerSnapshot> {
public:
DWALPagerSnapshot(DWALPager* pager, Key meta, Version version, Future<Void> expiredFuture)
: pager(pager), metaKey(meta), version(version), expired(expiredFuture) {}
~DWALPagerSnapshot() override {}
Future<Reference<const ArenaPage>> getPhysicalPage(LogicalPageID pageID,
bool cacheable,
bool noHit,
bool* fromCache) override {
if (expired.isError()) {
throw expired.getError();
}
return map(pager->readPageAtVersion(pageID, version, cacheable, noHit, fromCache),
[=](Reference<ArenaPage> p) { return Reference<const ArenaPage>(std::move(p)); });
}
bool tryEvictPage(LogicalPageID id) override { return pager->tryEvictPage(id, version); }
Key getMetaKey() const override { return metaKey; }
Version getVersion() const override { return version; }
void addref() override { ReferenceCounted<DWALPagerSnapshot>::addref(); }
void delref() override { ReferenceCounted<DWALPagerSnapshot>::delref(); }
DWALPager* pager;
Future<Void> expired;
Version version;
Key metaKey;
};
void DWALPager::expireSnapshots(Version v) {
debug_printf("DWALPager(%s) expiring snapshots through %" PRId64 " snapshot count %d\n",
filename.c_str(),
v,
(int)snapshots.size());
while (snapshots.size() > 1 && snapshots.front().version < v && snapshots.front().snapshot->isSoleOwner()) {
debug_printf("DWALPager(%s) expiring snapshot for %" PRId64 " soleOwner=%d\n",
filename.c_str(),
snapshots.front().version,
snapshots.front().snapshot->isSoleOwner());
// The snapshot contract could be made such that the expired promise isn't need anymore. In practice it
// probably is already not needed but it will gracefully handle the case where a user begins a page read
// with a snapshot reference, keeps the page read future, and drops the snapshot reference.
snapshots.front().expired.sendError(transaction_too_old());
snapshots.pop_front();
}
}
Reference<IPagerSnapshot> DWALPager::getReadSnapshot(Version v) {
ASSERT(!snapshots.empty());
auto i = std::upper_bound(snapshots.begin(), snapshots.end(), v, SnapshotEntryLessThanVersion());
if (i == snapshots.begin()) {
throw version_invalid();
}
--i;
return i->snapshot;
}
void DWALPager::addLatestSnapshot() {
Promise<Void> expired;
snapshots.push_back(
{ pLastCommittedHeader->committedVersion,
expired,
makeReference<DWALPagerSnapshot>(
this, pLastCommittedHeader->getMetaKey(), pLastCommittedHeader->committedVersion, expired.getFuture()) });
}
// TODO: Move this to a flow header once it is mature.
struct SplitStringRef {
StringRef a;
StringRef b;
SplitStringRef(StringRef a = StringRef(), StringRef b = StringRef()) : a(a), b(b) {}
SplitStringRef(Arena& arena, const SplitStringRef& toCopy) : a(toStringRef(arena)), b() {}
SplitStringRef prefix(int len) const {
if (len <= a.size()) {
return SplitStringRef(a.substr(0, len));
}
len -= a.size();
return SplitStringRef(a, b.substr(0, len));
}
StringRef toStringRef(Arena& arena) const {
StringRef c = makeString(size(), arena);
memcpy(mutateString(c), a.begin(), a.size());
memcpy(mutateString(c) + a.size(), b.begin(), b.size());
return c;
}
Standalone<StringRef> toStringRef() const {
Arena a;
return Standalone<StringRef>(toStringRef(a), a);
}
int size() const { return a.size() + b.size(); }
int expectedSize() const { return size(); }
std::string toString() const { return format("%s%s", a.toString().c_str(), b.toString().c_str()); }
std::string toHexString() const { return format("%s%s", a.toHexString().c_str(), b.toHexString().c_str()); }
struct const_iterator {
const uint8_t* ptr;
const uint8_t* end;
const uint8_t* next;
inline bool operator==(const const_iterator& rhs) const { return ptr == rhs.ptr; }
inline bool operator!=(const const_iterator& rhs) const { return !(*this == rhs); }
inline const_iterator& operator++() {
++ptr;
if (ptr == end) {
ptr = next;
}
return *this;
}
inline const_iterator& operator+(int n) {
ptr += n;
if (ptr >= end) {
ptr = next + (ptr - end);
}
return *this;
}
inline uint8_t operator*() const { return *ptr; }
};
inline const_iterator begin() const { return { a.begin(), a.end(), b.begin() }; }
inline const_iterator end() const { return { b.end() }; }
template <typename StringT>
int compare(const StringT& rhs) const {
auto j = begin();
auto k = rhs.begin();
auto jEnd = end();
auto kEnd = rhs.end();
while (j != jEnd && k != kEnd) {
int cmp = *j - *k;
if (cmp != 0) {
return cmp;
}
}
// If we've reached the end of *this, then values are equal if rhs is also exhausted, otherwise *this is less
// than rhs
if (j == jEnd) {
return k == kEnd ? 0 : -1;
}
return 1;
}
};
// A BTree "page id" is actually a list of LogicalPageID's whose contents should be concatenated together.
// NOTE: Uses host byte order
typedef VectorRef<LogicalPageID> BTreePageIDRef;
constexpr LogicalPageID maxPageID = (LogicalPageID)-1;
std::string toString(BTreePageIDRef id) {
return std::string("BTreePageID") + toString(id.begin(), id.end());
}
#define STR(x) LiteralStringRef(x)
struct RedwoodRecordRef {
typedef uint8_t byte;
RedwoodRecordRef(KeyRef key = KeyRef(), Version ver = 0, Optional<ValueRef> value = {})
: key(key), version(ver), value(value) {}
RedwoodRecordRef(Arena& arena, const RedwoodRecordRef& toCopy) : key(arena, toCopy.key), version(toCopy.version) {
if (toCopy.value.present()) {
value = ValueRef(arena, toCopy.value.get());
}
}
KeyValueRef toKeyValueRef() const { return KeyValueRef(key, value.get()); }
// RedwoodRecordRefs are used for both internal and leaf pages of the BTree.
// Boundary records in internal pages are made from leaf records.
// These functions make creating and working with internal page records more convenient.
inline BTreePageIDRef getChildPage() const {
ASSERT(value.present());
return BTreePageIDRef((LogicalPageID*)value.get().begin(), value.get().size() / sizeof(LogicalPageID));
}
inline void setChildPage(BTreePageIDRef id) {
value = ValueRef((const uint8_t*)id.begin(), id.size() * sizeof(LogicalPageID));
}
inline void setChildPage(Arena& arena, BTreePageIDRef id) {
value = ValueRef(arena, (const uint8_t*)id.begin(), id.size() * sizeof(LogicalPageID));
}
inline RedwoodRecordRef withPageID(BTreePageIDRef id) const {
return RedwoodRecordRef(key, version, ValueRef((const uint8_t*)id.begin(), id.size() * sizeof(LogicalPageID)));
}
inline RedwoodRecordRef withoutValue() const { return RedwoodRecordRef(key, version); }
inline RedwoodRecordRef withMaxPageID() const {
return RedwoodRecordRef(key, version, StringRef((uint8_t*)&maxPageID, sizeof(maxPageID)));
}
// Truncate (key, version, part) tuple to len bytes.
void truncate(int len) {
ASSERT(len <= key.size());
key = key.substr(0, len);
version = 0;
}
// Find the common key prefix between two records, assuming that the first skipLen bytes are the same
inline int getCommonPrefixLen(const RedwoodRecordRef& other, int skipLen = 0) const {
return skipLen + commonPrefixLength(key, other.key, skipLen);
}
// Compares and orders by key, version, chunk.total, chunk.start, value
// This is the same order that delta compression uses for prefix borrowing
int compare(const RedwoodRecordRef& rhs, int skip = 0) const {
int keySkip = std::min(skip, key.size());
int cmp = key.compareSuffix(rhs.key, keySkip);
if (cmp == 0) {
cmp = version - rhs.version;
if (cmp == 0) {
cmp = value.compare(rhs.value);
}
}
return cmp;
}
bool sameUserKey(const StringRef& k, int skipLen) const {
// Keys are the same if the sizes are the same and either the skipLen is longer or the non-skipped suffixes are
// the same.
return (key.size() == k.size()) && (key.substr(skipLen) == k.substr(skipLen));
}
bool sameExceptValue(const RedwoodRecordRef& rhs, int skipLen = 0) const {
return sameUserKey(rhs.key, skipLen) && version == rhs.version;
}
// TODO: Use SplitStringRef (unless it ends up being slower)
KeyRef key;
Optional<ValueRef> value;
Version version;
int expectedSize() const { return key.expectedSize() + value.expectedSize(); }
int kvBytes() const { return expectedSize(); }
class Reader {
public:
Reader(const void* ptr) : rptr((const byte*)ptr) {}
const byte* rptr;
StringRef readString(int len) {
StringRef s(rptr, len);
rptr += len;
return s;
}
};
#pragma pack(push, 1)
struct Delta {
uint8_t flags;
// Four field sizing schemes ranging from 3 to 8 bytes, with 3 being the most common.
union {
struct {
uint8_t prefixLength;
uint8_t suffixLength;
uint8_t valueLength;
} LengthFormat0;
struct {
uint8_t prefixLength;
uint8_t suffixLength;
uint16_t valueLength;
} LengthFormat1;
struct {
uint8_t prefixLength;
uint8_t suffixLength;
uint32_t valueLength;
} LengthFormat2;
struct {
uint16_t prefixLength;
uint16_t suffixLength;
uint32_t valueLength;
} LengthFormat3;
};
struct int48_t {
static constexpr int64_t MASK = 0xFFFFFFFFFFFFLL;
int32_t high;
int16_t low;
};
static constexpr int LengthFormatSizes[] = { sizeof(LengthFormat0),
sizeof(LengthFormat1),
sizeof(LengthFormat2),
sizeof(LengthFormat3) };
static constexpr int VersionDeltaSizes[] = { 0, sizeof(int32_t), sizeof(int48_t), sizeof(int64_t) };
// Serialized Format
//
// Flags - 1 byte
// 1 bit - borrow source is prev ancestor (otherwise next ancestor)
// 1 bit - item is deleted
// 1 bit - has value (different from zero-length value, if 0 value len will be 0)
// 1 bits - has nonzero version
// 2 bits - version delta integer size code, maps to 0, 4, 6, 8
// 2 bits - length fields format
//
// Length fields using 3 to 8 bytes total depending on length fields format
//
// Byte strings
// Key suffix bytes
// Value bytes
// Version delta bytes
//
enum EFlags {
PREFIX_SOURCE_PREV = 0x80,
IS_DELETED = 0x40,
HAS_VALUE = 0x20,
HAS_VERSION = 0x10,
VERSION_DELTA_SIZE = 0xC,
LENGTHS_FORMAT = 0x03
};
static inline int determineLengthFormat(int prefixLength, int suffixLength, int valueLength) {
// Large prefix or suffix length, which should be rare, is format 3
if (prefixLength > 0xFF || suffixLength > 0xFF) {
return 3;
} else if (valueLength < 0x100) {
return 0;
} else if (valueLength < 0x10000) {
return 1;
} else {
return 2;
}
}
// Large prefix or suffix length, which should be rare, is format 3
byte* data() const {
switch (flags & LENGTHS_FORMAT) {
case 0:
return (byte*)(&LengthFormat0 + 1);
case 1:
return (byte*)(&LengthFormat1 + 1);
case 2:
return (byte*)(&LengthFormat2 + 1);
case 3:
default:
return (byte*)(&LengthFormat3 + 1);
}
}
int getKeyPrefixLength() const {
switch (flags & LENGTHS_FORMAT) {
case 0:
return LengthFormat0.prefixLength;
case 1:
return LengthFormat1.prefixLength;
case 2:
return LengthFormat2.prefixLength;
case 3:
default:
return LengthFormat3.prefixLength;
}
}
int getKeySuffixLength() const {
switch (flags & LENGTHS_FORMAT) {
case 0:
return LengthFormat0.suffixLength;
case 1:
return LengthFormat1.suffixLength;
case 2:
return LengthFormat2.suffixLength;
case 3:
default:
return LengthFormat3.suffixLength;
}
}
int getValueLength() const {
switch (flags & LENGTHS_FORMAT) {
case 0:
return LengthFormat0.valueLength;
case 1:
return LengthFormat1.valueLength;
case 2:
return LengthFormat2.valueLength;
case 3:
default:
return LengthFormat3.valueLength;
}
}
StringRef getKeySuffix() const { return StringRef(data(), getKeySuffixLength()); }
StringRef getValue() const { return StringRef(data() + getKeySuffixLength(), getValueLength()); }
bool hasVersion() const { return flags & HAS_VERSION; }
int getVersionDeltaSizeBytes() const {
int code = (flags & VERSION_DELTA_SIZE) >> 2;
return VersionDeltaSizes[code];
}
static int getVersionDeltaSizeBytes(Version d) {
if (d == 0) {
return 0;
} else if (d == (int32_t)d) {
return sizeof(int32_t);
} else if (d == (d & int48_t::MASK)) {
return sizeof(int48_t);
}
return sizeof(int64_t);
}
int getVersionDelta(const uint8_t* r) const {
int code = (flags & VERSION_DELTA_SIZE) >> 2;
switch (code) {
case 0:
return 0;
case 1:
return *(int32_t*)r;
case 2:
return (((int64_t)((int48_t*)r)->high) << 16) | (((int48_t*)r)->low & 0xFFFF);
case 3:
default:
return *(int64_t*)r;
}
}
// Version delta size should be 0 before calling
int setVersionDelta(Version d, uint8_t* w) {
flags |= HAS_VERSION;
if (d == 0) {
return 0;
} else if (d == (int32_t)d) {
flags |= 1 << 2;
*(uint32_t*)w = d;
return sizeof(uint32_t);
} else if (d == (d & int48_t::MASK)) {
flags |= 2 << 2;
((int48_t*)w)->high = d >> 16;
((int48_t*)w)->low = d;
return sizeof(int48_t);
} else {
flags |= 3 << 2;
*(int64_t*)w = d;
return sizeof(int64_t);
}
}
bool hasValue() const { return flags & HAS_VALUE; }
void setPrefixSource(bool val) {
if (val) {
flags |= PREFIX_SOURCE_PREV;
} else {
flags &= ~PREFIX_SOURCE_PREV;
}
}
bool getPrefixSource() const { return flags & PREFIX_SOURCE_PREV; }
void setDeleted(bool val) {
if (val) {
flags |= IS_DELETED;
} else {
flags &= ~IS_DELETED;
}
}
bool getDeleted() const { return flags & IS_DELETED; }
RedwoodRecordRef apply(const RedwoodRecordRef& base, Arena& arena) const {
int keyPrefixLen = getKeyPrefixLength();
int keySuffixLen = getKeySuffixLength();
int valueLen = hasValue() ? getValueLength() : 0;
StringRef k;
Reader r(data());
// If there is a key suffix, reconstitute the complete key into a contiguous string
if (keySuffixLen > 0) {
StringRef keySuffix = r.readString(keySuffixLen);
k = makeString(keyPrefixLen + keySuffixLen, arena);
memcpy(mutateString(k), base.key.begin(), keyPrefixLen);
memcpy(mutateString(k) + keyPrefixLen, keySuffix.begin(), keySuffixLen);
} else {
// Otherwise just reference the base key's memory
k = base.key.substr(0, keyPrefixLen);
}
Optional<ValueRef> value;
if (hasValue()) {
value = r.readString(valueLen);
}
Version v = 0;
if (hasVersion()) {
v = base.version + getVersionDelta(r.rptr);
}
return RedwoodRecordRef(k, v, value);
}
int size() const {
int size = 1 + getVersionDeltaSizeBytes();
switch (flags & LENGTHS_FORMAT) {
case 0:
return size + sizeof(LengthFormat0) + LengthFormat0.suffixLength + LengthFormat0.valueLength;
case 1:
return size + sizeof(LengthFormat1) + LengthFormat1.suffixLength + LengthFormat1.valueLength;
case 2:
return size + sizeof(LengthFormat2) + LengthFormat2.suffixLength + LengthFormat2.valueLength;
case 3:
default:
return size + sizeof(LengthFormat3) + LengthFormat3.suffixLength + LengthFormat3.valueLength;
}
}
std::string toString() const {
std::string flagString = " ";
if (flags & PREFIX_SOURCE_PREV) {
flagString += "PrefixSource|";
}
if (flags & IS_DELETED) {
flagString += "IsDeleted|";
}
if (hasValue()) {
flagString += "HasValue|";
}
if (hasVersion()) {
flagString += "HasVersion|";
}
int lengthFormat = flags & LENGTHS_FORMAT;
Reader r(data());
int prefixLen = getKeyPrefixLength();
int keySuffixLen = getKeySuffixLength();
int valueLen = getValueLength();
return format("lengthFormat: %d totalDeltaSize: %d flags: %s prefixLen: %d keySuffixLen: %d "
"versionDeltaSizeBytes: %d valueLen %d raw: %s",
lengthFormat,
size(),
flagString.c_str(),
prefixLen,
keySuffixLen,
getVersionDeltaSizeBytes(),
valueLen,
StringRef((const uint8_t*)this, size()).toHexString().c_str());
}
};
// Using this class as an alternative for Delta enables reading a DeltaTree<RecordRef> while only decoding
// its values, so the Reader does not require the original prev/next ancestors.
struct DeltaValueOnly : Delta {
RedwoodRecordRef apply(const RedwoodRecordRef& base, Arena& arena) const {
Optional<ValueRef> value;
if (hasValue()) {
value = getValue();
}
return RedwoodRecordRef(StringRef(), 0, value);
}
};
#pragma pack(pop)
bool operator==(const RedwoodRecordRef& rhs) const { return compare(rhs) == 0; }
bool operator!=(const RedwoodRecordRef& rhs) const { return compare(rhs) != 0; }
bool operator<(const RedwoodRecordRef& rhs) const { return compare(rhs) < 0; }
bool operator>(const RedwoodRecordRef& rhs) const { return compare(rhs) > 0; }
bool operator<=(const RedwoodRecordRef& rhs) const { return compare(rhs) <= 0; }
bool operator>=(const RedwoodRecordRef& rhs) const { return compare(rhs) >= 0; }
// Worst case overhead means to assume that either the prefix length or the suffix length
// could contain the full key size
int deltaSize(const RedwoodRecordRef& base, int skipLen, bool worstCaseOverhead) const {
int prefixLen = getCommonPrefixLen(base, skipLen);
int keySuffixLen = key.size() - prefixLen;
int valueLen = value.present() ? value.get().size() : 0;
int formatType;
int versionBytes;
if (worstCaseOverhead) {
formatType = Delta::determineLengthFormat(key.size(), key.size(), valueLen);
versionBytes = version == 0 ? 0 : Delta::getVersionDeltaSizeBytes(version << 1);
} else {
formatType = Delta::determineLengthFormat(prefixLen, keySuffixLen, valueLen);
versionBytes = version == 0 ? 0 : Delta::getVersionDeltaSizeBytes(version - base.version);
}
return 1 + Delta::LengthFormatSizes[formatType] + keySuffixLen + valueLen + versionBytes;
}
// commonPrefix between *this and base can be passed if known
int writeDelta(Delta& d, const RedwoodRecordRef& base, int keyPrefixLen = -1) const {
d.flags = value.present() ? Delta::HAS_VALUE : 0;
if (keyPrefixLen < 0) {
keyPrefixLen = getCommonPrefixLen(base, 0);
}
StringRef keySuffix = key.substr(keyPrefixLen);
int valueLen = value.present() ? value.get().size() : 0;
int formatType = Delta::determineLengthFormat(keyPrefixLen, keySuffix.size(), valueLen);
d.flags |= formatType;
switch (formatType) {
case 0:
d.LengthFormat0.prefixLength = keyPrefixLen;
d.LengthFormat0.suffixLength = keySuffix.size();
d.LengthFormat0.valueLength = valueLen;
break;
case 1:
d.LengthFormat1.prefixLength = keyPrefixLen;
d.LengthFormat1.suffixLength = keySuffix.size();
d.LengthFormat1.valueLength = valueLen;
break;
case 2:
d.LengthFormat2.prefixLength = keyPrefixLen;
d.LengthFormat2.suffixLength = keySuffix.size();
d.LengthFormat2.valueLength = valueLen;
break;
case 3:
default:
d.LengthFormat3.prefixLength = keyPrefixLen;
d.LengthFormat3.suffixLength = keySuffix.size();
d.LengthFormat3.valueLength = valueLen;
break;
}
uint8_t* wptr = d.data();
// Write key suffix string
wptr = keySuffix.copyTo(wptr);
// Write value bytes
if (value.present()) {
wptr = value.get().copyTo(wptr);
}
if (version != 0) {
wptr += d.setVersionDelta(version - base.version, wptr);
}
return wptr - (uint8_t*)&d;
}
static std::string kvformat(StringRef s, int hexLimit = -1) {
bool hex = false;
for (auto c : s) {
if (!isprint(c)) {
hex = true;
break;
}
}
return hex ? s.toHexString(hexLimit) : s.toString();
}
std::string toString(bool leaf = true) const {
std::string r;
r += format("'%s'@%" PRId64 " => ", key.printable().c_str(), version);
if (value.present()) {
if (leaf) {
r += format("'%s'", kvformat(value.get()).c_str());
} else {
r += format("[%s]", ::toString(getChildPage()).c_str());
}
} else {
r += "(absent)";
}
return r;
}
};
struct BTreePage {
typedef DeltaTree<RedwoodRecordRef> BinaryTree;
typedef DeltaTree<RedwoodRecordRef, RedwoodRecordRef::DeltaValueOnly> ValueTree;
#pragma pack(push, 1)
struct {
uint8_t height;
uint32_t kvBytes;
};
#pragma pack(pop)
int size() const {
auto& t = tree();
return (uint8_t*)&t - (uint8_t*)this + t.size();
}
bool isLeaf() const { return height == 1; }
BinaryTree& tree() { return *(BinaryTree*)(this + 1); }
const BinaryTree& tree() const { return *(const BinaryTree*)(this + 1); }
const ValueTree& valueTree() const { return *(const ValueTree*)(this + 1); }
// TODO: boundaries are for decoding, but upper
std::string toString(bool write,
BTreePageIDRef id,
Version ver,
const RedwoodRecordRef* lowerBound,
const RedwoodRecordRef* upperBound) const {
std::string r;
r += format("BTreePage op=%s %s @%" PRId64
" ptr=%p height=%d count=%d kvBytes=%d\n lowerBound: %s\n upperBound: %s\n",
write ? "write" : "read",
::toString(id).c_str(),
ver,
this,
height,
(int)tree().numItems,
(int)kvBytes,
lowerBound->toString(false).c_str(),
upperBound->toString(false).c_str());
try {
if (tree().numItems > 0) {
// This doesn't use the cached reader for the page because it is only for debugging purposes,
// a cached reader may not exist
BinaryTree::Mirror reader(&tree(), lowerBound, upperBound);
BinaryTree::Cursor c = reader.getCursor();
c.moveFirst();
ASSERT(c.valid());
bool anyOutOfRange = false;
do {
r += " ";
r += c.get().toString(height == 1);
bool tooLow = c.get().withoutValue() < lowerBound->withoutValue();
bool tooHigh = c.get().withoutValue() >= upperBound->withoutValue();
if (tooLow || tooHigh) {
anyOutOfRange = true;
if (tooLow) {
r += " (below decode lower bound)";
}
if (tooHigh) {
r += " (at or above decode upper bound)";
}
}
r += "\n";
} while (c.moveNext());
// Out of range entries are actually okay now and the result of subtree deletion followed by
// incremental insertions of records in the deleted range being added to an adjacent subtree
// which is logically expanded encompass the deleted range but still is using the original
// subtree boundaries as DeltaTree boundaries.
// ASSERT(!anyOutOfRange);
}
} catch (Error& e) {
debug_printf("BTreePage::toString ERROR: %s\n", e.what());
debug_printf("BTreePage::toString partial result: %s\n", r.c_str());
throw;
}
// All appends to r end in a linefeed, remove the final one.
r.resize(r.size() - 1);
return r;
}
};
static void makeEmptyRoot(Reference<ArenaPage> page) {
BTreePage* btpage = (BTreePage*)page->begin();
btpage->height = 1;
btpage->kvBytes = 0;
btpage->tree().build(page->size(), nullptr, nullptr, nullptr, nullptr);
}
BTreePage::BinaryTree::Cursor getCursor(const Reference<const ArenaPage>& page) {
return ((BTreePage::BinaryTree::Mirror*)page->userData)->getCursor();
}
struct BoundaryRefAndPage {
Standalone<RedwoodRecordRef> lowerBound;
Reference<ArenaPage> firstPage;
std::vector<Reference<ArenaPage>> extPages;
std::string toString() const {
return format("[%s, %d pages]", lowerBound.toString().c_str(), extPages.size() + (firstPage ? 1 : 0));
}
};
#define NOT_IMPLEMENTED UNSTOPPABLE_ASSERT(false)
#pragma pack(push, 1)
template <typename T, typename SizeT = int8_t>
struct InPlaceArray {
SizeT count;
const T* begin() const { return (T*)(this + 1); }
T* begin() { return (T*)(this + 1); }
const T* end() const { return begin() + count; }
T* end() { return begin() + count; }
VectorRef<T> get() { return VectorRef<T>(begin(), count); }
void set(VectorRef<T> v, int availableSpace) {
ASSERT(sizeof(T) * v.size() <= availableSpace);
count = v.size();
memcpy(begin(), v.begin(), sizeof(T) * v.size());
}
int extraSize() const { return count * sizeof(T); }
};
#pragma pack(pop)
class VersionedBTree final : public IVersionedStore {
public:
// The first possible internal record possible in the tree
static RedwoodRecordRef dbBegin;
// A record which is greater than the last possible record in the tree
static RedwoodRecordRef dbEnd;
struct LazyClearQueueEntry {
Version version;
Standalone<BTreePageIDRef> pageID;
bool operator<(const LazyClearQueueEntry& rhs) const { return version < rhs.version; }
int readFromBytes(const uint8_t* src) {
version = *(Version*)src;
src += sizeof(Version);
int count = *src++;
pageID = BTreePageIDRef((LogicalPageID*)src, count);
return bytesNeeded();
}
int bytesNeeded() const { return sizeof(Version) + 1 + (pageID.size() * sizeof(LogicalPageID)); }
int writeToBytes(uint8_t* dst) const {
*(Version*)dst = version;
dst += sizeof(Version);
*dst++ = pageID.size();
memcpy(dst, pageID.begin(), pageID.size() * sizeof(LogicalPageID));
return bytesNeeded();
}
std::string toString() const { return format("{%s @%" PRId64 "}", ::toString(pageID).c_str(), version); }
};
typedef FIFOQueue<LazyClearQueueEntry> LazyClearQueueT;
struct ParentInfo {
ParentInfo() {
count = 0;
bits = 0;
}
void clear() {
count = 0;
bits = 0;
}
static uint32_t mask(LogicalPageID id) { return 1 << (id & 31); }
void pageUpdated(LogicalPageID child) {
auto m = mask(child);
if ((bits & m) == 0) {
bits |= m;
++count;
}
}
bool maybeUpdated(LogicalPageID child) { return (mask(child) & bits) != 0; }
uint32_t bits;
int count;
};
typedef std::unordered_map<LogicalPageID, ParentInfo> ParentInfoMapT;
#pragma pack(push, 1)
struct MetaKey {
static constexpr int FORMAT_VERSION = 8;
// This serves as the format version for the entire tree, individual pages will not be versioned
uint16_t formatVersion;
uint8_t height;
LazyClearQueueT::QueueState lazyDeleteQueue;
InPlaceArray<LogicalPageID> root;
KeyRef asKeyRef() const { return KeyRef((uint8_t*)this, sizeof(MetaKey) + root.extraSize()); }
void fromKeyRef(KeyRef k) {
memcpy(this, k.begin(), k.size());
ASSERT(formatVersion == FORMAT_VERSION);
}
std::string toString() {
return format("{height=%d formatVersion=%d root=%s lazyDeleteQueue=%s}",
(int)height,
(int)formatVersion,
::toString(root.get()).c_str(),
lazyDeleteQueue.toString().c_str());
}
};
#pragma pack(pop)
// All async opts on the btree are based on pager reads, writes, and commits, so
// we can mostly forward these next few functions to the pager
Future<Void> getError() override { return m_pager->getError(); }
Future<Void> onClosed() override { return m_pager->onClosed(); }
void close_impl(bool dispose) {
auto* pager = m_pager;
delete this;
if (dispose)
pager->dispose();
else
pager->close();
}
void dispose() override { return close_impl(true); }
void close() override { return close_impl(false); }
KeyValueStoreType getType() const override { NOT_IMPLEMENTED; }
bool supportsMutation(int op) const override { NOT_IMPLEMENTED; }
StorageBytes getStorageBytes() const override { return m_pager->getStorageBytes(); }
// Writes are provided in an ordered stream.
// A write is considered part of (a change leading to) the version determined by the previous call to
// setWriteVersion() A write shall not become durable until the following call to commit() begins, and shall be
// durable once the following call to commit() returns
void set(KeyValueRef keyValue) override {
++g_redwoodMetrics.opSet;
g_redwoodMetrics.opSetKeyBytes += keyValue.key.size();
g_redwoodMetrics.opSetValueBytes += keyValue.value.size();
m_pBuffer->insert(keyValue.key).mutation().setBoundaryValue(m_pBuffer->copyToArena(keyValue.value));
}
void clear(KeyRangeRef clearedRange) override {
// Optimization for single key clears to create just one mutation boundary instead of two
if (clearedRange.begin.size() == clearedRange.end.size() - 1 &&
clearedRange.end[clearedRange.end.size() - 1] == 0 && clearedRange.end.startsWith(clearedRange.begin)) {
++g_redwoodMetrics.opClear;
++g_redwoodMetrics.opClearKey;
m_pBuffer->insert(clearedRange.begin).mutation().clearBoundary();
return;
}
++g_redwoodMetrics.opClear;
MutationBuffer::iterator iBegin = m_pBuffer->insert(clearedRange.begin);
MutationBuffer::iterator iEnd = m_pBuffer->insert(clearedRange.end);
iBegin.mutation().clearAll();
++iBegin;
m_pBuffer->erase(iBegin, iEnd);
}
void mutate(int op, StringRef param1, StringRef param2) override { NOT_IMPLEMENTED; }
void setOldestVersion(Version v) override { m_newOldestVersion = v; }
Version getOldestVersion() const override { return m_pager->getOldestVersion(); }
Version getLatestVersion() const override {
if (m_writeVersion != invalidVersion)
return m_writeVersion;
return m_pager->getLatestVersion();
}
Version getWriteVersion() const { return m_writeVersion; }
Version getLastCommittedVersion() const { return m_lastCommittedVersion; }
VersionedBTree(IPager2* pager, std::string name)
: m_pager(pager), m_writeVersion(invalidVersion), m_lastCommittedVersion(invalidVersion), m_pBuffer(nullptr),
m_commitReadLock(new FlowLock(SERVER_KNOBS->REDWOOD_COMMIT_CONCURRENT_READS)), m_name(name) {
m_lazyClearActor = 0;
m_init = init_impl(this);
m_latestCommit = m_init;
}
ACTOR static Future<int> incrementalLazyClear(VersionedBTree* self) {
ASSERT(self->m_lazyClearActor.isReady());
self->m_lazyClearStop = false;
// TODO: Is it contractually okay to always to read at the latest version?
state Reference<IPagerSnapshot> snapshot = self->m_pager->getReadSnapshot(self->m_pager->getLatestVersion());
state int freedPages = 0;
loop {
state int toPop = SERVER_KNOBS->REDWOOD_LAZY_CLEAR_BATCH_SIZE_PAGES;
state std::vector<std::pair<LazyClearQueueEntry, Future<Reference<const ArenaPage>>>> entries;
entries.reserve(toPop);
// Take up to batchSize pages from front of queue
while (toPop > 0) {
Optional<LazyClearQueueEntry> q = wait(self->m_lazyClearQueue.pop());
debug_printf("LazyClear: popped %s\n", toString(q).c_str());
if (!q.present()) {
break;
}
// Start reading the page, without caching
entries.push_back(
std::make_pair(q.get(), self->readPage(snapshot, q.get().pageID, nullptr, nullptr, true, false)));
--toPop;
}
state int i;
for (i = 0; i < entries.size(); ++i) {
Reference<const ArenaPage> p = wait(entries[i].second);
const LazyClearQueueEntry& entry = entries[i].first;
const BTreePage& btPage = *(BTreePage*)p->begin();
auto& metrics = g_redwoodMetrics.level(btPage.height);
debug_printf("LazyClear: processing %s\n", toString(entry).c_str());
// Level 1 (leaf) nodes should never be in the lazy delete queue
ASSERT(btPage.height > 1);
// Iterate over page entries, skipping key decoding using BTreePage::ValueTree which uses
// RedwoodRecordRef::DeltaValueOnly as the delta type type to skip key decoding
BTreePage::ValueTree::Mirror reader(&btPage.valueTree(), &dbBegin, &dbEnd);
auto c = reader.getCursor();
ASSERT(c.moveFirst());
Version v = entry.version;
while (1) {
if (c.get().value.present()) {
BTreePageIDRef btChildPageID = c.get().getChildPage();
// If this page is height 2, then the children are leaves so free them directly
if (btPage.height == 2) {
debug_printf("LazyClear: freeing child %s\n", toString(btChildPageID).c_str());
self->freeBTreePage(btChildPageID, v);
freedPages += btChildPageID.size();
metrics.lazyClearFree += 1;
metrics.lazyClearFreeExt += (btChildPageID.size() - 1);
} else {
// Otherwise, queue them for lazy delete.
debug_printf("LazyClear: queuing child %s\n", toString(btChildPageID).c_str());
self->m_lazyClearQueue.pushFront(LazyClearQueueEntry{ v, btChildPageID });
metrics.lazyClearRequeue += 1;
metrics.lazyClearRequeueExt += (btChildPageID.size() - 1);
}
}
if (!c.moveNext()) {
break;
}
}
// Free the page, now that its children have either been freed or queued
debug_printf("LazyClear: freeing queue entry %s\n", toString(entry.pageID).c_str());
self->freeBTreePage(entry.pageID, v);
freedPages += entry.pageID.size();
metrics.lazyClearFree += 1;
metrics.lazyClearFreeExt += entry.pageID.size() - 1;
}
// Stop if
// - the poppable items in the queue have already been exhausted
// - stop flag is set and we've freed the minimum number of pages required
// - maximum number of pages to free met or exceeded
if (toPop > 0 || (freedPages >= SERVER_KNOBS->REDWOOD_LAZY_CLEAR_MIN_PAGES && self->m_lazyClearStop) ||
(freedPages >= SERVER_KNOBS->REDWOOD_LAZY_CLEAR_MAX_PAGES)) {
break;
}
}
debug_printf("LazyClear: freed %d pages, %s has %" PRId64 " entries\n",
freedPages,
self->m_lazyClearQueue.name.c_str(),
self->m_lazyClearQueue.numEntries);
return freedPages;
}
ACTOR static Future<Void> init_impl(VersionedBTree* self) {
wait(self->m_pager->init());
self->m_blockSize = self->m_pager->getUsablePageSize();
state Version latest = self->m_pager->getLatestVersion();
self->m_newOldestVersion = self->m_pager->getOldestVersion();
debug_printf("Recovered pager to version %" PRId64 ", oldest version is %" PRId64 "\n",
self->m_newOldestVersion);
state Key meta = self->m_pager->getMetaKey();
if (meta.size() == 0) {
self->m_header.formatVersion = MetaKey::FORMAT_VERSION;
LogicalPageID id = wait(self->m_pager->newPageID());
BTreePageIDRef newRoot((LogicalPageID*)&id, 1);
debug_printf("new root %s\n", toString(newRoot).c_str());
self->m_header.root.set(newRoot, sizeof(headerSpace) - sizeof(m_header));
self->m_header.height = 1;
++latest;
Reference<ArenaPage> page = self->m_pager->newPageBuffer();
makeEmptyRoot(page);
self->m_pager->updatePage(id, page);
self->m_pager->setCommitVersion(latest);
LogicalPageID newQueuePage = wait(self->m_pager->newPageID());
self->m_lazyClearQueue.create(self->m_pager, newQueuePage, "LazyClearQueue");
self->m_header.lazyDeleteQueue = self->m_lazyClearQueue.getState();
self->m_pager->setMetaKey(self->m_header.asKeyRef());
wait(self->m_pager->commit());
debug_printf("Committed initial commit.\n");
} else {
self->m_header.fromKeyRef(meta);
self->m_lazyClearQueue.recover(self->m_pager, self->m_header.lazyDeleteQueue, "LazyClearQueueRecovered");
}
debug_printf("Recovered btree at version %" PRId64 ": %s\n", latest, self->m_header.toString().c_str());
self->m_lastCommittedVersion = latest;
self->m_lazyClearActor = incrementalLazyClear(self);
return Void();
}
Future<Void> init() override { return m_init; }
virtual ~VersionedBTree() {
// This probably shouldn't be called directly (meaning deleting an instance directly) but it should be safe,
// it will cancel init and commit and leave the pager alive but with potentially an incomplete set of
// uncommitted writes so it should not be committed.
m_init.cancel();
m_latestCommit.cancel();
}
Reference<IStoreCursor> readAtVersion(Version v) override {
// Only committed versions can be read.
ASSERT(v <= m_lastCommittedVersion);
Reference<IPagerSnapshot> snapshot = m_pager->getReadSnapshot(v);
// This is a ref because snapshot will continue to hold the metakey value memory
KeyRef m = snapshot->getMetaKey();
// Currently all internal records generated in the write path are at version 0
return Reference<IStoreCursor>(new Cursor(snapshot, ((MetaKey*)m.begin())->root.get(), (Version)0));
}
// Must be nondecreasing
void setWriteVersion(Version v) override {
ASSERT(v > m_lastCommittedVersion);
// If there was no current mutation buffer, create one in the buffer map and update m_pBuffer
if (m_pBuffer == nullptr) {
// When starting a new mutation buffer its start version must be greater than the last write version
ASSERT(v > m_writeVersion);
m_pBuffer = &m_mutationBuffers[v];
} else {
// It's OK to set the write version to the same version repeatedly so long as m_pBuffer is not null
ASSERT(v >= m_writeVersion);
}
m_writeVersion = v;
}
Future<Void> commit() override {
if (m_pBuffer == nullptr)
return m_latestCommit;
return commit_impl(this);
}
ACTOR static Future<Void> clearAllAndCheckSanity_impl(VersionedBTree* self) {
ASSERT(g_network->isSimulated());
debug_printf("Clearing tree.\n");
self->setWriteVersion(self->getLatestVersion() + 1);
self->clear(KeyRangeRef(dbBegin.key, dbEnd.key));
wait(self->commit());
// Loop commits until the the lazy delete queue is completely processed.
loop {
wait(self->commit());
// If the lazy delete queue is completely processed then the last time the lazy delete actor
// was started it, after the last commit, it would exist immediately and do no work, so its
// future would be ready and its value would be 0.
if (self->m_lazyClearActor.isReady() && self->m_lazyClearActor.get() == 0) {
break;
}
self->setWriteVersion(self->getLatestVersion() + 1);
}
// Forget all but the latest version of the tree.
debug_printf("Discarding all old versions.\n");
self->setOldestVersion(self->getLastCommittedVersion());
self->setWriteVersion(self->getLatestVersion() + 1);
wait(self->commit());
// The lazy delete queue should now be empty and contain only the new page to start writing to
// on the next commit.
LazyClearQueueT::QueueState s = self->m_lazyClearQueue.getState();
ASSERT(s.numEntries == 0);
ASSERT(s.numPages == 1);
// The btree should now be a single non-oversized root page.
ASSERT(self->m_header.height == 1);
ASSERT(self->m_header.root.count == 1);
// From the pager's perspective the only pages that should be in use are the btree root and
// the previously mentioned lazy delete queue page.
int64_t userPageCount = wait(self->m_pager->getUserPageCount());
ASSERT(userPageCount == 2);
return Void();
}
Future<Void> clearAllAndCheckSanity() { return clearAllAndCheckSanity_impl(this); }
private:
// Represents a change to a single key - set, clear, or atomic op
struct SingleKeyMutation {
// Clear
SingleKeyMutation() : op(MutationRef::ClearRange) {}
// Set
SingleKeyMutation(Value val) : op(MutationRef::SetValue), value(val) {}
// Atomic Op
SingleKeyMutation(MutationRef::Type op, Value val) : op(op), value(val) {}
MutationRef::Type op;
Value value;
inline bool isClear() const { return op == MutationRef::ClearRange; }
inline bool isSet() const { return op == MutationRef::SetValue; }
inline bool isAtomicOp() const { return !isSet() && !isClear(); }
inline bool equalToSet(ValueRef val) { return isSet() && value == val; }
inline RedwoodRecordRef toRecord(KeyRef userKey, Version version) const {
// No point in serializing an atomic op, it needs to be coalesced to a real value.
ASSERT(!isAtomicOp());
if (isClear())
return RedwoodRecordRef(userKey, version);
return RedwoodRecordRef(userKey, version, value);
}
std::string toString() const { return format("op=%d val='%s'", op, printable(value).c_str()); }
};
struct RangeMutation {
RangeMutation() : boundaryChanged(false), clearAfterBoundary(false) {}
bool boundaryChanged;
Optional<ValueRef> boundaryValue; // Not present means cleared
bool clearAfterBoundary;
bool boundaryCleared() const { return boundaryChanged && !boundaryValue.present(); }
// Returns true if this RangeMutation doesn't actually mutate anything
bool noChanges() const { return !boundaryChanged && !clearAfterBoundary; }
void clearBoundary() {
boundaryChanged = true;
boundaryValue.reset();
}
void clearAll() {
clearBoundary();
clearAfterBoundary = true;
}
void setBoundaryValue(ValueRef v) {
boundaryChanged = true;
boundaryValue = v;
}
bool boundarySet() const { return boundaryChanged && boundaryValue.present(); }
std::string toString() const {
return format("boundaryChanged=%d clearAfterBoundary=%d boundaryValue=%s",
boundaryChanged,
clearAfterBoundary,
::toString(boundaryValue).c_str());
}
};
public:
#include "fdbserver/ArtMutationBuffer.h"
struct MutationBufferStdMap {
MutationBufferStdMap() {
// Create range representing the entire keyspace. This reduces edge cases to applying mutations
// because now all existing keys are within some range in the mutation map.
mutations[dbBegin.key];
// Setting the dbEnd key to be cleared prevents having to treat a range clear to dbEnd as a special
// case in order to avoid traversing down the rightmost edge of the tree.
mutations[dbEnd.key].clearBoundary();
}
private:
typedef std::map<KeyRef, RangeMutation> MutationsT;
Arena arena;
MutationsT mutations;
public:
struct iterator : public MutationsT::iterator {
typedef MutationsT::iterator Base;
iterator() = default;
iterator(const MutationsT::iterator& i) : Base(i) {}
const KeyRef& key() { return (*this)->first; }
RangeMutation& mutation() { return (*this)->second; }
};
struct const_iterator : public MutationsT::const_iterator {
typedef MutationsT::const_iterator Base;
const_iterator() = default;
const_iterator(const MutationsT::const_iterator& i) : Base(i) {}
const_iterator(const MutationsT::iterator& i) : Base(i) {}
const KeyRef& key() { return (*this)->first; }
const RangeMutation& mutation() { return (*this)->second; }
};
// Return a T constructed in arena
template <typename T>
T copyToArena(const T& object) {
return T(arena, object);
}
const_iterator upper_bound(const KeyRef& k) const { return mutations.upper_bound(k); }
const_iterator lower_bound(const KeyRef& k) const { return mutations.lower_bound(k); }
// erase [begin, end) from the mutation map
void erase(const const_iterator& begin, const const_iterator& end) { mutations.erase(begin, end); }
// Find or create a mutation buffer boundary for bound and return an iterator to it
iterator insert(KeyRef boundary) {
// Find the first split point in buffer that is >= key
// Since the initial state of the mutation buffer contains the range '' through
// the maximum possible key, our search had to have found something so we
// can assume the iterator is valid.
iterator ib = mutations.lower_bound(boundary);
// If we found the boundary we are looking for, return its iterator
if (ib.key() == boundary) {
return ib;
}
// ib is our insert hint. Copy boundary into arena and insert boundary into buffer
boundary = KeyRef(arena, boundary);
ib = mutations.insert(ib, { boundary, RangeMutation() });
// ib is certainly > begin() because it is guaranteed that the empty string
// boundary exists and the only way to have found that is to look explicitly
// for it in which case we would have returned above.
iterator iPrevious = ib;
--iPrevious;
// If the range we just divided was being cleared, then the dividing boundary key and range after it must
// also be cleared
if (iPrevious.mutation().clearAfterBoundary) {
ib.mutation().clearAll();
}
return ib;
}
};
#define USE_ART_MUTATION_BUFFER 1
#ifdef USE_ART_MUTATION_BUFFER
typedef struct MutationBufferART MutationBuffer;
#else
typedef struct MutationBufferStdMap MutationBuffer;
#endif
private:
/* Mutation Buffer Overview
*
* This structure's organization is meant to put pending updates for the btree in an order
* that makes it efficient to query all pending mutations across all pending versions which are
* relevant to a particular subtree of the btree.
*
* At the top level, it is a map of the start of a range being modified to a RangeMutation.
* The end of the range is map key (which is the next range start in the map).
*
* - The buffer starts out with keys '' and endKVV.key already populated.
*
* - When a new key is inserted into the buffer map, it is by definition
* splitting an existing range so it should take on the rangeClearVersion of
* the immediately preceding key which is the start of that range
*
* - Keys are inserted into the buffer map for every individual operation (set/clear/atomic)
* key and for both the start and end of a range clear.
*
* - To apply a single clear, add it to the individual ops only if the last entry is not also a clear.
*
* - To apply a range clear, after inserting the new range boundaries do the following to the start
* boundary and all successive boundaries < end
* - set the range clear version if not already set
* - add a clear to the startKeyMutations if the final entry is not a clear.
*
* - Note that there are actually TWO valid ways to represent
* set c = val1 at version 1
* clear c\x00 to z at version 2
* with this model. Either
* c = { rangeClearVersion = 2, startKeyMutations = { 1 => val1 }
* z = { rangeClearVersion = <not present>, startKeyMutations = {}
* OR
* c = { rangeClearVersion = <not present>, startKeyMutations = { 1 => val1 }
* c\x00 = { rangeClearVersion = 2, startKeyMutations = { 2 => <not present> }
* z = { rangeClearVersion = <not present>, startKeyMutations = {}
*
* This is because the rangeClearVersion applies to a range begining with the first
* key AFTER the start key, so that the logic for reading the start key is more simple
* as it only involves consulting startKeyMutations. When adding a clear range, the
* boundary key insert/split described above is valid, and is what is currently done,
* but it would also be valid to see if the last key before startKey is equal to
* keyBefore(startKey), and if so that mutation buffer boundary key can be used instead
* without adding an additional key to the buffer.
* TODO: A possible optimization here could be to only use existing btree leaf page boundaries as keys,
* with mutation point keys being stored in an unsorted strucutre under those boundary map keys,
* to be sorted later just before being merged into the existing leaf page.
*/
IPager2* m_pager;
MutationBuffer* m_pBuffer;
std::map<Version, MutationBuffer> m_mutationBuffers;
Version m_writeVersion;
Version m_lastCommittedVersion;
Version m_newOldestVersion;
Reference<FlowLock> m_commitReadLock;
Future<Void> m_latestCommit;
Future<Void> m_init;
std::string m_name;
int m_blockSize;
std::unordered_map<LogicalPageID, ParentInfo> parents;
ParentInfoMapT childUpdateTracker;
// MetaKey changes size so allocate space for it to expand into. FIXME: Steve is fixing this to be dynamically
// sized.
union {
uint8_t headerSpace[sizeof(MetaKey) + sizeof(LogicalPageID) * 200];
MetaKey m_header;
};
LazyClearQueueT m_lazyClearQueue;
Future<int> m_lazyClearActor;
bool m_lazyClearStop;
// Describes a range of a vector of records that should be built into a BTreePage
struct PageToBuild {
PageToBuild(int index, int blockSize)
: startIndex(index), count(0), pageSize(blockSize),
bytesLeft(blockSize - sizeof(BTreePage) - sizeof(BTreePage::BinaryTree)),
largeDeltaTree(pageSize > BTreePage::BinaryTree::SmallSizeLimit), blockSize(blockSize), blockCount(1),
kvBytes(0) {}
int startIndex; // Index of the first record
int count; // Number of records added to the page
int pageSize; // Page size required to hold a BTreePage of the added records, which is a multiple of blockSize
int bytesLeft; // Bytes in pageSize that are unused by the BTreePage so far
bool largeDeltaTree; // Whether or not the DeltaTree in the generated page is in the 'large' size range
int blockSize; // Base block size by which pageSize can be incremented
int blockCount; // The number of blocks in pageSize
int kvBytes; // The amount of user key/value bytes added to the page
// Number of bytes used by the generated/serialized BTreePage
int size() const { return pageSize - bytesLeft; }
// Used fraction of pageSize bytes
double usedFraction() const { return (double)size() / pageSize; }
// Unused fraction of pageSize bytes
double slackFraction() const { return (double)bytesLeft / pageSize; }
// Fraction of PageSize in use by key or value string bytes, disregarding all overhead including string sizes
double kvFraction() const { return (double)kvBytes / pageSize; }
// Index of the last record to be included in this page
int lastIndex() const { return endIndex() - 1; }
// Index of the first record NOT included in this page
int endIndex() const { return startIndex + count; }
std::string toString() const {
return format(
"{start=%d count=%d used %d/%d bytes (%.2f%% slack) kvBytes=%d blocks=%d blockSize=%d large=%d}",
startIndex,
count,
size(),
pageSize,
slackFraction() * 100,
kvBytes,
blockCount,
blockSize,
largeDeltaTree);
}
// Move an item from a to b if a has 2 or more items and the item fits in b
// a and b must be consecutive pages from the same array of records
static bool shiftItem(PageToBuild& a, PageToBuild& b, int deltaSize, int kvBytes) {
if (a.count < 2) {
return false;
}
// Size of the nodes in A and B, respectively
int aNodeSize = deltaSize + BTreePage::BinaryTree::Node::headerSize(a.largeDeltaTree);
int bNodeSize = deltaSize + BTreePage::BinaryTree::Node::headerSize(b.largeDeltaTree);
if (b.bytesLeft < bNodeSize) {
return false;
}
--a.count;
++b.count;
--b.startIndex;
a.bytesLeft += aNodeSize;
b.bytesLeft -= bNodeSize;
a.kvBytes -= kvBytes;
b.kvBytes += kvBytes;
return true;
}
// Try to add a record of the given delta size to the page.
// If force is true, the page will be expanded to make the record fit if needed.
// Return value is whether or not the record was added to the page.
bool addRecord(const RedwoodRecordRef& rec, int deltaSize, bool force) {
int nodeSize = deltaSize + BTreePage::BinaryTree::Node::headerSize(largeDeltaTree);
// If the record doesn't fit and the page can't be expanded then return false
if (nodeSize > bytesLeft && !force) {
return false;
}
++count;
bytesLeft -= nodeSize;
kvBytes += rec.kvBytes();
// If needed, expand page so that record fits.
// This is a loop because the first expansion may increase per-node overhead which could
// then require a second expansion.
while (bytesLeft < 0) {
int newBlocks = (-bytesLeft + blockSize - 1) / blockSize;
int extraSpace = newBlocks * blockSize;
blockCount += newBlocks;
bytesLeft += extraSpace;
pageSize += extraSpace;
// If size has moved into the "large" range then every node has gotten bigger so adjust bytesLeft
if (!largeDeltaTree && pageSize > BTreePage::BinaryTree::SmallSizeLimit) {
largeDeltaTree = true;
bytesLeft -= (count * BTreePage::BinaryTree::LargeTreePerNodeExtraOverhead);
}
}
return true;
}
};
// Scans a vector of records and decides on page split points, returning a vector of 1+ pages to build
static std::vector<PageToBuild> splitPages(const RedwoodRecordRef* lowerBound,
const RedwoodRecordRef* upperBound,
int prefixLen,
VectorRef<RedwoodRecordRef> records,
int height,
int blockSize) {
debug_printf("splitPages height=%d records=%d lowerBound=%s upperBound=%s\n",
height,
records.size(),
lowerBound->toString(false).c_str(),
upperBound->toString(false).c_str());
ASSERT(!records.empty());
// Leaves can have just one record if it's large, but internal pages should have at least 4
int minRecords = height == 1 ? 1 : 4;
double maxSlack = SERVER_KNOBS->REDWOOD_PAGE_REBUILD_MAX_SLACK;
std::vector<PageToBuild> pages;
// deltaSizes contains pair-wise delta sizes for [lowerBound, records..., upperBound]
std::vector<int> deltaSizes(records.size() + 1);
deltaSizes.front() = records.front().deltaSize(*lowerBound, prefixLen, true);
deltaSizes.back() = records.back().deltaSize(*upperBound, prefixLen, true);
for (int i = 1; i < records.size(); ++i) {
deltaSizes[i] = records[i].deltaSize(records[i - 1], prefixLen, true);
}
PageToBuild p(0, blockSize);
for (int i = 0; i < records.size(); ++i) {
bool force = p.count < minRecords || p.slackFraction() > maxSlack;
debug_printf(
" before addRecord i=%d records=%d deltaSize=%d kvSize=%d force=%d pageToBuild=%s record=%s",
i,
records.size(),
deltaSizes[i],
records[i].kvBytes(),
force,
p.toString().c_str(),
records[i].toString(height == 1).c_str());
if (!p.addRecord(records[i], deltaSizes[i], force)) {
pages.push_back(p);
p = PageToBuild(p.endIndex(), blockSize);
p.addRecord(records[i], deltaSizes[i], true);
}
}
if (p.count > 0) {
pages.push_back(p);
}
debug_printf(" Before shift: %s\n", ::toString(pages).c_str());
// If page count is > 1, try to balance slack between last two pages
// The buggify disables this balancing as this will result in more edge
// cases of pages with very few records.
if (pages.size() > 1 && !BUGGIFY) {
PageToBuild& a = pages[pages.size() - 2];
PageToBuild& b = pages.back();
// While the last page page has too much slack and the second to last page
// has more than the minimum record count, shift a record from the second
// to last page to the last page.
while (b.slackFraction() > maxSlack && a.count > minRecords) {
int i = a.lastIndex();
if (!PageToBuild::shiftItem(a, b, deltaSizes[i], records[i].kvBytes())) {
break;
}
debug_printf(" After shifting i=%d: a=%s b=%s\n", i, a.toString().c_str(), b.toString().c_str());
}
}
return pages;
}
// Writes entries to 1 or more pages and return a vector of boundary keys with their ArenaPage(s)
ACTOR static Future<Standalone<VectorRef<RedwoodRecordRef>>> writePages(VersionedBTree* self,
const RedwoodRecordRef* lowerBound,
const RedwoodRecordRef* upperBound,
VectorRef<RedwoodRecordRef> entries,
int height,
Version v,
BTreePageIDRef previousID) {
ASSERT(entries.size() > 0);
state Standalone<VectorRef<RedwoodRecordRef>> records;
// All records share the prefix shared by the lower and upper boundaries
state int prefixLen = lowerBound->getCommonPrefixLen(*upperBound);
state std::vector<PageToBuild> pagesToBuild =
splitPages(lowerBound, upperBound, prefixLen, entries, height, self->m_blockSize);
debug_printf("splitPages returning %s\n", toString(pagesToBuild).c_str());
// Lower bound of the page being added to
state RedwoodRecordRef pageLowerBound = lowerBound->withoutValue();
state RedwoodRecordRef pageUpperBound;
state int pageIndex;
for (pageIndex = 0; pageIndex < pagesToBuild.size(); ++pageIndex) {
auto& p = pagesToBuild[pageIndex];
debug_printf("building page %d of %d %s\n", pageIndex + 1, pagesToBuild.size(), p.toString().c_str());
ASSERT(p.count != 0);
// For internal pages, skip first entry if child link is null. Such links only exist
// to maintain a borrow-able prefix for the previous subtree after a subtree deletion.
// If the null link falls on a new page post-split, then the pageLowerBound of the page
// being built now will serve as the previous subtree's upper boundary as it is the same
// key as entries[p.startIndex] and there is no need to actually store the null link in
// the new page.
if (height != 1 && !entries[p.startIndex].value.present()) {
p.kvBytes -= entries[p.startIndex].key.size();
++p.startIndex;
--p.count;
debug_printf("Skipping first null record, new count=%d\n", p.count);
// If the page is now empty then it must be the last page in pagesToBuild, otherwise there would
// be more than 1 item since internal pages need to have multiple children. While there is no page
// to be built here, a record must be added to the output set because the upper boundary of the last
// page built does not match the upper boundary of the original page that this call to writePages() is
// replacing. Put another way, the upper boundary of the rightmost page of the page set that was just
// built does not match the upper boundary of the original page that the page set is replacing, so
// adding the extra null link fixes this.
if (p.count == 0) {
ASSERT(pageIndex == pagesToBuild.size() - 1);
records.push_back_deep(records.arena(), pageUpperBound);
break;
}
}
// Use the next entry as the upper bound, or upperBound if there are no more entries beyond this page
int endIndex = p.endIndex();
bool lastPage = endIndex == entries.size();
pageUpperBound = lastPage ? upperBound->withoutValue() : entries[endIndex].withoutValue();
// If this is a leaf page, and not the last one to be written, shorten the upper boundary
if (!lastPage && height == 1) {
int commonPrefix = pageUpperBound.getCommonPrefixLen(entries[endIndex - 1], prefixLen);
pageUpperBound.truncate(commonPrefix + 1);
}
state std::vector<Reference<ArenaPage>> pages;
BTreePage* btPage;
if (p.blockCount == 1) {
Reference<ArenaPage> page = self->m_pager->newPageBuffer();
btPage = (BTreePage*)page->mutate();
pages.push_back(std::move(page));
} else {
ASSERT(p.blockCount > 1);
btPage = (BTreePage*)new uint8_t[p.pageSize];
}
btPage->height = height;
btPage->kvBytes = p.kvBytes;
debug_printf("Building tree for %s\nlower: %s\nupper: %s\n",
p.toString().c_str(),
pageLowerBound.toString(false).c_str(),
pageUpperBound.toString(false).c_str());
int deltaTreeSpace = p.pageSize - sizeof(BTreePage);
state int written = btPage->tree().build(
deltaTreeSpace, &entries[p.startIndex], &entries[endIndex], &pageLowerBound, &pageUpperBound);
if (written > deltaTreeSpace) {
debug_printf("ERROR: Wrote %d bytes to page %s deltaTreeSpace=%d\n",
written,
p.toString().c_str(),
deltaTreeSpace);
TraceEvent(SevError, "RedwoodDeltaTreeOverflow")
.detail("PageSize", p.pageSize)
.detail("BytesWritten", written);
ASSERT(false);
}
auto& metrics = g_redwoodMetrics.level(btPage->height);
metrics.pageBuild += 1;
metrics.pageBuildExt += p.blockCount - 1;
metrics.buildFillPct += p.usedFraction();
metrics.buildStoredPct += p.kvFraction();
metrics.buildItemCount += p.count;
// Create chunked pages
// TODO: Avoid copying page bytes, but this is not trivial due to how pager checksums are currently handled.
if (p.blockCount != 1) {
// Mark the slack in the page buffer as defined
VALGRIND_MAKE_MEM_DEFINED(((uint8_t*)btPage) + written, (p.blockCount * p.blockSize) - written);
const uint8_t* rptr = (const uint8_t*)btPage;
for (int b = 0; b < p.blockCount; ++b) {
Reference<ArenaPage> page = self->m_pager->newPageBuffer();
memcpy(page->mutate(), rptr, p.blockSize);
rptr += p.blockSize;
pages.push_back(std::move(page));
}
delete[](uint8_t*) btPage;
}
// Write this btree page, which is made of 1 or more pager pages.
state BTreePageIDRef childPageID;
state int k;
// If we are only writing 1 page and it has the same BTreePageID size as the original then try to reuse the
// LogicalPageIDs in previousID and try to update them atomically.
if (pagesToBuild.size() == 1 && previousID.size() == pages.size()) {
for (k = 0; k < pages.size(); ++k) {
LogicalPageID id = wait(self->m_pager->atomicUpdatePage(previousID[k], pages[k], v));
childPageID.push_back(records.arena(), id);
}
} else {
// Either the original page is being split, or it's not but it has changed BTreePageID size.
// Either way, there is no point in reusing any of the original page IDs because the parent
// must be rewritten anyway to count for the change in child count or child links.
// Free the old IDs, but only once (before the first output record is added).
if (records.empty()) {
self->freeBTreePage(previousID, v);
}
for (k = 0; k < pages.size(); ++k) {
LogicalPageID id = wait(self->m_pager->newPageID());
self->m_pager->updatePage(id, pages[k]);
childPageID.push_back(records.arena(), id);
}
}
wait(yield());
if (REDWOOD_DEBUG) {
auto& p = pagesToBuild[pageIndex];
debug_printf("Wrote %s original=%s deltaTreeSize=%d for %s\nlower: %s\nupper: %s\n",
toString(childPageID).c_str(),
toString(previousID).c_str(),
written,
p.toString().c_str(),
pageLowerBound.toString(false).c_str(),
pageUpperBound.toString(false).c_str());
for (int j = p.startIndex; j < p.endIndex(); ++j) {
debug_printf(" %3d: %s\n", j, entries[j].toString(height == 1).c_str());
}
ASSERT(pageLowerBound.key <= pageUpperBound.key);
}
// Push a new record onto the results set, without the child page, copying it into the records arena
records.push_back_deep(records.arena(), pageLowerBound.withoutValue());
// Set the child page value of the inserted record to childPageID, which has already been allocated in
// records.arena() above
records.back().setChildPage(childPageID);
pageLowerBound = pageUpperBound;
}
return records;
}
ACTOR static Future<Standalone<VectorRef<RedwoodRecordRef>>>
buildNewRoot(VersionedBTree* self, Version version, Standalone<VectorRef<RedwoodRecordRef>> records, int height) {
debug_printf("buildNewRoot start version %" PRId64 ", %lu records\n", version, records.size());
// While there are multiple child pages for this version we must write new tree levels.
while (records.size() > 1) {
self->m_header.height = ++height;
Standalone<VectorRef<RedwoodRecordRef>> newRecords =
wait(writePages(self, &dbBegin, &dbEnd, records, height, version, BTreePageIDRef()));
debug_printf("Wrote a new root level at version %" PRId64 " height %d size %lu pages\n",
version,
height,
newRecords.size());
records = newRecords;
}
return records;
}
// Try to evict a BTree page from the pager cache.
// Returns true if, at the end of the call, the page is no longer in cache,
// so the caller can assume its ArenaPage reference is the only one.
bool tryEvictPage(IPagerSnapshot* pager, BTreePageIDRef id) {
// If it's an oversized page, currently it cannot be in the cache
if (id.size() > 0) {
return true;
}
return pager->tryEvictPage(id.front());
}
ACTOR static Future<Reference<const ArenaPage>> readPage(Reference<IPagerSnapshot> snapshot,
BTreePageIDRef id,
const RedwoodRecordRef* lowerBound,
const RedwoodRecordRef* upperBound,
bool forLazyClear = false,
bool cacheable = true,
bool* fromCache = nullptr) {
if (!forLazyClear) {
debug_printf("readPage() op=read %s @%" PRId64 " lower=%s upper=%s\n",
toString(id).c_str(),
snapshot->getVersion(),
lowerBound->toString(false).c_str(),
upperBound->toString(false).c_str());
} else {
debug_printf(
"readPage() op=readForDeferredClear %s @%" PRId64 " \n", toString(id).c_str(), snapshot->getVersion());
}
wait(yield());
state Reference<const ArenaPage> page;
if (id.size() == 1) {
Reference<const ArenaPage> p = wait(snapshot->getPhysicalPage(id.front(), cacheable, false, fromCache));
page = std::move(p);
} else {
ASSERT(!id.empty());
std::vector<Future<Reference<const ArenaPage>>> reads;
for (auto& pageID : id) {
reads.push_back(snapshot->getPhysicalPage(pageID, cacheable, false));
}
std::vector<Reference<const ArenaPage>> pages = wait(getAll(reads));
// TODO: Cache reconstituted super pages somehow, perhaps with help from the Pager.
page = ArenaPage::concatPages(pages);
// In the current implementation, SuperPages are never present in the cache
if (fromCache != nullptr) {
*fromCache = false;
}
}
debug_printf("readPage() op=readComplete %s @%" PRId64 " \n", toString(id).c_str(), snapshot->getVersion());
const BTreePage* pTreePage = (const BTreePage*)page->begin();
auto& metrics = g_redwoodMetrics.level(pTreePage->height);
metrics.pageRead += 1;
metrics.pageReadExt += (id.size() - 1);
if (!forLazyClear && page->userData == nullptr) {
debug_printf("readPage() Creating Mirror for %s @%" PRId64 " lower=%s upper=%s\n",
toString(id).c_str(),
snapshot->getVersion(),
lowerBound->toString(false).c_str(),
upperBound->toString(false).c_str());
page->userData = new BTreePage::BinaryTree::Mirror(&pTreePage->tree(), lowerBound, upperBound);
page->userDataDestructor = [](void* ptr) { delete (BTreePage::BinaryTree::Mirror*)ptr; };
}
if (!forLazyClear) {
debug_printf("readPage() %s\n",
pTreePage->toString(false, id, snapshot->getVersion(), lowerBound, upperBound).c_str());
}
return std::move(page);
}
static void preLoadPage(IPagerSnapshot* snapshot, BTreePageIDRef id) {
g_redwoodMetrics.btreeLeafPreload += 1;
g_redwoodMetrics.btreeLeafPreloadExt += (id.size() - 1);
for (auto pageID : id) {
snapshot->getPhysicalPage(pageID, true, true);
}
}
void freeBTreePage(BTreePageIDRef btPageID, Version v) {
// Free individual pages at v
for (LogicalPageID id : btPageID) {
m_pager->freePage(id, v);
}
}
// Write new version of pageID at version v using page as its data.
// Attempts to reuse original id(s) in btPageID, returns BTreePageID.
ACTOR static Future<BTreePageIDRef> updateBTreePage(VersionedBTree* self,
BTreePageIDRef oldID,
Arena* arena,
Reference<ArenaPage> page,
Version writeVersion) {
state BTreePageIDRef newID;
newID.resize(*arena, oldID.size());
if (oldID.size() == 1) {
LogicalPageID id = wait(self->m_pager->atomicUpdatePage(oldID.front(), page, writeVersion));
newID.front() = id;
} else {
state std::vector<Reference<ArenaPage>> pages;
const uint8_t* rptr = page->begin();
int bytesLeft = page->size();
while (bytesLeft > 0) {
Reference<ArenaPage> p = self->m_pager->newPageBuffer();
int blockSize = p->size();
memcpy(p->mutate(), rptr, blockSize);
rptr += blockSize;
bytesLeft -= blockSize;
pages.push_back(p);
}
ASSERT(pages.size() == oldID.size());
// Write pages, trying to reuse original page IDs
state int i = 0;
for (; i < pages.size(); ++i) {
LogicalPageID id = wait(self->m_pager->atomicUpdatePage(oldID[i], pages[i], writeVersion));
newID[i] = id;
}
}
return newID;
}
// Copy page and initialize a Mirror for reading it.
Reference<ArenaPage> cloneForUpdate(Reference<const ArenaPage> page) {
Reference<ArenaPage> newPage = page->cloneContents();
auto oldMirror = (const BTreePage::BinaryTree::Mirror*)page->userData;
auto newBTPage = (BTreePage*)newPage->mutate();
newPage->userData =
new BTreePage::BinaryTree::Mirror(&newBTPage->tree(), oldMirror->lowerBound(), oldMirror->upperBound());
newPage->userDataDestructor = [](void* ptr) { delete (BTreePage::BinaryTree::Mirror*)ptr; };
return newPage;
}
// Each call to commitSubtree() will pass most of its arguments via a this structure because the caller
// will need access to these parameters after commitSubtree() is done.
struct InternalPageSliceUpdate {
// The logical range for the subtree's contents. Due to subtree clears, these boundaries may not match
// the lower/upper bounds needed to decode the page.
// Subtree clears can cause the boundaries for decoding the page to be more restrictive than the subtree's
// logical boundaries. When a subtree is fully cleared, the link to it is replaced with a null link, but
// the key boundary remains in tact to support decoding of the previous subtree.
const RedwoodRecordRef* subtreeLowerBound;
const RedwoodRecordRef* subtreeUpperBound;
// The lower/upper bound for decoding the root of the subtree
const RedwoodRecordRef* decodeLowerBound;
const RedwoodRecordRef* decodeUpperBound;
bool boundariesNormal() const {
// If the decode upper boundary is the subtree upper boundary the pointers will be the same
// For the lower boundary, if the pointers are not the same there is still a possibility
// that the keys are the same. This happens for the first remaining subtree of an internal page
// after the prior subtree(s) were cleared.
return (decodeUpperBound == subtreeUpperBound) &&
(decodeLowerBound == subtreeLowerBound || decodeLowerBound->sameExceptValue(*subtreeLowerBound));
}
// The record range of the subtree slice is cBegin to cEnd
// cBegin.get().getChildPage() is guaranteed to be valid
// cEnd can be
// - the next record which also has a child page
// - the next-next record which has a child page because the next record does not and
// only existed to provide the correct upper bound for decoding cBegin's child page
// - a later record with a valid child page, because this slice represents a range of
// multiple subtrees that are either all unchanged or all cleared.
// - invalid, because cBegin is the last child entry in the page or because the range
// being cleared or unchanged extends to the end of the page's entries
BTreePage::BinaryTree::Cursor cBegin;
BTreePage::BinaryTree::Cursor cEnd;
// The prefix length common to the entire logical subtree. Might be shorter than the length common to all
// actual items in the page.
int skipLen;
// Members below this point are "output" members, set by function calls from commitSubtree() once it decides
// what is happening with this slice of the tree.
// If true, present, the contents of newLinks should replace [cBegin, cEnd)
bool childrenChanged;
Standalone<VectorRef<RedwoodRecordRef>> newLinks;
// The upper boundary expected, if any, by the last child in either [cBegin, cEnd) or newLinks
// If the last record in the range has a null link then this will be null.
const RedwoodRecordRef* expectedUpperBound;
bool inPlaceUpdate;
// CommitSubtree will call one of the following three functions based on its exit path
// Subtree was cleared.
void cleared() {
inPlaceUpdate = false;
childrenChanged = true;
expectedUpperBound = nullptr;
}
// Page was updated in-place through edits and written to maybeNewID
void updatedInPlace(BTreePageIDRef maybeNewID, BTreePage* btPage, int capacity) {
inPlaceUpdate = true;
auto& metrics = g_redwoodMetrics.level(btPage->height);
metrics.pageModify += 1;
metrics.pageModifyExt += (maybeNewID.size() - 1);
metrics.modifyFillPct += (double)btPage->size() / capacity;
metrics.modifyStoredPct += (double)btPage->kvBytes / capacity;
metrics.modifyItemCount += btPage->tree().numItems;
// The boundaries can't have changed, but the child page link may have.
if (maybeNewID != decodeLowerBound->getChildPage()) {
// Add page's decode lower bound to newLinks set without its child page, intially
newLinks.push_back_deep(newLinks.arena(), decodeLowerBound->withoutValue());
// Set the child page ID, which has already been allocated in result.arena()
newLinks.back().setChildPage(maybeNewID);
childrenChanged = true;
} else {
childrenChanged = false;
}
// Expected upper bound remains unchanged.
}
// writePages() was used to build 1 or more replacement pages.
void rebuilt(Standalone<VectorRef<RedwoodRecordRef>> newRecords) {
inPlaceUpdate = false;
newLinks = newRecords;
childrenChanged = true;
// If the replacement records ended on a non-null child page, then the expect upper bound is
// the subtree upper bound since that is what would have been used for the page(s) rebuild,
// otherwise it is null.
expectedUpperBound = newLinks.back().value.present() ? subtreeUpperBound : nullptr;
}
// Get the first record for this range AFTER applying whatever changes were made
const RedwoodRecordRef* getFirstBoundary() const {
if (childrenChanged) {
if (newLinks.empty()) {
return nullptr;
}
return &newLinks.front();
}
return decodeLowerBound;
}
std::string toString() const {
std::string s;
s += format("SubtreeSlice: addr=%p skipLen=%d subtreeCleared=%d childrenChanged=%d inPlaceUpdate=%d\n",
this,
skipLen,
childrenChanged && newLinks.empty(),
childrenChanged,
inPlaceUpdate);
s += format("SubtreeLower: %s\n", subtreeLowerBound->toString(false).c_str());
s += format(" DecodeLower: %s\n", decodeLowerBound->toString(false).c_str());
s += format(" DecodeUpper: %s\n", decodeUpperBound->toString(false).c_str());
s += format("SubtreeUpper: %s\n", subtreeUpperBound->toString(false).c_str());
s += format("expectedUpperBound: %s\n",
expectedUpperBound ? expectedUpperBound->toString(false).c_str() : "(null)");
for (int i = 0; i < newLinks.size(); ++i) {
s += format(" %i: %s\n", i, newLinks[i].toString(false).c_str());
}
s.resize(s.size() - 1);
return s;
}
};
struct InternalPageModifier {
InternalPageModifier() {}
InternalPageModifier(BTreePage* p, BTreePage::BinaryTree::Mirror* m, bool updating, ParentInfo* parentInfo)
: btPage(p), m(m), updating(updating), changesMade(false), parentInfo(parentInfo) {}
bool updating;
BTreePage* btPage;
BTreePage::BinaryTree::Mirror* m;
Standalone<VectorRef<RedwoodRecordRef>> rebuild;
bool changesMade;
ParentInfo* parentInfo;
bool empty() const {
if (updating) {
return m->tree->numItems == 0;
} else {
return rebuild.empty();
}
}
// end is the cursor position of the first record of the unvisited child link range, which
// is needed if the insert requires switching from update to rebuild mode.
void insert(BTreePage::BinaryTree::Cursor end, const VectorRef<RedwoodRecordRef>& recs) {
int i = 0;
if (updating) {
// TODO: insert recs in a random order to avoid new subtree being entirely right child links
while (i != recs.size()) {
const RedwoodRecordRef& rec = recs[i];
debug_printf("internal page (updating) insert: %s\n", rec.toString(false).c_str());
if (!m->insert(rec)) {
debug_printf("internal page: failed to insert %s, switching to rebuild\n",
rec.toString(false).c_str());
// Update failed, so populate rebuild vector with everything up to but not including end, which
// may include items from recs that were already added.
auto c = end;
if (c.moveFirst()) {
rebuild.reserve(rebuild.arena(), c.mirror->tree->numItems);
while (c != end) {
debug_printf(" internal page rebuild: add %s\n", c.get().toString(false).c_str());
rebuild.push_back(rebuild.arena(), c.get());
c.moveNext();
}
}
updating = false;
break;
}
btPage->kvBytes += rec.kvBytes();
++i;
}
}
// Not updating existing page so just add recs to rebuild vector
if (!updating) {
rebuild.reserve(rebuild.arena(), rebuild.size() + recs.size());
while (i != recs.size()) {
const RedwoodRecordRef& rec = recs[i];
debug_printf("internal page (rebuilding) insert: %s\n", rec.toString(false).c_str());
rebuild.push_back(rebuild.arena(), rec);
++i;
}
}
}
void keep(BTreePage::BinaryTree::Cursor begin, BTreePage::BinaryTree::Cursor end) {
if (!updating) {
while (begin != end) {
debug_printf("internal page (rebuilding) keeping: %s\n", begin.get().toString(false).c_str());
rebuild.push_back(rebuild.arena(), begin.get());
begin.moveNext();
}
} else if (REDWOOD_DEBUG) {
while (begin != end) {
debug_printf("internal page (updating) keeping: %s\n", begin.get().toString(false).c_str());
begin.moveNext();
}
}
}
// This must be called for each of the InternalPageSliceUpdates in sorted order.
void applyUpdate(InternalPageSliceUpdate& u, const RedwoodRecordRef* nextBoundary) {
debug_printf("applyUpdate nextBoundary=(%p) %s %s\n",
nextBoundary,
(nextBoundary != nullptr) ? nextBoundary->toString(false).c_str() : "",
u.toString().c_str());
// If the children changed, replace [cBegin, cEnd) with newLinks
if (u.childrenChanged) {
if (updating) {
auto c = u.cBegin;
while (c != u.cEnd) {
debug_printf("internal page (updating) erasing: %s\n", c.get().toString(false).c_str());
btPage->kvBytes -= c.get().kvBytes();
c.erase();
}
// [cBegin, cEnd) is now erased, and cBegin is invalid, so cEnd represents the end
// of the range that comes before any part of newLinks that can't be added if there
// is not enough space.
insert(u.cEnd, u.newLinks);
} else {
// Already in rebuild mode so the cursor parameter is meaningless
insert({}, u.newLinks);
}
// cBegin has been erased so interating from the first entry forward will never see cBegin to use as an
// endpoint.
changesMade = true;
} else {
if (u.inPlaceUpdate) {
for (auto id : u.decodeLowerBound->getChildPage()) {
parentInfo->pageUpdated(id);
}
}
keep(u.cBegin, u.cEnd);
}
// If there is an expected upper boundary for the next range after u
if (u.expectedUpperBound != nullptr) {
// Then if it does not match the next boundary then insert a dummy record
if (nextBoundary == nullptr ||
(nextBoundary != u.expectedUpperBound && !nextBoundary->sameExceptValue(*u.expectedUpperBound))) {
RedwoodRecordRef rec = u.expectedUpperBound->withoutValue();
debug_printf("applyUpdate adding dummy record %s\n", rec.toString(false).c_str());
insert(u.cEnd, { &rec, 1 });
changesMade = true;
}
}
}
};
ACTOR static Future<Void> commitSubtree(
VersionedBTree* self,
Reference<IPagerSnapshot> snapshot,
MutationBuffer* mutationBuffer,
BTreePageIDRef rootID,
bool isLeaf,
MutationBuffer::const_iterator mBegin, // greatest mutation boundary <= subtreeLowerBound->key
MutationBuffer::const_iterator mEnd, // least boundary >= subtreeUpperBound->key
InternalPageSliceUpdate* update) {
state std::string context;
if (REDWOOD_DEBUG) {
context = format("CommitSubtree(root=%s): ", toString(rootID).c_str());
}
debug_printf("%s %s\n", context.c_str(), update->toString().c_str());
if (REDWOOD_DEBUG) {
debug_printf("%s ---------MUTATION BUFFER SLICE ---------------------\n", context.c_str());
auto begin = mBegin;
while (1) {
debug_printf("%s Mutation: '%s': %s\n",
context.c_str(),
printable(begin.key()).c_str(),
begin.mutation().toString().c_str());
if (begin == mEnd) {
break;
}
++begin;
}
debug_printf("%s -------------------------------------\n", context.c_str());
}
state Version writeVersion = self->getLastCommittedVersion() + 1;
state Reference<FlowLock> commitReadLock = self->m_commitReadLock;
wait(commitReadLock->take());
state FlowLock::Releaser readLock(*commitReadLock);
state bool fromCache = false;
state Reference<const ArenaPage> page = wait(
readPage(snapshot, rootID, update->decodeLowerBound, update->decodeUpperBound, false, false, &fromCache));
readLock.release();
state BTreePage* btPage = (BTreePage*)page->begin();
ASSERT(isLeaf == btPage->isLeaf());
g_redwoodMetrics.level(btPage->height).pageCommitStart += 1;
// TODO: Decide if it is okay to update if the subtree boundaries are expanded. It can result in
// records in a DeltaTree being outside its decode boundary range, which isn't actually invalid
// though it is awkward to reason about.
state bool tryToUpdate = btPage->tree().numItems > 0 && update->boundariesNormal();
// If trying to update the page and the page reference points into the cache,
// we need to clone it so we don't modify the original version of the page.
// TODO: Refactor DeltaTree::Mirror so it can be shared between different versions of pages
if (tryToUpdate && fromCache) {
page = self->cloneForUpdate(page);
btPage = (BTreePage*)page->begin();
fromCache = false;
}
debug_printf(
"%s commitSubtree(): %s\n",
context.c_str(),
btPage->toString(false, rootID, snapshot->getVersion(), update->decodeLowerBound, update->decodeUpperBound)
.c_str());
state BTreePage::BinaryTree::Cursor cursor = getCursor(page);
if (REDWOOD_DEBUG) {
debug_printf("%s ---------MUTATION BUFFER SLICE ---------------------\n", context.c_str());
auto begin = mBegin;
while (1) {
debug_printf("%s Mutation: '%s': %s\n",
context.c_str(),
printable(begin.key()).c_str(),
begin.mutation().toString().c_str());
if (begin == mEnd) {
break;
}
++begin;
}
debug_printf("%s -------------------------------------\n", context.c_str());
}
// Leaf Page
if (isLeaf) {
bool updating = tryToUpdate;
bool changesMade = false;
// Couldn't make changes in place, so now do a linear merge and build new pages.
state Standalone<VectorRef<RedwoodRecordRef>> merged;
auto switchToLinearMerge = [&]() {
updating = false;
auto c = cursor;
c.moveFirst();
while (c != cursor) {
debug_printf("%s catch-up adding %s\n", context.c_str(), c.get().toString().c_str());
merged.push_back(merged.arena(), c.get());
c.moveNext();
}
};
// The first mutation buffer boundary has a key <= the first key in the page.
cursor.moveFirst();
debug_printf("%s Leaf page, applying changes.\n", context.c_str());
// Now, process each mutation range and merge changes with existing data.
bool firstMutationBoundary = true;
while (mBegin != mEnd) {
debug_printf("%s New mutation boundary: '%s': %s\n",
context.c_str(),
printable(mBegin.key()).c_str(),
mBegin.mutation().toString().c_str());
// Apply the change to the mutation buffer start boundary key only if
// - there actually is a change (whether a set or a clear, old records are to be removed)
// - either this is not the first boundary or it is but its key matches our lower bound key
bool applyBoundaryChange = mBegin.mutation().boundaryChanged &&
(!firstMutationBoundary || mBegin.key() == update->subtreeLowerBound->key);
firstMutationBoundary = false;
// Iterate over records for the mutation boundary key, keep them unless the boundary key was changed or
// we are not applying it
while (cursor.valid() && cursor.get().key == mBegin.key()) {
// If there were no changes to the key or we're not applying it
if (!applyBoundaryChange) {
// If not updating, add to the output set, otherwise skip ahead past the records for the
// mutation boundary
if (!updating) {
merged.push_back(merged.arena(), cursor.get());
debug_printf("%s Added %s [existing, boundary start]\n",
context.c_str(),
cursor.get().toString().c_str());
}
cursor.moveNext();
} else {
changesMade = true;
// If updating, erase from the page, otherwise do not add to the output set
if (updating) {
debug_printf("%s Erasing %s [existing, boundary start]\n",
context.c_str(),
cursor.get().toString().c_str());
btPage->kvBytes -= cursor.get().kvBytes();
cursor.erase();
} else {
debug_printf("%s Skipped %s [existing, boundary start]\n",
context.c_str(),
cursor.get().toString().c_str());
cursor.moveNext();
}
}
}
constexpr int maxHeightAllowed = 8;
// Write the new record(s) for the mutation boundary start key if its value has been set
// Clears of this key will have been processed above by not being erased from the updated page or
// excluded from the merge output
if (applyBoundaryChange && mBegin.mutation().boundarySet()) {
RedwoodRecordRef rec(mBegin.key(), 0, mBegin.mutation().boundaryValue.get());
changesMade = true;
// If updating, add to the page, else add to the output set
if (updating) {
if (cursor.mirror->insert(rec, update->skipLen, maxHeightAllowed)) {
btPage->kvBytes += rec.kvBytes();
debug_printf(
"%s Inserted %s [mutation, boundary start]\n", context.c_str(), rec.toString().c_str());
} else {
debug_printf("%s Insert failed for %s [mutation, boundary start]\n",
context.c_str(),
rec.toString().c_str());
switchToLinearMerge();
}
}
if (!updating) {
merged.push_back(merged.arena(), rec);
debug_printf(
"%s Added %s [mutation, boundary start]\n", context.c_str(), rec.toString().c_str());
}
}
// Before advancing the iterator, get whether or not the records in the following range must be removed
bool remove = mBegin.mutation().clearAfterBoundary;
// Advance to the next boundary because we need to know the end key for the current range.
++mBegin;
if (mBegin == mEnd) {
update->skipLen = 0;
}
debug_printf("%s Mutation range end: '%s'\n", context.c_str(), printable(mBegin.key()).c_str());
// Now handle the records up through but not including the next mutation boundary key
RedwoodRecordRef end(mBegin.key());
// If the records are being removed and we're not doing an in-place update
// OR if we ARE doing an update but the records are NOT being removed, then just skip them.
if (remove != updating) {
// If not updating, then the records, if any exist, are being removed. We don't know if there
// actually are any but we must assume there are.
if (!updating) {
changesMade = true;
}
debug_printf("%s Seeking forward to next boundary (remove=%d updating=%d) %s\n",
context.c_str(),
remove,
updating,
mBegin.key().toString().c_str());
cursor.seekGreaterThanOrEqual(end, update->skipLen);
} else {
// Otherwise we must visit the records. If updating, the visit is to erase them, and if doing a
// linear merge than the visit is to add them to the output set.
while (cursor.valid() && cursor.get().compare(end, update->skipLen) < 0) {
if (updating) {
debug_printf("%s Erasing %s [existing, boundary start]\n",
context.c_str(),
cursor.get().toString().c_str());
btPage->kvBytes -= cursor.get().kvBytes();
cursor.erase();
changesMade = true;
} else {
merged.push_back(merged.arena(), cursor.get());
debug_printf(
"%s Added %s [existing, middle]\n", context.c_str(), merged.back().toString().c_str());
cursor.moveNext();
}
}
}
}
// If there are still more records, they have the same key as the end boundary
if (cursor.valid()) {
// If the end boundary is changing, we must remove the remaining records in this page
bool remove = mEnd.mutation().boundaryChanged;
if (remove) {
changesMade = true;
}
// If we don't have to remove the records and we are updating, do nothing.
// If we do have to remove the records and we are not updating, do nothing.
if (remove != updating) {
debug_printf(
"%s Ignoring remaining records, remove=%d updating=%d\n", context.c_str(), remove, updating);
} else {
// If updating and the key is changing, we must visit the records to erase them.
// If not updating and the key is not changing, we must visit the records to add them to the output
// set.
while (cursor.valid()) {
if (updating) {
debug_printf(
"%s Erasing %s and beyond [existing, matches changed upper mutation boundary]\n",
context.c_str(),
cursor.get().toString().c_str());
btPage->kvBytes -= cursor.get().kvBytes();
cursor.erase();
} else {
merged.push_back(merged.arena(), cursor.get());
debug_printf(
"%s Added %s [existing, tail]\n", context.c_str(), merged.back().toString().c_str());
cursor.moveNext();
}
}
}
} else {
debug_printf("%s No records matching mutation buffer end boundary key\n", context.c_str());
}
// No changes were actually made. This could happen if the only mutations are clear ranges which do not
// match any records.
if (!changesMade) {
debug_printf("%s No changes were made during mutation merge, returning %s\n",
context.c_str(),
toString(*update).c_str());
return Void();
} else {
debug_printf(
"%s Changes were made, writing, but subtree may still be unchanged from parent's perspective.\n",
context.c_str());
}
writeVersion = self->getLastCommittedVersion() + 1;
if (updating) {
const BTreePage::BinaryTree& deltaTree = btPage->tree();
// If the tree is now empty, delete the page
if (deltaTree.numItems == 0) {
update->cleared();
self->freeBTreePage(rootID, writeVersion);
debug_printf("%s Page updates cleared all entries, returning %s\n",
context.c_str(),
toString(*update).c_str());
} else {
// Otherwise update it.
BTreePageIDRef newID = wait(self->updateBTreePage(
self, rootID, &update->newLinks.arena(), page.castTo<ArenaPage>(), writeVersion));
update->updatedInPlace(newID, btPage, newID.size() * self->m_blockSize);
debug_printf(
"%s Page updated in-place, returning %s\n", context.c_str(), toString(*update).c_str());
}
return Void();
}
// If everything in the page was deleted then this page should be deleted as of the new version
if (merged.empty()) {
update->cleared();
self->freeBTreePage(rootID, writeVersion);
debug_printf("%s All leaf page contents were cleared, returning %s\n",
context.c_str(),
toString(*update).c_str());
return Void();
}
// Rebuild new page(s).
state Standalone<VectorRef<RedwoodRecordRef>> entries = wait(writePages(self,
update->subtreeLowerBound,
update->subtreeUpperBound,
merged,
btPage->height,
writeVersion,
rootID));
// Put new links into update and tell update that pages were rebuilt
update->rebuilt(entries);
debug_printf("%s Merge complete, returning %s\n", context.c_str(), toString(*update).c_str());
return Void();
} else {
// Internal Page
std::vector<Future<Void>> recursions;
state std::vector<InternalPageSliceUpdate*> slices;
state Arena arena;
cursor.moveFirst();
bool first = true;
while (cursor.valid()) {
InternalPageSliceUpdate& u = *new (arena) InternalPageSliceUpdate();
slices.push_back(&u);
// At this point we should never be at a null child page entry because the first entry of a page
// can't be null and this loop will skip over null entries that come after non-null entries.
ASSERT(cursor.get().value.present());
// Subtree lower boundary is this page's subtree lower bound or cursor
u.cBegin = cursor;
u.decodeLowerBound = &cursor.get();
if (first) {
u.subtreeLowerBound = update->subtreeLowerBound;
first = false;
// mbegin is already the first mutation that could affect this subtree described by update
} else {
u.subtreeLowerBound = u.decodeLowerBound;
mBegin = mEnd;
// mBegin is either at or greater than subtreeLowerBound->key, which was the subtreeUpperBound->key
// for the previous subtree slice. But we need it to be at or *before* subtreeLowerBound->key
// so if mBegin.key() is not exactly the subtree lower bound key then decrement it.
if (mBegin.key() != u.subtreeLowerBound->key) {
--mBegin;
}
}
BTreePageIDRef pageID = cursor.get().getChildPage();
ASSERT(!pageID.empty());
// The decode upper bound is always the next key after the child link, or the decode upper bound for
// this page
if (cursor.moveNext()) {
u.decodeUpperBound = &cursor.get();
// If cursor record has a null child page then it exists only to preserve a previous
// subtree boundary that is now needed for reading the subtree at cBegin.
if (!cursor.get().value.present()) {
// If the upper bound is provided by a dummy record in [cBegin, cEnd) then there is no
// requirement on the next subtree range or the parent page to have a specific upper boundary
// for decoding the subtree.
u.expectedUpperBound = nullptr;
cursor.moveNext();
// If there is another record after the null child record, it must have a child page value
ASSERT(!cursor.valid() || cursor.get().value.present());
} else {
u.expectedUpperBound = u.decodeUpperBound;
}
} else {
u.decodeUpperBound = update->decodeUpperBound;
u.expectedUpperBound = update->decodeUpperBound;
}
u.subtreeUpperBound = cursor.valid() ? &cursor.get() : update->subtreeUpperBound;
u.cEnd = cursor;
u.skipLen = 0; // TODO: set this
// Find the mutation buffer range that includes all changes to the range described by u
mEnd = mutationBuffer->lower_bound(u.subtreeUpperBound->key);
// If the mutation range described by mBegin extends to mEnd, then see if the part of that range
// that overlaps with u's subtree range is being fully cleared or fully unchanged.
auto next = mBegin;
++next;
if (next == mEnd) {
// Check for uniform clearedness or unchangedness for the range mutation where it overlaps u's
// subtree
const KeyRef& mutationBoundaryKey = mBegin.key();
const RangeMutation& range = mBegin.mutation();
bool uniform;
if (range.clearAfterBoundary) {
// If the mutation range after the boundary key is cleared, then the mutation boundary key must
// be cleared or must be different than the subtree lower bound key so that it doesn't matter
uniform = range.boundaryCleared() || mutationBoundaryKey != u.subtreeLowerBound->key;
} else {
// If the mutation range after the boundary key is unchanged, then the mutation boundary key
// must be also unchanged or must be different than the subtree lower bound key so that it
// doesn't matter
uniform = !range.boundaryChanged || mutationBoundaryKey != u.subtreeLowerBound->key;
}
// If u's subtree is either all cleared or all unchanged
if (uniform) {
// We do not need to recurse to this subtree. Next, let's see if we can embiggen u's range to
// include sibling subtrees also covered by (mBegin, mEnd) so we can not recurse to those, too.
// If the cursor is valid, u.subtreeUpperBound is the cursor's position, which is >= mEnd.key().
// If equal, no range expansion is possible.
if (cursor.valid() && mEnd.key() != u.subtreeUpperBound->key) {
cursor.seekLessThanOrEqual(mEnd.key(), update->skipLen, &cursor, 1);
// If this seek moved us ahead, to something other than cEnd, then update subtree range
// boundaries
if (cursor != u.cEnd) {
// If the cursor is at a record with a null child, back up one step because it is in the
// middle of the next logical subtree, as null child records are not subtree boundaries.
ASSERT(cursor.valid());
if (!cursor.get().value.present()) {
cursor.movePrev();
}
u.cEnd = cursor;
u.subtreeUpperBound = &cursor.get();
u.skipLen = 0; // TODO: set this
// The new decode upper bound is either cEnd or the record before it if it has no child
// link
auto c = u.cEnd;
c.movePrev();
ASSERT(c.valid());
if (!c.get().value.present()) {
u.decodeUpperBound = &c.get();
u.expectedUpperBound = nullptr;
} else {
u.decodeUpperBound = u.subtreeUpperBound;
u.expectedUpperBound = u.subtreeUpperBound;
}
}
}
// The subtree range is either fully cleared or unchanged.
if (range.clearAfterBoundary) {
// Cleared
u.cleared();
auto c = u.cBegin;
while (c != u.cEnd) {
const RedwoodRecordRef& rec = c.get();
if (rec.value.present()) {
if (btPage->height == 2) {
debug_printf("%s: freeing child page in cleared subtree range: %s\n",
context.c_str(),
::toString(rec.getChildPage()).c_str());
self->freeBTreePage(rec.getChildPage(), writeVersion);
} else {
debug_printf("%s: queuing subtree deletion cleared subtree range: %s\n",
context.c_str(),
::toString(rec.getChildPage()).c_str());
self->m_lazyClearQueue.pushFront(
LazyClearQueueEntry{ writeVersion, rec.getChildPage() });
}
}
c.moveNext();
}
} else {
// Subtree range unchanged
}
debug_printf("%s: MutationBuffer covers this range in a single mutation, not recursing: %s\n",
context.c_str(),
u.toString().c_str());
// u has already been initialized with the correct result, no recursion needed, so restart the
// loop.
continue;
}
}
// If this page has height of 2 then its children are leaf nodes
recursions.push_back(
self->commitSubtree(self, snapshot, mutationBuffer, pageID, btPage->height == 2, mBegin, mEnd, &u));
}
debug_printf(
"%s Recursions from internal page started. pageSize=%d level=%d children=%d slices=%d recursions=%d\n",
context.c_str(),
btPage->size(),
btPage->height,
btPage->tree().numItems,
slices.size(),
recursions.size());
wait(waitForAll(recursions));
debug_printf("%s Recursions done, processing slice updates.\n", context.c_str());
// Note: parentInfo could be invalid after a wait and must be re-initialized.
// All uses below occur before waits so no reinitialization is done.
state ParentInfo* parentInfo = &self->childUpdateTracker[rootID.front()];
state InternalPageModifier m(btPage, cursor.mirror, tryToUpdate, parentInfo);
// Apply the possible changes for each subtree range recursed to, except the last one.
// For each range, the expected next record, if any, is checked against the first boundary
// of the next range, if any.
for (int i = 0, iEnd = slices.size() - 1; i < iEnd; ++i) {
m.applyUpdate(*slices[i], slices[i + 1]->getFirstBoundary());
}
// The expected next record for the final range is checked against one of the upper boundaries passed to
// this commitSubtree() instance. If changes have already been made, then the subtree upper boundary is
// passed, so in the event a different upper boundary is needed it will be added to the already-modified
// page. Otherwise, the decode boundary is used which will prevent this page from being modified for the
// sole purpose of adding a dummy upper bound record.
debug_printf("%s Applying final child range update. changesMade=%d Parent update is: %s\n",
context.c_str(),
m.changesMade,
update->toString().c_str());
m.applyUpdate(*slices.back(), m.changesMade ? update->subtreeUpperBound : update->decodeUpperBound);
state bool detachChildren = (parentInfo->count > 2);
state bool forceUpdate = false;
// If no changes were made, but we should rewrite it to point directly to remapped child pages
if (!m.changesMade && detachChildren) {
debug_printf(
"%s Internal page forced rewrite because at least %d children have been updated in-place.\n",
context.c_str(),
parentInfo->count);
forceUpdate = true;
if (!m.updating) {
m.updating = true;
// Copy the page before modification if the page references the cache
if (fromCache) {
page = self->cloneForUpdate(page);
cursor = getCursor(page);
btPage = (BTreePage*)page->begin();
m.btPage = btPage;
m.m = cursor.mirror;
fromCache = false;
}
}
++g_redwoodMetrics.level(btPage->height).forceUpdate;
}
// If page contents have changed
if (m.changesMade || forceUpdate) {
if (m.empty()) {
update->cleared();
debug_printf("%s All internal page children were deleted so deleting this page too, returning %s\n",
context.c_str(),
toString(*update).c_str());
self->freeBTreePage(rootID, writeVersion);
self->childUpdateTracker.erase(rootID.front());
} else {
if (m.updating) {
// Page was updated in place (or being forced to be updated in place to update child page ids)
debug_printf(
"%s Internal page modified in-place tryToUpdate=%d forceUpdate=%d detachChildren=%d\n",
context.c_str(),
tryToUpdate,
forceUpdate,
detachChildren);
if (detachChildren) {
int detached = 0;
cursor.moveFirst();
auto& stats = g_redwoodMetrics.level(btPage->height);
while (cursor.valid()) {
if (cursor.get().value.present()) {
for (auto& p : cursor.get().getChildPage()) {
if (parentInfo->maybeUpdated(p)) {
LogicalPageID newID = self->m_pager->detachRemappedPage(p, writeVersion);
if (newID != invalidLogicalPageID) {
debug_printf("%s Detach updated %u -> %u\n", context.c_str(), p, newID);
p = newID;
++stats.detachChild;
++detached;
}
}
}
}
cursor.moveNext();
}
parentInfo->clear();
if (forceUpdate && detached == 0) {
debug_printf("%s No children detached during forced update, returning %s\n",
context.c_str(),
toString(*update).c_str());
return Void();
}
}
BTreePageIDRef newID = wait(self->updateBTreePage(
self, rootID, &update->newLinks.arena(), page.castTo<ArenaPage>(), writeVersion));
debug_printf(
"%s commitSubtree(): Internal page updated in-place at version %s, new contents: %s\n",
context.c_str(),
toString(writeVersion).c_str(),
btPage
->toString(false,
newID,
snapshot->getVersion(),
update->decodeLowerBound,
update->decodeUpperBound)
.c_str());
update->updatedInPlace(newID, btPage, newID.size() * self->m_blockSize);
debug_printf("%s Internal page updated in-place, returning %s\n",
context.c_str(),
toString(*update).c_str());
} else {
// Page was rebuilt, possibly split.
debug_printf("%s Internal page could not be modified, rebuilding replacement(s).\n",
context.c_str());
if (detachChildren) {
auto& stats = g_redwoodMetrics.level(btPage->height);
for (auto& rec : m.rebuild) {
if (rec.value.present()) {
BTreePageIDRef oldPages = rec.getChildPage();
BTreePageIDRef newPages;
for (int i = 0; i < oldPages.size(); ++i) {
LogicalPageID p = oldPages[i];
if (parentInfo->maybeUpdated(p)) {
LogicalPageID newID = self->m_pager->detachRemappedPage(p, writeVersion);
if (newID != invalidLogicalPageID) {
// Rebuild record values reference original page memory so make a copy
if (newPages.empty()) {
newPages = BTreePageIDRef(m.rebuild.arena(), oldPages);
rec.setChildPage(newPages);
}
debug_printf("%s Detach updated %u -> %u\n", context.c_str(), p, newID);
newPages[i] = newID;
++stats.detachChild;
}
}
}
}
}
parentInfo->clear();
}
Standalone<VectorRef<RedwoodRecordRef>> newChildEntries =
wait(writePages(self,
update->subtreeLowerBound,
update->subtreeUpperBound,
m.rebuild,
btPage->height,
writeVersion,
rootID));
update->rebuilt(newChildEntries);
debug_printf(
"%s Internal page rebuilt, returning %s\n", context.c_str(), toString(*update).c_str());
}
}
} else {
debug_printf("%s Page has no changes, returning %s\n", context.c_str(), toString(*update).c_str());
}
return Void();
}
}
ACTOR static Future<Void> commit_impl(VersionedBTree* self) {
state MutationBuffer* mutations = self->m_pBuffer;
// No more mutations are allowed to be written to this mutation buffer we will commit
// at m_writeVersion, which we must save locally because it could change during commit.
self->m_pBuffer = nullptr;
state Version writeVersion = self->m_writeVersion;
// The latest mutation buffer start version is the one we will now (or eventually) commit.
state Version mutationBufferStartVersion = self->m_mutationBuffers.rbegin()->first;
// Replace the lastCommit future with a new one and then wait on the old one
state Promise<Void> committed;
Future<Void> previousCommit = self->m_latestCommit;
self->m_latestCommit = committed.getFuture();
// Wait for the latest commit to be finished.
wait(previousCommit);
self->m_pager->setOldestVersion(self->m_newOldestVersion);
debug_printf("%s: Beginning commit of version %" PRId64 ", new oldest version set to %" PRId64 "\n",
self->m_name.c_str(),
writeVersion,
self->m_newOldestVersion);
// Get the latest version from the pager, which is what we will read at
state Version latestVersion = self->m_pager->getLatestVersion();
debug_printf("%s: pager latestVersion %" PRId64 "\n", self->m_name.c_str(), latestVersion);
state Standalone<BTreePageIDRef> rootPageID = self->m_header.root.get();
state InternalPageSliceUpdate all;
state RedwoodRecordRef rootLink = dbBegin.withPageID(rootPageID);
all.subtreeLowerBound = &rootLink;
all.decodeLowerBound = &rootLink;
all.subtreeUpperBound = &dbEnd;
all.decodeUpperBound = &dbEnd;
all.skipLen = 0;
MutationBuffer::const_iterator mBegin = mutations->upper_bound(all.subtreeLowerBound->key);
--mBegin;
MutationBuffer::const_iterator mEnd = mutations->lower_bound(all.subtreeUpperBound->key);
wait(commitSubtree(self,
self->m_pager->getReadSnapshot(latestVersion),
mutations,
rootPageID,
self->m_header.height == 1,
mBegin,
mEnd,
&all));
// If the old root was deleted, write a new empty tree root node and free the old roots
if (all.childrenChanged) {
if (all.newLinks.empty()) {
debug_printf("Writing new empty root.\n");
LogicalPageID newRootID = wait(self->m_pager->newPageID());
Reference<ArenaPage> page = self->m_pager->newPageBuffer();
makeEmptyRoot(page);
self->m_header.height = 1;
self->m_pager->updatePage(newRootID, page);
rootPageID = BTreePageIDRef((LogicalPageID*)&newRootID, 1);
} else {
Standalone<VectorRef<RedwoodRecordRef>> newRootLevel(all.newLinks, all.newLinks.arena());
if (newRootLevel.size() == 1) {
rootPageID = newRootLevel.front().getChildPage();
} else {
// If the new root level's size is not 1 then build new root level(s)
Standalone<VectorRef<RedwoodRecordRef>> newRootPage =
wait(buildNewRoot(self, latestVersion, newRootLevel, self->m_header.height));
rootPageID = newRootPage.front().getChildPage();
}
}
}
self->m_header.root.set(rootPageID, sizeof(headerSpace) - sizeof(m_header));
self->m_lazyClearStop = true;
wait(success(self->m_lazyClearActor));
debug_printf("Lazy delete freed %u pages\n", self->m_lazyClearActor.get());
self->m_pager->setCommitVersion(writeVersion);
wait(self->m_lazyClearQueue.flush());
self->m_header.lazyDeleteQueue = self->m_lazyClearQueue.getState();
debug_printf("Setting metakey\n");
self->m_pager->setMetaKey(self->m_header.asKeyRef());
debug_printf("%s: Committing pager %" PRId64 "\n", self->m_name.c_str(), writeVersion);
wait(self->m_pager->commit());
debug_printf("%s: Committed version %" PRId64 "\n", self->m_name.c_str(), writeVersion);
// Now that everything is committed we must delete the mutation buffer.
// Our buffer's start version should be the oldest mutation buffer version in the map.
ASSERT(mutationBufferStartVersion == self->m_mutationBuffers.begin()->first);
self->m_mutationBuffers.erase(self->m_mutationBuffers.begin());
self->m_lastCommittedVersion = writeVersion;
++g_redwoodMetrics.opCommit;
self->m_lazyClearActor = incrementalLazyClear(self);
committed.send(Void());
return Void();
}
public:
// InternalCursor is for seeking to and iterating over the leaf-level RedwoodRecordRef records in the tree.
// The records could represent multiple values for the same key at different versions, including a non-present value
// representing a clear. Currently, however, all records are at version 0 and no clears are present in the tree.
struct InternalCursor {
private:
// Each InternalCursor's position is represented by a reference counted PageCursor, which links
// to its parent PageCursor, up to a PageCursor representing a cursor on the root page.
// PageCursors can be shared by many InternalCursors, making InternalCursor copying low overhead
struct PageCursor : ReferenceCounted<PageCursor>, FastAllocated<PageCursor> {
Reference<PageCursor> parent;
BTreePageIDRef pageID; // Only needed for debugging purposes
Reference<const ArenaPage> page;
BTreePage::BinaryTree::Cursor cursor;
// id will normally reference memory owned by the parent, which is okay because a reference to the parent
// will be held in the cursor
PageCursor(BTreePageIDRef id, Reference<const ArenaPage> page, Reference<PageCursor> parent = {})
: pageID(id), page(page), parent(parent), cursor(getCursor(page)) {}
PageCursor(const PageCursor& toCopy)
: parent(toCopy.parent), pageID(toCopy.pageID), page(toCopy.page), cursor(toCopy.cursor) {}
// Convenience method for copying a PageCursor
Reference<PageCursor> copy() const { return makeReference<PageCursor>(*this); }
const BTreePage* btPage() const { return (const BTreePage*)page->begin(); }
bool isLeaf() const { return btPage()->isLeaf(); }
Future<Reference<PageCursor>> getChild(Reference<IPagerSnapshot> pager, int readAheadBytes = 0) {
ASSERT(!isLeaf());
BTreePage::BinaryTree::Cursor next = cursor;
next.moveNext();
const RedwoodRecordRef& rec = cursor.get();
BTreePageIDRef id = rec.getChildPage();
Future<Reference<const ArenaPage>> child = readPage(pager, id, &rec, &next.getOrUpperBound());
// Read ahead siblings at level 2
// TODO: Application of readAheadBytes is not taking into account the size of the current page or any
// of the adjacent pages it is preloading.
if (readAheadBytes > 0 && btPage()->height == 2 && next.valid()) {
do {
debug_printf("preloading %s %d bytes left\n",
::toString(next.get().getChildPage()).c_str(),
readAheadBytes);
// If any part of the page was already loaded then stop
if (next.get().value.present()) {
preLoadPage(pager.getPtr(), next.get().getChildPage());
readAheadBytes -= page->size();
}
} while (readAheadBytes > 0 && next.moveNext());
}
return map(child, [=](Reference<const ArenaPage> page) {
return makeReference<PageCursor>(id, page, Reference<PageCursor>::addRef(this));
});
}
std::string toString() const {
return format("%s, %s",
::toString(pageID).c_str(),
cursor.valid() ? cursor.get().toString(isLeaf()).c_str() : "<invalid>");
}
};
Standalone<BTreePageIDRef> rootPageID;
Reference<IPagerSnapshot> pager;
Reference<PageCursor> pageCursor;
public:
InternalCursor() {}
InternalCursor(Reference<IPagerSnapshot> pager, BTreePageIDRef root) : pager(pager), rootPageID(root) {}
std::string toString() const {
std::string r;
Reference<PageCursor> c = pageCursor;
int maxDepth = 0;
while (c) {
c = c->parent;
++maxDepth;
}
c = pageCursor;
int depth = maxDepth;
while (c) {
r = format("[%d/%d: %s] ", depth--, maxDepth, c->toString().c_str()) + r;
c = c->parent;
}
return r;
}
// Returns true if cursor position is a valid leaf page record
bool valid() const { return pageCursor && pageCursor->isLeaf() && pageCursor->cursor.valid(); }
// Returns true if cursor position is valid() and has a present record value
bool present() const { return valid() && pageCursor->cursor.get().value.present(); }
// Returns true if cursor position is present() and has an effective version <= v
bool presentAtVersion(Version v) { return present() && pageCursor->cursor.get().version <= v; }
// This is to enable an optimization for the case where all internal records are at the
// same version and there are no implicit clears
// *this MUST be valid()
bool presentAtExactVersion(Version v) const { return present() && pageCursor->cursor.get().version == v; }
// Returns true if cursor position is present() and has an effective version <= v
bool validAtVersion(Version v) { return valid() && pageCursor->cursor.get().version <= v; }
const RedwoodRecordRef& get() const { return pageCursor->cursor.get(); }
// Ensure that pageCursor is not shared with other cursors so we can modify it
void ensureUnshared() {
if (!pageCursor->isSoleOwner()) {
pageCursor = pageCursor->copy();
}
}
Future<Void> moveToRoot() {
// If pageCursor exists follow parent links to the root
if (pageCursor) {
while (pageCursor->parent) {
pageCursor = pageCursor->parent;
}
return Void();
}
// Otherwise read the root page
Future<Reference<const ArenaPage>> root = readPage(pager, rootPageID, &dbBegin, &dbEnd);
return map(root, [=](Reference<const ArenaPage> p) {
pageCursor = makeReference<PageCursor>(rootPageID, p);
return Void();
});
}
ACTOR Future<bool> seekLessThan_impl(InternalCursor* self, RedwoodRecordRef query, int prefetchBytes) {
Future<Void> f = self->moveToRoot();
// f will almost always be ready
if (!f.isReady()) {
wait(f);
}
self->ensureUnshared();
loop {
bool isLeaf = self->pageCursor->isLeaf();
bool success = self->pageCursor->cursor.seekLessThan(query);
// Skip backwards over internal page entries that do not link to child pages
if (!isLeaf) {
// While record has no value, move again
while (success && !self->pageCursor->cursor.get().value.present()) {
success = self->pageCursor->cursor.movePrev();
}
}
if (success) {
// If we found a record < query at a leaf page then return success
if (isLeaf) {
return true;
}
Reference<PageCursor> child = wait(self->pageCursor->getChild(self->pager, prefetchBytes));
self->pageCursor = child;
} else {
// No records < query on this page, so move to immediate previous record at leaf level
bool success = wait(self->move(false));
return success;
}
}
}
Future<bool> seekLessThan(RedwoodRecordRef query, int prefetchBytes) {
return seekLessThan_impl(this, query, prefetchBytes);
}
ACTOR Future<bool> move_impl(InternalCursor* self, bool forward) {
// Try to move pageCursor, if it fails to go parent, repeat until it works or root cursor can't be moved
while (1) {
self->ensureUnshared();
bool success = self->pageCursor->cursor.valid() &&
(forward ? self->pageCursor->cursor.moveNext() : self->pageCursor->cursor.movePrev());
// Skip over internal page entries that do not link to child pages
if (!self->pageCursor->isLeaf()) {
// While record has no value, move again
while (success && !self->pageCursor->cursor.get().value.present()) {
success = forward ? self->pageCursor->cursor.moveNext() : self->pageCursor->cursor.movePrev();
}
}
// Stop if successful or there's no parent to move to
if (success || !self->pageCursor->parent) {
break;
}
// Move to parent
self->pageCursor = self->pageCursor->parent;
}
// If pageCursor not valid we've reached an end of the tree
if (!self->pageCursor->cursor.valid()) {
return false;
}
// While not on a leaf page, move down to get to one.
while (!self->pageCursor->isLeaf()) {
// Skip over internal page entries that do not link to child pages
while (!self->pageCursor->cursor.get().value.present()) {
bool success = forward ? self->pageCursor->cursor.moveNext() : self->pageCursor->cursor.movePrev();
if (!success) {
return false;
}
}
Reference<PageCursor> child = wait(self->pageCursor->getChild(self->pager));
forward ? child->cursor.moveFirst() : child->cursor.moveLast();
self->pageCursor = child;
}
return true;
}
Future<bool> move(bool forward) { return move_impl(this, forward); }
// Move to the first or last record of the database.
ACTOR Future<bool> move_end(InternalCursor* self, bool begin) {
Future<Void> f = self->moveToRoot();
// f will almost always be ready
if (!f.isReady()) {
wait(f);
}
self->ensureUnshared();
loop {
// Move to first or last record in the page
bool success = begin ? self->pageCursor->cursor.moveFirst() : self->pageCursor->cursor.moveLast();
// Skip over internal page entries that do not link to child pages
if (!self->pageCursor->isLeaf()) {
// While record has no value, move past it
while (success && !self->pageCursor->cursor.get().value.present()) {
success = begin ? self->pageCursor->cursor.moveNext() : self->pageCursor->cursor.movePrev();
}
}
// If it worked, return true if we've reached a leaf page otherwise go to the next child
if (success) {
if (self->pageCursor->isLeaf()) {
return true;
}
Reference<PageCursor> child = wait(self->pageCursor->getChild(self->pager));
self->pageCursor = child;
} else {
return false;
}
}
}
Future<bool> moveFirst() { return move_end(this, true); }
Future<bool> moveLast() { return move_end(this, false); }
};
// Cursor designed for short lifespans.
// Holds references to all pages touched.
// All record references returned from it are valid until the cursor is destroyed.
class BTreeCursor {
public:
struct PathEntry {
Reference<const ArenaPage> page;
BTreePage::BinaryTree::Cursor cursor;
const BTreePage* btPage() const { return (BTreePage*)page->begin(); };
};
private:
VersionedBTree* btree;
Reference<IPagerSnapshot> pager;
bool valid;
std::vector<PathEntry> path;
public:
BTreeCursor() {}
bool isValid() const { return valid; }
std::string toString() const {
std::string r = format("{ptr=%p %s ", this, ::toString(pager->getVersion()).c_str());
for (int i = 0; i < path.size(); ++i) {
r += format("[%d/%d: %s] ",
i + 1,
path.size(),
path[i].cursor.valid() ? path[i].cursor.get().toString(path[i].btPage()->isLeaf()).c_str()
: "<invalid>");
}
if (!valid) {
r += " (invalid) ";
}
r += "}";
return r;
}
const RedwoodRecordRef& get() { return path.back().cursor.get(); }
bool inRoot() const { return path.size() == 1; }
// To enable more efficient range scans, caller can read the lowest page
// of the cursor and pop it.
PathEntry& back() { return path.back(); }
void popPath() { path.pop_back(); }
Future<Void> pushPage(BTreePageIDRef id,
const RedwoodRecordRef& lowerBound,
const RedwoodRecordRef& upperBound) {
return map(readPage(pager, id, &lowerBound, &upperBound), [this, id](Reference<const ArenaPage> p) {
path.push_back({ p, getCursor(p) });
return Void();
});
}
Future<Void> pushPage(BTreePage::BinaryTree::Cursor c) {
const RedwoodRecordRef& rec = c.get();
auto next = c;
next.moveNext();
BTreePageIDRef id = rec.getChildPage();
return pushPage(id, rec, next.getOrUpperBound());
}
Future<Void> init(VersionedBTree* btree_in, Reference<IPagerSnapshot> pager_in, BTreePageIDRef root) {
btree = btree_in;
pager = pager_in;
path.reserve(6);
valid = false;
return pushPage(root, dbBegin, dbEnd);
}
// Seeks cursor to query if it exists, the record before or after it, or an undefined and invalid
// position between those records
// If 0 is returned, then
// If the cursor is valid then it points to query
// If the cursor is not valid then the cursor points to some place in the btree such that
// If there is a record in the tree < query then movePrev() will move to it, and
// If there is a record in the tree > query then moveNext() will move to it.
// If non-zero is returned then the cursor is valid and the return value is logically equivalent
// to query.compare(cursor.get())
ACTOR Future<int> seek_impl(BTreeCursor* self, RedwoodRecordRef query, int prefetchBytes) {
state RedwoodRecordRef internalPageQuery = query.withMaxPageID();
self->path.resize(1);
debug_printf(
"seek(%s, %d) start cursor = %s\n", query.toString().c_str(), prefetchBytes, self->toString().c_str());
loop {
auto& entry = self->path.back();
if (entry.btPage()->isLeaf()) {
int cmp = entry.cursor.seek(query);
self->valid = entry.cursor.valid() && !entry.cursor.node->isDeleted();
debug_printf("seek(%s, %d) loop exit cmp=%d cursor=%s\n",
query.toString().c_str(),
prefetchBytes,
cmp,
self->toString().c_str());
return self->valid ? cmp : 0;
}
// Internal page, so seek to the branch where query must be
// Currently, after a subtree deletion internal page boundaries are still strictly adhered
// to and will be updated if anything is inserted into the cleared range, so if the seek fails
// or it finds an entry with a null child page then query does not exist in the BTree.
if (entry.cursor.seekLessThan(internalPageQuery) && entry.cursor.get().value.present()) {
debug_printf("seek(%s, %d) loop seek success cursor=%s\n",
query.toString().c_str(),
prefetchBytes,
self->toString().c_str());
Future<Void> f = self->pushPage(entry.cursor);
// Prefetch siblings, at least prefetchBytes, at level 2 but without jumping to another level 2
// sibling
if (prefetchBytes != 0 && entry.btPage()->height == 2) {
auto c = entry.cursor;
bool fwd = prefetchBytes > 0;
prefetchBytes = abs(prefetchBytes);
// While we should still preload more bytes and a move in the target direction is successful
while (prefetchBytes > 0 && (fwd ? c.moveNext() : c.movePrev())) {
// If there is a page link, preload it.
if (c.get().value.present()) {
BTreePageIDRef childPage = c.get().getChildPage();
preLoadPage(self->pager.getPtr(), childPage);
prefetchBytes -= self->btree->m_blockSize * childPage.size();
}
}
}
wait(f);
} else {
self->valid = false;
debug_printf("seek(%s, %d) loop exit cmp=0 cursor=%s\n",
query.toString().c_str(),
prefetchBytes,
self->toString().c_str());
return 0;
}
}
}
Future<int> seek(RedwoodRecordRef query, int prefetchBytes) { return seek_impl(this, query, prefetchBytes); }
ACTOR Future<Void> seekGTE_impl(BTreeCursor* self, RedwoodRecordRef query, int prefetchBytes) {
debug_printf("seekGTE(%s, %d) start\n", query.toString().c_str(), prefetchBytes);
int cmp = wait(self->seek(query, prefetchBytes));
if (cmp > 0 || (cmp == 0 && !self->isValid())) {
wait(self->moveNext());
}
return Void();
}
Future<Void> seekGTE(RedwoodRecordRef query, int prefetchBytes) {
return seekGTE_impl(this, query, prefetchBytes);
}
ACTOR Future<Void> seekLT_impl(BTreeCursor* self, RedwoodRecordRef query, int prefetchBytes) {
debug_printf("seekLT(%s, %d) start\n", query.toString().c_str(), prefetchBytes);
int cmp = wait(self->seek(query, prefetchBytes));
if (cmp <= 0) {
wait(self->movePrev());
}
return Void();
}
Future<Void> seekLT(RedwoodRecordRef query, int prefetchBytes) {
return seekLT_impl(this, query, -prefetchBytes);
}
ACTOR Future<Void> move_impl(BTreeCursor* self, bool forward) {
// Try to the move cursor at the end of the path in the correct direction
debug_printf("move%s() start cursor=%s\n", forward ? "Next" : "Prev", self->toString().c_str());
while (1) {
debug_printf("move%s() first loop cursor=%s\n", forward ? "Next" : "Prev", self->toString().c_str());
auto& entry = self->path.back();
bool success;
if (entry.cursor.valid()) {
success = forward ? entry.cursor.moveNext() : entry.cursor.movePrev();
} else {
success = forward ? entry.cursor.moveFirst() : false;
}
// Skip over internal page entries that do not link to child pages. There should never be two in a row.
if (success && !entry.btPage()->isLeaf() && !entry.cursor.get().value.present()) {
success = forward ? entry.cursor.moveNext() : entry.cursor.movePrev();
ASSERT(!success || entry.cursor.get().value.present());
}
// Stop if successful
if (success) {
break;
}
if (self->path.size() == 1) {
self->valid = false;
return Void();
}
// Move to parent
self->path.pop_back();
}
// While not on a leaf page, move down to get to one.
while (1) {
debug_printf("move%s() second loop cursor=%s\n", forward ? "Next" : "Prev", self->toString().c_str());
auto& entry = self->path.back();
if (entry.btPage()->isLeaf()) {
break;
}
// The last entry in an internal page could be a null link, if so move back
if (!forward && !entry.cursor.get().value.present()) {
ASSERT(entry.cursor.movePrev());
ASSERT(entry.cursor.get().value.present());
}
wait(self->pushPage(entry.cursor));
auto& newEntry = self->path.back();
ASSERT(forward ? newEntry.cursor.moveFirst() : newEntry.cursor.moveLast());
}
self->valid = true;
debug_printf("move%s() exit cursor=%s\n", forward ? "Next" : "Prev", self->toString().c_str());
return Void();
}
Future<Void> moveNext() { return move_impl(this, true); }
Future<Void> movePrev() { return move_impl(this, false); }
};
Future<Void> initBTreeCursor(BTreeCursor* cursor, Version snapshotVersion) {
// Only committed versions can be read.
ASSERT(snapshotVersion <= m_lastCommittedVersion);
Reference<IPagerSnapshot> snapshot = m_pager->getReadSnapshot(snapshotVersion);
// This is a ref because snapshot will continue to hold the metakey value memory
KeyRef m = snapshot->getMetaKey();
return cursor->init(this, snapshot, ((MetaKey*)m.begin())->root.get());
}
// Cursor is for reading and interating over user visible KV pairs at a specific version
// KeyValueRefs returned become invalid once the cursor is moved
class Cursor : public IStoreCursor, public ReferenceCounted<Cursor>, public FastAllocated<Cursor>, NonCopyable {
public:
Cursor(Reference<IPagerSnapshot> pageSource, BTreePageIDRef root, Version internalRecordVersion)
: m_version(internalRecordVersion), m_cur1(pageSource, root), m_cur2(m_cur1) {}
void addref() override { ReferenceCounted<Cursor>::addref(); }
void delref() override { ReferenceCounted<Cursor>::delref(); }
private:
Version m_version;
// If kv is valid
// - kv.key references memory held by cur1
// - If cur1 points to a non split KV pair
// - kv.value references memory held by cur1
// - cur2 points to the next internal record after cur1
// Else
// - kv.value references memory in arena
// - cur2 points to the first internal record of the split KV pair
InternalCursor m_cur1;
InternalCursor m_cur2;
Arena m_arena;
Optional<KeyValueRef> m_kv;
public:
Future<Void> findEqual(KeyRef key) override { return find_impl(this, key, 0); }
Future<Void> findFirstEqualOrGreater(KeyRef key, int prefetchBytes) override {
return find_impl(this, key, 1, prefetchBytes);
}
Future<Void> findLastLessOrEqual(KeyRef key, int prefetchBytes) override {
return find_impl(this, key, -1, prefetchBytes);
}
Future<Void> next() override { return move(this, true); }
Future<Void> prev() override { return move(this, false); }
bool isValid() override { return m_kv.present(); }
KeyRef getKey() override { return m_kv.get().key; }
ValueRef getValue() override { return m_kv.get().value; }
std::string toString(bool includePaths = true) const {
std::string r;
r += format("Cursor(%p) ver: %" PRId64 " ", this, m_version);
if (m_kv.present()) {
r += format(
" KV: '%s' -> '%s'", m_kv.get().key.printable().c_str(), m_kv.get().value.printable().c_str());
} else {
r += " KV: <np>";
}
if (includePaths) {
r += format("\n Cur1: %s", m_cur1.toString().c_str());
r += format("\n Cur2: %s", m_cur2.toString().c_str());
} else {
if (m_cur1.valid()) {
r += format("\n Cur1: %s", m_cur1.get().toString().c_str());
}
if (m_cur2.valid()) {
r += format("\n Cur2: %s", m_cur2.get().toString().c_str());
}
}
return r;
}
private:
// find key in tree closest to or equal to key (at this cursor's version)
// for less than or equal use cmp < 0
// for greater than or equal use cmp > 0
// for equal use cmp == 0
ACTOR static Future<Void> find_impl(Cursor* self, KeyRef key, int cmp, int prefetchBytes = 0) {
state RedwoodRecordRef query(key, self->m_version + 1);
self->m_kv.reset();
wait(success(self->m_cur1.seekLessThan(query, prefetchBytes)));
debug_printf("find%sE(%s): %s\n",
cmp > 0 ? "GT" : (cmp == 0 ? "" : "LT"),
query.toString().c_str(),
self->toString().c_str());
// If we found the target key with a present value then return it as it is valid for any cmp type
if (self->m_cur1.present() && self->m_cur1.get().key == key) {
debug_printf("Target key found. Cursor: %s\n", self->toString().c_str());
self->m_kv = self->m_cur1.get().toKeyValueRef();
return Void();
}
// If cmp type is Equal and we reached here, we didn't find it
if (cmp == 0) {
return Void();
}
// cmp mode is GreaterThanOrEqual, so if we've reached here an equal key was not found and cur1 either
// points to a lesser key or is invalid.
if (cmp > 0) {
// If cursor is invalid, query was less than the first key in database so go to the first record
if (!self->m_cur1.valid()) {
bool valid = wait(self->m_cur1.moveFirst());
if (!valid) {
self->m_kv.reset();
return Void();
}
} else {
// Otherwise, move forward until we find a key greater than the target key.
// If multiversion data is present, the next record could have the same key as the initial
// record found but be at a newer version.
loop {
bool valid = wait(self->m_cur1.move(true));
if (!valid) {
self->m_kv.reset();
return Void();
}
if (self->m_cur1.get().key > key) {
break;
}
}
}
// Get the next present key at the target version. Handles invalid cursor too.
wait(self->next());
} else if (cmp < 0) {
// cmp mode is LessThanOrEqual. An equal key to the target key was already checked above, and the
// search was for LessThan query, so cur1 is already in the right place.
if (!self->m_cur1.valid()) {
self->m_kv.reset();
return Void();
}
// Move to previous present kv pair at the target version
wait(self->prev());
}
return Void();
}
ACTOR static Future<Void> move(Cursor* self, bool fwd) {
debug_printf("Cursor::move(%d): Start %s\n", fwd, self->toString().c_str());
ASSERT(self->m_cur1.valid());
// If kv is present then the key/version at cur1 was already returned so move to a new key
// Move cur1 until failure or a new key is found, keeping prior record visited in cur2
if (self->m_kv.present()) {
ASSERT(self->m_cur1.valid());
loop {
self->m_cur2 = self->m_cur1;
debug_printf("Cursor::move(%d): Advancing cur1 %s\n", fwd, self->toString().c_str());
bool valid = wait(self->m_cur1.move(fwd));
if (!valid || self->m_cur1.get().key != self->m_cur2.get().key) {
break;
}
}
}
// Given two consecutive cursors c1 and c2, c1 represents a returnable record if
// c1 is present at exactly version v
// OR
// c1 is.presentAtVersion(v) && (!c2.validAtVersion() || c2.get().key != c1.get().key())
// Note the distinction between 'present' and 'valid'. Present means the value for the key
// exists at the version (but could be the empty string) while valid just means the internal
// record is in effect at that version but it could indicate that the key was cleared and
// no longer exists from the user's perspective at that version
if (self->m_cur1.valid()) {
self->m_cur2 = self->m_cur1;
debug_printf("Cursor::move(%d): Advancing cur2 %s\n", fwd, self->toString().c_str());
wait(success(self->m_cur2.move(true)));
}
while (self->m_cur1.valid()) {
if (self->m_cur1.get().version == self->m_version ||
(self->m_cur1.presentAtVersion(self->m_version) &&
(!self->m_cur2.validAtVersion(self->m_version) ||
self->m_cur2.get().key != self->m_cur1.get().key))) {
self->m_kv = self->m_cur1.get().toKeyValueRef();
return Void();
}
if (fwd) {
// Moving forward, move cur2 forward and keep cur1 pointing to the prior (predecessor) record
debug_printf("Cursor::move(%d): Moving forward %s\n", fwd, self->toString().c_str());
self->m_cur1 = self->m_cur2;
wait(success(self->m_cur2.move(true)));
} else {
// Moving backward, move cur1 backward and keep cur2 pointing to the prior (successor) record
debug_printf("Cursor::move(%d): Moving backward %s\n", fwd, self->toString().c_str());
self->m_cur2 = self->m_cur1;
wait(success(self->m_cur1.move(false)));
}
}
debug_printf("Cursor::move(%d): Exit, end of db reached. Cursor = %s\n", fwd, self->toString().c_str());
self->m_kv.reset();
return Void();
}
};
};
#include "fdbserver/art_impl.h"
RedwoodRecordRef VersionedBTree::dbBegin(LiteralStringRef(""));
RedwoodRecordRef VersionedBTree::dbEnd(LiteralStringRef("\xff\xff\xff\xff\xff"));
class KeyValueStoreRedwoodUnversioned : public IKeyValueStore {
public:
KeyValueStoreRedwoodUnversioned(std::string filePrefix, UID logID)
: m_filePrefix(filePrefix), m_concurrentReads(new FlowLock(SERVER_KNOBS->REDWOOD_KVSTORE_CONCURRENT_READS)) {
// TODO: This constructor should really just take an IVersionedStore
int pageSize =
BUGGIFY ? deterministicRandom()->randomInt(1000, 4096 * 4) : SERVER_KNOBS->REDWOOD_DEFAULT_PAGE_SIZE;
int64_t pageCacheBytes =
g_network->isSimulated()
? (BUGGIFY ? deterministicRandom()->randomInt(pageSize, FLOW_KNOBS->BUGGIFY_SIM_PAGE_CACHE_4K)
: FLOW_KNOBS->SIM_PAGE_CACHE_4K)
: FLOW_KNOBS->PAGE_CACHE_4K;
Version remapCleanupWindow =
BUGGIFY ? deterministicRandom()->randomInt64(0, 1000) : SERVER_KNOBS->REDWOOD_REMAP_CLEANUP_WINDOW;
IPager2* pager = new DWALPager(pageSize, filePrefix, pageCacheBytes, remapCleanupWindow);
m_tree = new VersionedBTree(pager, filePrefix);
m_init = catchError(init_impl(this));
}
Future<Void> init() override { return m_init; }
ACTOR Future<Void> init_impl(KeyValueStoreRedwoodUnversioned* self) {
TraceEvent(SevInfo, "RedwoodInit").detail("FilePrefix", self->m_filePrefix);
wait(self->m_tree->init());
Version v = self->m_tree->getLatestVersion();
self->m_tree->setWriteVersion(v + 1);
TraceEvent(SevInfo, "RedwoodInitComplete").detail("FilePrefix", self->m_filePrefix);
return Void();
}
ACTOR void shutdown(KeyValueStoreRedwoodUnversioned* self, bool dispose) {
TraceEvent(SevInfo, "RedwoodShutdown").detail("FilePrefix", self->m_filePrefix).detail("Dispose", dispose);
if (self->m_error.canBeSet()) {
self->m_error.sendError(actor_cancelled()); // Ideally this should be shutdown_in_progress
}
self->m_init.cancel();
Future<Void> closedFuture = self->m_tree->onClosed();
if (dispose)
self->m_tree->dispose();
else
self->m_tree->close();
wait(closedFuture);
self->m_closed.send(Void());
TraceEvent(SevInfo, "RedwoodShutdownComplete")
.detail("FilePrefix", self->m_filePrefix)
.detail("Dispose", dispose);
delete self;
}
void close() override { shutdown(this, false); }
void dispose() override { shutdown(this, true); }
Future<Void> onClosed() override { return m_closed.getFuture(); }
Future<Void> commit(bool sequential = false) override {
Future<Void> c = m_tree->commit();
m_tree->setOldestVersion(m_tree->getLatestVersion());
m_tree->setWriteVersion(m_tree->getWriteVersion() + 1);
return catchError(c);
}
KeyValueStoreType getType() const override { return KeyValueStoreType::SSD_REDWOOD_V1; }
StorageBytes getStorageBytes() const override { return m_tree->getStorageBytes(); }
Future<Void> getError() override { return delayed(m_error.getFuture()); };
void clear(KeyRangeRef range, const Arena* arena = 0) override {
debug_printf("CLEAR %s\n", printable(range).c_str());
m_tree->clear(range);
}
void set(KeyValueRef keyValue, const Arena* arena = nullptr) override {
debug_printf("SET %s\n", printable(keyValue).c_str());
m_tree->set(keyValue);
}
Future<RangeResult> readRange(KeyRangeRef keys, int rowLimit = 1 << 30, int byteLimit = 1 << 30) override {
debug_printf("READRANGE %s\n", printable(keys).c_str());
return catchError(readRange_impl(this, keys, rowLimit, byteLimit));
}
ACTOR static Future<RangeResult> readRange_impl(KeyValueStoreRedwoodUnversioned* self,
KeyRange keys,
int rowLimit,
int byteLimit) {
state VersionedBTree::BTreeCursor cur;
wait(self->m_tree->initBTreeCursor(&cur, self->m_tree->getLastCommittedVersion()));
state Reference<FlowLock> readLock = self->m_concurrentReads;
wait(readLock->take());
state FlowLock::Releaser releaser(*readLock);
++g_redwoodMetrics.opGetRange;
state RangeResult result;
state int accumulatedBytes = 0;
ASSERT(byteLimit > 0);
if (rowLimit == 0) {
return result;
}
// Prefetch is disabled for now pending some decent logic for deciding how much to fetch
state int prefetchBytes = 0;
if (rowLimit > 0) {
wait(cur.seekGTE(keys.begin, prefetchBytes));
while (cur.isValid()) {
// Read page contents without using waits
BTreePage::BinaryTree::Cursor leafCursor = cur.back().cursor;
// we can bypass the bounds check for each key in the leaf if the entire leaf is in range
// > because both query end and page upper bound are exclusive of the query results and page contents,
// respectively
bool boundsCheck = leafCursor.upperBound() > keys.end;
// Whether or not any results from this page were added to results
bool usedPage = false;
while (leafCursor.valid()) {
KeyValueRef kv = leafCursor.get().toKeyValueRef();
if (boundsCheck && kv.key.compare(keys.end) >= 0) {
break;
}
accumulatedBytes += kv.expectedSize();
result.push_back(result.arena(), kv);
usedPage = true;
if (--rowLimit == 0 || accumulatedBytes >= byteLimit) {
break;
}
leafCursor.moveNext();
}
// If the page was used, results must depend on the ArenaPage arena and the Mirror arena.
// This must be done after visiting all the results in case the Mirror arena changes.
if (usedPage) {
result.arena().dependsOn(leafCursor.mirror->arena);
result.arena().dependsOn(cur.back().page->getArena());
}
// Stop if the leaf cursor is still valid which means we hit a key or size limit or
// if the cursor is in the root page, in which case there are no more pages.
if (leafCursor.valid() || cur.inRoot()) {
break;
}
cur.popPath();
wait(cur.moveNext());
}
} else {
wait(cur.seekLT(keys.end, prefetchBytes));
while (cur.isValid()) {
// Read page contents without using waits
BTreePage::BinaryTree::Cursor leafCursor = cur.back().cursor;
// we can bypass the bounds check for each key in the leaf if the entire leaf is in range
// < because both query begin and page lower bound are inclusive of the query results and page contents,
// respectively
bool boundsCheck = leafCursor.lowerBound() < keys.begin;
// Whether or not any results from this page were added to results
bool usedPage = false;
while (leafCursor.valid()) {
KeyValueRef kv = leafCursor.get().toKeyValueRef();
if (boundsCheck && kv.key.compare(keys.begin) < 0) {
break;
}
accumulatedBytes += kv.expectedSize();
result.push_back(result.arena(), kv);
usedPage = true;
if (++rowLimit == 0 || accumulatedBytes >= byteLimit) {
break;
}
leafCursor.movePrev();
}
// If the page was used, results must depend on the ArenaPage arena and the Mirror arena.
// This must be done after visiting all the results in case the Mirror arena changes.
if (usedPage) {
result.arena().dependsOn(leafCursor.mirror->arena);
result.arena().dependsOn(cur.back().page->getArena());
}
// Stop if the leaf cursor is still valid which means we hit a key or size limit or
// if we started in the root page
if (leafCursor.valid() || cur.inRoot()) {
break;
}
cur.popPath();
wait(cur.movePrev());
}
}
result.more = rowLimit == 0 || accumulatedBytes >= byteLimit;
if (result.more) {
ASSERT(result.size() > 0);
result.readThrough = result[result.size() - 1].key;
}
return result;
}
ACTOR static Future<Optional<Value>> readValue_impl(KeyValueStoreRedwoodUnversioned* self,
Key key,
Optional<UID> debugID) {
state VersionedBTree::BTreeCursor cur;
wait(self->m_tree->initBTreeCursor(&cur, self->m_tree->getLastCommittedVersion()));
state Reference<FlowLock> readLock = self->m_concurrentReads;
wait(readLock->take());
state FlowLock::Releaser releaser(*readLock);
++g_redwoodMetrics.opGet;
wait(cur.seekGTE(key, 0));
if (cur.isValid() && cur.get().key == key) {
// Return a Value whose arena depends on the source page arena
Value v;
v.arena().dependsOn(cur.back().page->getArena());
v.contents() = cur.get().value.get();
return v;
}
return Optional<Value>();
}
Future<Optional<Value>> readValue(KeyRef key, Optional<UID> debugID = Optional<UID>()) override {
return catchError(readValue_impl(this, key, debugID));
}
Future<Optional<Value>> readValuePrefix(KeyRef key,
int maxLength,
Optional<UID> debugID = Optional<UID>()) override {
return catchError(map(readValue_impl(this, key, debugID), [maxLength](Optional<Value> v) {
if (v.present() && v.get().size() > maxLength) {
v.get().contents() = v.get().substr(0, maxLength);
}
return v;
}));
}
~KeyValueStoreRedwoodUnversioned() override{};
private:
std::string m_filePrefix;
VersionedBTree* m_tree;
Future<Void> m_init;
Promise<Void> m_closed;
Promise<Void> m_error;
Reference<FlowLock> m_concurrentReads;
template <typename T>
inline Future<T> catchError(Future<T> f) {
return forwardError(f, m_error);
}
};
IKeyValueStore* keyValueStoreRedwoodV1(std::string const& filename, UID logID) {
return new KeyValueStoreRedwoodUnversioned(filename, logID);
}
int randomSize(int max) {
int n = pow(deterministicRandom()->random01(), 3) * max;
return n;
}
StringRef randomString(Arena& arena, int len, char firstChar = 'a', char lastChar = 'z') {
++lastChar;
StringRef s = makeString(len, arena);
for (int i = 0; i < len; ++i) {
*(uint8_t*)(s.begin() + i) = (uint8_t)deterministicRandom()->randomInt(firstChar, lastChar);
}
return s;
}
Standalone<StringRef> randomString(int len, char firstChar = 'a', char lastChar = 'z') {
Standalone<StringRef> s;
(StringRef&)s = randomString(s.arena(), len, firstChar, lastChar);
return s;
}
KeyValue randomKV(int maxKeySize = 10, int maxValueSize = 5) {
int kLen = randomSize(1 + maxKeySize);
int vLen = maxValueSize > 0 ? randomSize(maxValueSize) : 0;
KeyValue kv;
kv.key = randomString(kv.arena(), kLen, 'a', 'm');
for (int i = 0; i < kLen; ++i)
mutateString(kv.key)[i] = (uint8_t)deterministicRandom()->randomInt('a', 'm');
if (vLen > 0) {
kv.value = randomString(kv.arena(), vLen, 'n', 'z');
for (int i = 0; i < vLen; ++i)
mutateString(kv.value)[i] = (uint8_t)deterministicRandom()->randomInt('o', 'z');
}
return kv;
}
// Verify a range using a BTreeCursor.
// Assumes that the BTree holds a single data version and the version is 0.
ACTOR Future<int> verifyRangeBTreeCursor(VersionedBTree* btree,
Key start,
Key end,
Version v,
std::map<std::pair<std::string, Version>, Optional<std::string>>* written,
int* pErrorCount) {
state int errors = 0;
if (end <= start)
end = keyAfter(start);
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator i =
written->lower_bound(std::make_pair(start.toString(), 0));
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator iEnd =
written->upper_bound(std::make_pair(end.toString(), 0));
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator iLast;
state VersionedBTree::BTreeCursor cur;
wait(btree->initBTreeCursor(&cur, v));
debug_printf("VerifyRange(@%" PRId64 ", %s, %s): Start\n", v, start.printable().c_str(), end.printable().c_str());
// Randomly use the cursor for something else first.
if (deterministicRandom()->coinflip()) {
state Key randomKey = randomKV().key;
debug_printf("VerifyRange(@%" PRId64 ", %s, %s): Dummy seek to '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
randomKey.toString().c_str());
wait(success(cur.seek(randomKey, 0)));
}
debug_printf(
"VerifyRange(@%" PRId64 ", %s, %s): Actual seek\n", v, start.printable().c_str(), end.printable().c_str());
wait(cur.seekGTE(start, 0));
state Standalone<VectorRef<KeyValueRef>> results;
while (cur.isValid() && cur.get().key < end) {
// Find the next written kv pair that would be present at this version
while (1) {
iLast = i;
if (i == iEnd)
break;
++i;
if (iLast->first.second <= v && iLast->second.present() &&
(i == iEnd || i->first.first != iLast->first.first || i->first.second > v)) {
debug_printf("VerifyRange(@%" PRId64 ", %s, %s) Found key in written map: %s\n",
v,
start.printable().c_str(),
end.printable().c_str(),
iLast->first.first.c_str());
break;
}
}
if (iLast == iEnd) {
++errors;
++*pErrorCount;
printf("VerifyRange(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' vs nothing in written map.\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur.get().key.toString().c_str());
break;
}
if (cur.get().key != iLast->first.first) {
++errors;
++*pErrorCount;
printf("VerifyRange(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' but expected '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur.get().key.toString().c_str(),
iLast->first.first.c_str());
break;
}
if (cur.get().value.get() != iLast->second.get()) {
++errors;
++*pErrorCount;
printf("VerifyRange(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' has tree value '%s' but expected '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur.get().key.toString().c_str(),
cur.get().value.get().toString().c_str(),
iLast->second.get().c_str());
break;
}
ASSERT(errors == 0);
results.push_back(results.arena(), cur.get().toKeyValueRef());
results.arena().dependsOn(cur.back().cursor.mirror->arena);
results.arena().dependsOn(cur.back().page->getArena());
wait(cur.moveNext());
}
// Make sure there are no further written kv pairs that would be present at this version.
while (1) {
iLast = i;
if (i == iEnd)
break;
++i;
if (iLast->first.second <= v && iLast->second.present() &&
(i == iEnd || i->first.first != iLast->first.first || i->first.second > v))
break;
}
if (iLast != iEnd) {
++errors;
++*pErrorCount;
printf("VerifyRange(@%" PRId64 ", %s, %s) ERROR: Tree range ended but written has @%" PRId64 " '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
iLast->first.second,
iLast->first.first.c_str());
}
debug_printf(
"VerifyRangeReverse(@%" PRId64 ", %s, %s): start\n", v, start.printable().c_str(), end.printable().c_str());
// Randomly use a new cursor at the same version for the reverse range read, if the version is still available for
// opening new cursors
if (v >= btree->getOldestVersion() && deterministicRandom()->coinflip()) {
cur = VersionedBTree::BTreeCursor();
wait(btree->initBTreeCursor(&cur, v));
}
// Now read the range from the tree in reverse order and compare to the saved results
wait(cur.seekLT(end, 0));
state std::reverse_iterator<const KeyValueRef*> r = results.rbegin();
while (cur.isValid() && cur.get().key >= start) {
if (r == results.rend()) {
++errors;
++*pErrorCount;
printf("VerifyRangeReverse(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' vs nothing in written map.\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur.get().key.toString().c_str());
break;
}
if (cur.get().key != r->key) {
++errors;
++*pErrorCount;
printf("VerifyRangeReverse(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' but expected '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur.get().key.toString().c_str(),
r->key.toString().c_str());
break;
}
if (cur.get().value.get() != r->value) {
++errors;
++*pErrorCount;
printf("VerifyRangeReverse(@%" PRId64
", %s, %s) ERROR: Tree key '%s' has tree value '%s' but expected '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur.get().key.toString().c_str(),
cur.get().value.get().toString().c_str(),
r->value.toString().c_str());
break;
}
++r;
wait(cur.movePrev());
}
if (r != results.rend()) {
++errors;
++*pErrorCount;
printf("VerifyRangeReverse(@%" PRId64 ", %s, %s) ERROR: Tree range ended but written has '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
r->key.toString().c_str());
}
return errors;
}
ACTOR Future<int> verifyRange(VersionedBTree* btree,
Key start,
Key end,
Version v,
std::map<std::pair<std::string, Version>, Optional<std::string>>* written,
int* pErrorCount) {
state int errors = 0;
if (end <= start)
end = keyAfter(start);
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator i =
written->lower_bound(std::make_pair(start.toString(), 0));
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator iEnd =
written->upper_bound(std::make_pair(end.toString(), 0));
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator iLast;
state Reference<IStoreCursor> cur = btree->readAtVersion(v);
debug_printf("VerifyRange(@%" PRId64 ", %s, %s): Start cur=%p\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur.getPtr());
// Randomly use the cursor for something else first.
if (deterministicRandom()->coinflip()) {
state Key randomKey = randomKV().key;
debug_printf("VerifyRange(@%" PRId64 ", %s, %s): Dummy seek to '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
randomKey.toString().c_str());
wait(deterministicRandom()->coinflip() ? cur->findFirstEqualOrGreater(randomKey)
: cur->findLastLessOrEqual(randomKey));
}
debug_printf(
"VerifyRange(@%" PRId64 ", %s, %s): Actual seek\n", v, start.printable().c_str(), end.printable().c_str());
wait(cur->findFirstEqualOrGreater(start));
state std::vector<KeyValue> results;
while (cur->isValid() && cur->getKey() < end) {
// Find the next written kv pair that would be present at this version
while (1) {
iLast = i;
if (i == iEnd)
break;
++i;
if (iLast->first.second <= v && iLast->second.present() &&
(i == iEnd || i->first.first != iLast->first.first || i->first.second > v)) {
debug_printf("VerifyRange(@%" PRId64 ", %s, %s) Found key in written map: %s\n",
v,
start.printable().c_str(),
end.printable().c_str(),
iLast->first.first.c_str());
break;
}
}
if (iLast == iEnd) {
++errors;
++*pErrorCount;
printf("VerifyRange(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' vs nothing in written map.\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur->getKey().toString().c_str());
break;
}
if (cur->getKey() != iLast->first.first) {
++errors;
++*pErrorCount;
printf("VerifyRange(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' but expected '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur->getKey().toString().c_str(),
iLast->first.first.c_str());
break;
}
if (cur->getValue() != iLast->second.get()) {
++errors;
++*pErrorCount;
printf("VerifyRange(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' has tree value '%s' but expected '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur->getKey().toString().c_str(),
cur->getValue().toString().c_str(),
iLast->second.get().c_str());
break;
}
ASSERT(errors == 0);
results.push_back(KeyValue(KeyValueRef(cur->getKey(), cur->getValue())));
wait(cur->next());
}
// Make sure there are no further written kv pairs that would be present at this version.
while (1) {
iLast = i;
if (i == iEnd)
break;
++i;
if (iLast->first.second <= v && iLast->second.present() &&
(i == iEnd || i->first.first != iLast->first.first || i->first.second > v))
break;
}
if (iLast != iEnd) {
++errors;
++*pErrorCount;
printf("VerifyRange(@%" PRId64 ", %s, %s) ERROR: Tree range ended but written has @%" PRId64 " '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
iLast->first.second,
iLast->first.first.c_str());
}
debug_printf(
"VerifyRangeReverse(@%" PRId64 ", %s, %s): start\n", v, start.printable().c_str(), end.printable().c_str());
// Randomly use a new cursor at the same version for the reverse range read, if the version is still available for
// opening new cursors
if (v >= btree->getOldestVersion() && deterministicRandom()->coinflip()) {
cur = btree->readAtVersion(v);
}
// Now read the range from the tree in reverse order and compare to the saved results
wait(cur->findLastLessOrEqual(end));
if (cur->isValid() && cur->getKey() == end)
wait(cur->prev());
state std::vector<KeyValue>::const_reverse_iterator r = results.rbegin();
while (cur->isValid() && cur->getKey() >= start) {
if (r == results.rend()) {
++errors;
++*pErrorCount;
printf("VerifyRangeReverse(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' vs nothing in written map.\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur->getKey().toString().c_str());
break;
}
if (cur->getKey() != r->key) {
++errors;
++*pErrorCount;
printf("VerifyRangeReverse(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' but expected '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur->getKey().toString().c_str(),
r->key.toString().c_str());
break;
}
if (cur->getValue() != r->value) {
++errors;
++*pErrorCount;
printf("VerifyRangeReverse(@%" PRId64
", %s, %s) ERROR: Tree key '%s' has tree value '%s' but expected '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
cur->getKey().toString().c_str(),
cur->getValue().toString().c_str(),
r->value.toString().c_str());
break;
}
++r;
wait(cur->prev());
}
if (r != results.rend()) {
++errors;
++*pErrorCount;
printf("VerifyRangeReverse(@%" PRId64 ", %s, %s) ERROR: Tree range ended but written has '%s'\n",
v,
start.printable().c_str(),
end.printable().c_str(),
r->key.toString().c_str());
}
return errors;
}
// Verify the result of point reads for every set or cleared key at the given version
ACTOR Future<int> seekAll(VersionedBTree* btree,
Version v,
std::map<std::pair<std::string, Version>, Optional<std::string>>* written,
int* pErrorCount) {
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator i = written->cbegin();
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator iEnd = written->cend();
state int errors = 0;
state Reference<IStoreCursor> cur = btree->readAtVersion(v);
while (i != iEnd) {
state std::string key = i->first.first;
state Version ver = i->first.second;
if (ver == v) {
state Optional<std::string> val = i->second;
debug_printf("Verifying @%" PRId64 " '%s'\n", ver, key.c_str());
state Arena arena;
wait(cur->findEqual(KeyRef(arena, key)));
if (val.present()) {
if (!(cur->isValid() && cur->getKey() == key && cur->getValue() == val.get())) {
++errors;
++*pErrorCount;
if (!cur->isValid())
printf("Verify ERROR: key_not_found: '%s' -> '%s' @%" PRId64 "\n",
key.c_str(),
val.get().c_str(),
ver);
else if (cur->getKey() != key)
printf("Verify ERROR: key_incorrect: found '%s' expected '%s' @%" PRId64 "\n",
cur->getKey().toString().c_str(),
key.c_str(),
ver);
else if (cur->getValue() != val.get())
printf("Verify ERROR: value_incorrect: for '%s' found '%s' expected '%s' @%" PRId64 "\n",
cur->getKey().toString().c_str(),
cur->getValue().toString().c_str(),
val.get().c_str(),
ver);
}
} else {
if (cur->isValid() && cur->getKey() == key) {
++errors;
++*pErrorCount;
printf("Verify ERROR: cleared_key_found: '%s' -> '%s' @%" PRId64 "\n",
key.c_str(),
cur->getValue().toString().c_str(),
ver);
}
}
}
++i;
}
return errors;
}
// Verify the result of point reads for every set or cleared key at the given version
ACTOR Future<int> seekAllBTreeCursor(VersionedBTree* btree,
Version v,
std::map<std::pair<std::string, Version>, Optional<std::string>>* written,
int* pErrorCount) {
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator i = written->cbegin();
state std::map<std::pair<std::string, Version>, Optional<std::string>>::const_iterator iEnd = written->cend();
state int errors = 0;
state VersionedBTree::BTreeCursor cur;
wait(btree->initBTreeCursor(&cur, v));
while (i != iEnd) {
state std::string key = i->first.first;
state Version ver = i->first.second;
if (ver == v) {
state Optional<std::string> val = i->second;
debug_printf("Verifying @%" PRId64 " '%s'\n", ver, key.c_str());
state Arena arena;
wait(cur.seekGTE(RedwoodRecordRef(KeyRef(arena, key), 0), 0));
bool foundKey = cur.isValid() && cur.get().key == key;
bool hasValue = foundKey && cur.get().value.present();
if (val.present()) {
bool valueMatch = hasValue && cur.get().value.get() == val.get();
if (!foundKey || !hasValue || !valueMatch) {
++errors;
++*pErrorCount;
if (!foundKey) {
printf("Verify ERROR: key_not_found: '%s' -> '%s' @%" PRId64 "\n",
key.c_str(),
val.get().c_str(),
ver);
} else if (!hasValue) {
printf("Verify ERROR: value_not_found: '%s' -> '%s' @%" PRId64 "\n",
key.c_str(),
val.get().c_str(),
ver);
} else if (!valueMatch) {
printf("Verify ERROR: value_incorrect: for '%s' found '%s' expected '%s' @%" PRId64 "\n",
key.c_str(),
cur.get().value.get().toString().c_str(),
val.get().c_str(),
ver);
}
}
} else if (foundKey && hasValue) {
++errors;
++*pErrorCount;
printf("Verify ERROR: cleared_key_found: '%s' -> '%s' @%" PRId64 "\n",
key.c_str(),
cur.get().value.get().toString().c_str(),
ver);
}
}
++i;
}
return errors;
}
ACTOR Future<Void> verify(VersionedBTree* btree,
FutureStream<Version> vStream,
std::map<std::pair<std::string, Version>, Optional<std::string>>* written,
int* pErrorCount,
bool serial) {
state Future<int> fRangeAll;
state Future<int> fRangeRandom;
state Future<int> fSeekAll;
// Queue of committed versions still readable from btree
state std::deque<Version> committedVersions;
try {
loop {
state Version v = waitNext(vStream);
committedVersions.push_back(v);
// Remove expired versions
while (!committedVersions.empty() && committedVersions.front() < btree->getOldestVersion()) {
committedVersions.pop_front();
}
// Continue if the versions list is empty, which won't wait until it reaches the oldest readable
// btree version which will already be in vStream.
if (committedVersions.empty()) {
continue;
}
// Choose a random committed version.
v = committedVersions[deterministicRandom()->randomInt(0, committedVersions.size())];
debug_printf("Using committed version %" PRId64 "\n", v);
// Get a cursor at v so that v doesn't get expired between the possibly serial steps below.
state Reference<IStoreCursor> cur = btree->readAtVersion(v);
debug_printf("Verifying entire key range at version %" PRId64 "\n", v);
if (deterministicRandom()->coinflip()) {
fRangeAll =
verifyRange(btree, LiteralStringRef(""), LiteralStringRef("\xff\xff"), v, written, pErrorCount);
} else {
fRangeAll = verifyRangeBTreeCursor(
btree, LiteralStringRef(""), LiteralStringRef("\xff\xff"), v, written, pErrorCount);
}
if (serial) {
wait(success(fRangeAll));
}
Key begin = randomKV().key;
Key end = randomKV().key;
debug_printf(
"Verifying range (%s, %s) at version %" PRId64 "\n", toString(begin).c_str(), toString(end).c_str(), v);
if (deterministicRandom()->coinflip()) {
fRangeRandom = verifyRange(btree, begin, end, v, written, pErrorCount);
} else {
fRangeRandom = verifyRangeBTreeCursor(btree, begin, end, v, written, pErrorCount);
}
if (serial) {
wait(success(fRangeRandom));
}
debug_printf("Verifying seeks to each changed key at version %" PRId64 "\n", v);
if (deterministicRandom()->coinflip()) {
fSeekAll = seekAll(btree, v, written, pErrorCount);
} else {
fSeekAll = seekAllBTreeCursor(btree, v, written, pErrorCount);
}
if (serial) {
wait(success(fSeekAll));
}
wait(success(fRangeAll) && success(fRangeRandom) && success(fSeekAll));
printf("Verified version %" PRId64 ", %d errors\n", v, *pErrorCount);
if (*pErrorCount != 0)
break;
}
} catch (Error& e) {
if (e.code() != error_code_end_of_stream && e.code() != error_code_transaction_too_old) {
throw;
}
}
return Void();
}
// Does a random range read, doesn't trap/report errors
ACTOR Future<Void> randomReader(VersionedBTree* btree) {
try {
state Reference<IStoreCursor> cur;
loop {
wait(yield());
if (!cur || deterministicRandom()->random01() > .01) {
Version v = btree->getLastCommittedVersion();
cur = btree->readAtVersion(v);
}
state KeyValue kv = randomKV(10, 0);
wait(cur->findFirstEqualOrGreater(kv.key));
state int c = deterministicRandom()->randomInt(0, 100);
while (cur->isValid() && c-- > 0) {
wait(success(cur->next()));
wait(yield());
}
}
} catch (Error& e) {
if (e.code() != error_code_transaction_too_old) {
throw e;
}
}
return Void();
}
struct IntIntPair {
IntIntPair() {}
IntIntPair(int k, int v) : k(k), v(v) {}
IntIntPair(Arena& arena, const IntIntPair& toCopy) { *this = toCopy; }
struct Delta {
bool prefixSource;
bool deleted;
int dk;
int dv;
IntIntPair apply(const IntIntPair& base, Arena& arena) { return { base.k + dk, base.v + dv }; }
void setPrefixSource(bool val) { prefixSource = val; }
bool getPrefixSource() const { return prefixSource; }
void setDeleted(bool val) { deleted = val; }
bool getDeleted() const { return deleted; }
int size() const { return sizeof(Delta); }
std::string toString() const {
return format(
"DELTA{prefixSource=%d deleted=%d dk=%d(0x%x) dv=%d(0x%x)}", prefixSource, deleted, dk, dk, dv, dv);
}
};
// For IntIntPair, skipLen will be in units of fields, not bytes
int getCommonPrefixLen(const IntIntPair& other, int skip = 0) const {
if (k == other.k) {
if (v == other.v) {
return 2;
}
return 1;
}
return 0;
}
int compare(const IntIntPair& rhs, int skip = 0) const {
if (skip == 2) {
return 0;
}
int cmp = (skip > 0) ? 0 : (k - rhs.k);
if (cmp == 0) {
cmp = v - rhs.v;
}
return cmp;
}
bool operator==(const IntIntPair& rhs) const { return compare(rhs) == 0; }
bool operator!=(const IntIntPair& rhs) const { return compare(rhs) != 0; }
bool operator<(const IntIntPair& rhs) const { return compare(rhs) < 0; }
bool operator>(const IntIntPair& rhs) const { return compare(rhs) > 0; }
bool operator<=(const IntIntPair& rhs) const { return compare(rhs) <= 0; }
bool operator>=(const IntIntPair& rhs) const { return compare(rhs) >= 0; }
int deltaSize(const IntIntPair& base, int skipLen, bool worstcase) const { return sizeof(Delta); }
int writeDelta(Delta& d, const IntIntPair& base, int commonPrefix = -1) const {
d.prefixSource = false;
d.deleted = false;
d.dk = k - base.k;
d.dv = v - base.v;
return sizeof(Delta);
}
int k;
int v;
std::string toString() const { return format("{k=%d(0x%x) v=%d(0x%x)}", k, k, v, v); }
};
int deltaTest(RedwoodRecordRef rec, RedwoodRecordRef base) {
std::vector<uint8_t> buf(rec.key.size() + rec.value.orDefault(StringRef()).size() + 20);
RedwoodRecordRef::Delta& d = *(RedwoodRecordRef::Delta*)&buf.front();
Arena mem;
int expectedSize = rec.deltaSize(base, 0, false);
int deltaSize = rec.writeDelta(d, base);
RedwoodRecordRef decoded = d.apply(base, mem);
if (decoded != rec || expectedSize != deltaSize || d.size() != deltaSize) {
printf("\n");
printf("Base: %s\n", base.toString().c_str());
printf("Record: %s\n", rec.toString().c_str());
printf("Decoded: %s\n", decoded.toString().c_str());
printf("deltaSize(): %d\n", expectedSize);
printf("writeDelta(): %d\n", deltaSize);
printf("d.size(): %d\n", d.size());
printf("DeltaToString: %s\n", d.toString().c_str());
printf("RedwoodRecordRef::Delta test failure!\n");
ASSERT(false);
}
return deltaSize;
}
RedwoodRecordRef randomRedwoodRecordRef(const std::string& keyBuffer, const std::string& valueBuffer) {
RedwoodRecordRef rec;
rec.key = StringRef((uint8_t*)keyBuffer.data(), deterministicRandom()->randomInt(0, keyBuffer.size()));
if (deterministicRandom()->coinflip()) {
rec.value = StringRef((uint8_t*)valueBuffer.data(), deterministicRandom()->randomInt(0, valueBuffer.size()));
}
int versionIntSize = deterministicRandom()->randomInt(0, 8) * 8;
if (versionIntSize > 0) {
--versionIntSize;
int64_t max = ((int64_t)1 << versionIntSize) - 1;
rec.version = deterministicRandom()->randomInt64(0, max);
}
return rec;
}
TEST_CASE("/redwood/correctness/unit/RedwoodRecordRef") {
ASSERT(RedwoodRecordRef::Delta::LengthFormatSizes[0] == 3);
ASSERT(RedwoodRecordRef::Delta::LengthFormatSizes[1] == 4);
ASSERT(RedwoodRecordRef::Delta::LengthFormatSizes[2] == 6);
ASSERT(RedwoodRecordRef::Delta::LengthFormatSizes[3] == 8);
ASSERT(RedwoodRecordRef::Delta::VersionDeltaSizes[0] == 0);
ASSERT(RedwoodRecordRef::Delta::VersionDeltaSizes[1] == 4);
ASSERT(RedwoodRecordRef::Delta::VersionDeltaSizes[2] == 6);
ASSERT(RedwoodRecordRef::Delta::VersionDeltaSizes[3] == 8);
// Test pageID stuff.
{
LogicalPageID ids[] = { 1, 5 };
BTreePageIDRef id(ids, 2);
RedwoodRecordRef r;
r.setChildPage(id);
ASSERT(r.getChildPage() == id);
ASSERT(r.getChildPage().begin() == id.begin());
Standalone<RedwoodRecordRef> r2 = r;
ASSERT(r2.getChildPage() == id);
ASSERT(r2.getChildPage().begin() != id.begin());
}
deltaTest(RedwoodRecordRef(LiteralStringRef(""), 0, LiteralStringRef("")),
RedwoodRecordRef(LiteralStringRef(""), 0, LiteralStringRef("")));
deltaTest(RedwoodRecordRef(LiteralStringRef("abc"), 0, LiteralStringRef("")),
RedwoodRecordRef(LiteralStringRef("abc"), 0, LiteralStringRef("")));
deltaTest(RedwoodRecordRef(LiteralStringRef("abc"), 0, LiteralStringRef("")),
RedwoodRecordRef(LiteralStringRef("abcd"), 0, LiteralStringRef("")));
deltaTest(RedwoodRecordRef(LiteralStringRef("abcd"), 2, LiteralStringRef("")),
RedwoodRecordRef(LiteralStringRef("abc"), 2, LiteralStringRef("")));
deltaTest(RedwoodRecordRef(std::string(300, 'k'), 2, std::string(1e6, 'v')),
RedwoodRecordRef(std::string(300, 'k'), 2, LiteralStringRef("")));
deltaTest(RedwoodRecordRef(LiteralStringRef(""), 2, LiteralStringRef("")),
RedwoodRecordRef(LiteralStringRef(""), 1, LiteralStringRef("")));
deltaTest(RedwoodRecordRef(LiteralStringRef(""), 0xffff, LiteralStringRef("")),
RedwoodRecordRef(LiteralStringRef(""), 1, LiteralStringRef("")));
deltaTest(RedwoodRecordRef(LiteralStringRef(""), 1, LiteralStringRef("")),
RedwoodRecordRef(LiteralStringRef(""), 0xffff, LiteralStringRef("")));
deltaTest(RedwoodRecordRef(LiteralStringRef(""), 0xffffff, LiteralStringRef("")),
RedwoodRecordRef(LiteralStringRef(""), 1, LiteralStringRef("")));
deltaTest(RedwoodRecordRef(LiteralStringRef(""), 1, LiteralStringRef("")),
RedwoodRecordRef(LiteralStringRef(""), 0xffffff, LiteralStringRef("")));
Arena mem;
double start;
uint64_t total;
uint64_t count;
uint64_t i;
int64_t bytes;
std::string keyBuffer(30000, 'k');
std::string valueBuffer(70000, 'v');
start = timer();
count = 1000;
bytes = 0;
for (i = 0; i < count; ++i) {
RedwoodRecordRef a = randomRedwoodRecordRef(keyBuffer, valueBuffer);
RedwoodRecordRef b = randomRedwoodRecordRef(keyBuffer, valueBuffer);
bytes += deltaTest(a, b);
}
double elapsed = timer() - start;
printf("DeltaTest() on random large records %f M/s %f MB/s\n", count / elapsed / 1e6, bytes / elapsed / 1e6);
keyBuffer.resize(30);
valueBuffer.resize(100);
start = timer();
count = 1e6;
bytes = 0;
for (i = 0; i < count; ++i) {
RedwoodRecordRef a = randomRedwoodRecordRef(keyBuffer, valueBuffer);
RedwoodRecordRef b = randomRedwoodRecordRef(keyBuffer, valueBuffer);
bytes += deltaTest(a, b);
}
printf("DeltaTest() on random small records %f M/s %f MB/s\n", count / elapsed / 1e6, bytes / elapsed / 1e6);
RedwoodRecordRef rec1;
RedwoodRecordRef rec2;
rec1.key = LiteralStringRef("alksdfjaklsdfjlkasdjflkasdjfklajsdflk;ajsdflkajdsflkjadsf1");
rec2.key = LiteralStringRef("alksdfjaklsdfjlkasdjflkasdjfklajsdflk;ajsdflkajdsflkjadsf234");
rec1.version = deterministicRandom()->randomInt64(0, std::numeric_limits<Version>::max());
rec2.version = deterministicRandom()->randomInt64(0, std::numeric_limits<Version>::max());
start = timer();
total = 0;
count = 100e6;
for (i = 0; i < count; ++i) {
total += rec1.getCommonPrefixLen(rec2, 50);
}
printf("%" PRId64 " getCommonPrefixLen(skip=50) %f M/s\n", total, count / (timer() - start) / 1e6);
start = timer();
total = 0;
count = 100e6;
for (i = 0; i < count; ++i) {
total += rec1.getCommonPrefixLen(rec2, 0);
}
printf("%" PRId64 " getCommonPrefixLen(skip=0) %f M/s\n", total, count / (timer() - start) / 1e6);
char buf[1000];
RedwoodRecordRef::Delta& d = *(RedwoodRecordRef::Delta*)buf;
start = timer();
total = 0;
count = 100e6;
int commonPrefix = rec1.getCommonPrefixLen(rec2, 0);
for (i = 0; i < count; ++i) {
total += rec1.writeDelta(d, rec2, commonPrefix);
}
printf("%" PRId64 " writeDelta(commonPrefix=%d) %f M/s\n", total, commonPrefix, count / (timer() - start) / 1e6);
start = timer();
total = 0;
count = 10e6;
for (i = 0; i < count; ++i) {
total += rec1.writeDelta(d, rec2);
}
printf("%" PRId64 " writeDelta() %f M/s\n", total, count / (timer() - start) / 1e6);
start = timer();
total = 0;
count = 10e6;
for (i = 0; i < count; ++i) {
total += rec1.compare(rec2, 0);
}
printf("%" PRId64 " compare(skip=0) %f M/s\n", total, count / (timer() - start) / 1e6);
start = timer();
total = 0;
count = 10e6;
for (i = 0; i < count; ++i) {
total += rec1.compare(rec2, 50);
}
printf("%" PRId64 " compare(skip=50) %f M/s\n", total, count / (timer() - start) / 1e6);
return Void();
}
TEST_CASE("/redwood/correctness/unit/deltaTree/RedwoodRecordRef") {
// Sanity check on delta tree node format
ASSERT(DeltaTree<RedwoodRecordRef>::Node::headerSize(false) == 4);
ASSERT(DeltaTree<RedwoodRecordRef>::Node::headerSize(true) == 8);
const int N = deterministicRandom()->randomInt(200, 1000);
RedwoodRecordRef prev;
RedwoodRecordRef next(LiteralStringRef("\xff\xff\xff\xff"));
Arena arena;
std::set<RedwoodRecordRef> uniqueItems;
// Add random items to uniqueItems until its size is N
while (uniqueItems.size() < N) {
std::string k = deterministicRandom()->randomAlphaNumeric(30);
std::string v = deterministicRandom()->randomAlphaNumeric(30);
RedwoodRecordRef rec;
rec.key = StringRef(arena, k);
rec.version = deterministicRandom()->coinflip()
? deterministicRandom()->randomInt64(0, std::numeric_limits<Version>::max())
: invalidVersion;
if (deterministicRandom()->coinflip()) {
rec.value = StringRef(arena, v);
}
if (uniqueItems.count(rec) == 0) {
uniqueItems.insert(rec);
}
}
std::vector<RedwoodRecordRef> items(uniqueItems.begin(), uniqueItems.end());
int bufferSize = N * 100;
bool largeTree = bufferSize > DeltaTree<RedwoodRecordRef>::SmallSizeLimit;
DeltaTree<RedwoodRecordRef>* tree = (DeltaTree<RedwoodRecordRef>*)new uint8_t[bufferSize];
tree->build(bufferSize, &items[0], &items[items.size()], &prev, &next);
printf("Count=%d Size=%d InitialHeight=%d largeTree=%d\n",
(int)items.size(),
(int)tree->size(),
(int)tree->initialHeight,
largeTree);
debug_printf("Data(%p): %s\n", tree, StringRef((uint8_t*)tree, tree->size()).toHexString().c_str());
DeltaTree<RedwoodRecordRef>::Mirror r(tree, &prev, &next);
// Test delete/insert behavior for each item, making no net changes
printf("Testing seek/delete/insert for existing keys with random values\n");
ASSERT(tree->numItems == items.size());
for (auto rec : items) {
// Insert existing should fail
ASSERT(!r.insert(rec));
ASSERT(tree->numItems == items.size());
// Erase existing should succeed
ASSERT(r.erase(rec));
ASSERT(tree->numItems == items.size() - 1);
// Erase deleted should fail
ASSERT(!r.erase(rec));
ASSERT(tree->numItems == items.size() - 1);
// Insert deleted should succeed
ASSERT(r.insert(rec));
ASSERT(tree->numItems == items.size());
// Insert existing should fail
ASSERT(!r.insert(rec));
ASSERT(tree->numItems == items.size());
}
DeltaTree<RedwoodRecordRef>::Cursor fwd = r.getCursor();
DeltaTree<RedwoodRecordRef>::Cursor rev = r.getCursor();
DeltaTree<RedwoodRecordRef, RedwoodRecordRef::DeltaValueOnly>::Mirror rValuesOnly(tree, &prev, &next);
DeltaTree<RedwoodRecordRef, RedwoodRecordRef::DeltaValueOnly>::Cursor fwdValueOnly = rValuesOnly.getCursor();
printf("Verifying tree contents using forward, reverse, and value-only iterators\n");
ASSERT(fwd.moveFirst());
ASSERT(fwdValueOnly.moveFirst());
ASSERT(rev.moveLast());
int i = 0;
while (1) {
if (fwd.get() != items[i]) {
printf("forward iterator i=%d\n %s found\n %s expected\n",
i,
fwd.get().toString().c_str(),
items[i].toString().c_str());
printf("Delta: %s\n", fwd.node->raw->delta(largeTree).toString().c_str());
ASSERT(false);
}
if (rev.get() != items[items.size() - 1 - i]) {
printf("reverse iterator i=%d\n %s found\n %s expected\n",
i,
rev.get().toString().c_str(),
items[items.size() - 1 - i].toString().c_str());
printf("Delta: %s\n", rev.node->raw->delta(largeTree).toString().c_str());
ASSERT(false);
}
if (fwdValueOnly.get().value != items[i].value) {
printf("forward values-only iterator i=%d\n %s found\n %s expected\n",
i,
fwdValueOnly.get().toString().c_str(),
items[i].toString().c_str());
printf("Delta: %s\n", fwdValueOnly.node->raw->delta(largeTree).toString().c_str());
ASSERT(false);
}
++i;
bool more = fwd.moveNext();
ASSERT(fwdValueOnly.moveNext() == more);
ASSERT(rev.movePrev() == more);
ASSERT(fwd.valid() == more);
ASSERT(fwdValueOnly.valid() == more);
ASSERT(rev.valid() == more);
if (!fwd.valid()) {
break;
}
}
ASSERT(i == items.size());
{
DeltaTree<RedwoodRecordRef>::Mirror mirror(tree, &prev, &next);
DeltaTree<RedwoodRecordRef>::Cursor c = mirror.getCursor();
printf("Doing 20M random seeks using the same cursor from the same mirror.\n");
double start = timer();
for (int i = 0; i < 20000000; ++i) {
const RedwoodRecordRef& query = items[deterministicRandom()->randomInt(0, items.size())];
if (!c.seekLessThanOrEqual(query)) {
printf("Not found! query=%s\n", query.toString().c_str());
ASSERT(false);
}
if (c.get() != query) {
printf("Found incorrect node! query=%s found=%s\n",
query.toString().c_str(),
c.get().toString().c_str());
ASSERT(false);
}
}
double elapsed = timer() - start;
printf("Elapsed %f\n", elapsed);
}
{
printf("Doing 5M random seeks using 10k random cursors, each from a different mirror.\n");
double start = timer();
std::vector<DeltaTree<RedwoodRecordRef>::Mirror*> mirrors;
std::vector<DeltaTree<RedwoodRecordRef>::Cursor> cursors;
for (int i = 0; i < 10000; ++i) {
mirrors.push_back(new DeltaTree<RedwoodRecordRef>::Mirror(tree, &prev, &next));
cursors.push_back(mirrors.back()->getCursor());
}
for (int i = 0; i < 5000000; ++i) {
const RedwoodRecordRef& query = items[deterministicRandom()->randomInt(0, items.size())];
DeltaTree<RedwoodRecordRef>::Cursor& c = cursors[deterministicRandom()->randomInt(0, cursors.size())];
if (!c.seekLessThanOrEqual(query)) {
printf("Not found! query=%s\n", query.toString().c_str());
ASSERT(false);
}
if (c.get() != query) {
printf("Found incorrect node! query=%s found=%s\n",
query.toString().c_str(),
c.get().toString().c_str());
ASSERT(false);
}
}
double elapsed = timer() - start;
printf("Elapsed %f\n", elapsed);
}
return Void();
}
TEST_CASE("/redwood/correctness/unit/deltaTree/IntIntPair") {
const int N = 200;
IntIntPair prev = { 1, 0 };
IntIntPair next = { 10000, 10000 };
state std::function<IntIntPair()> randomPair = [&]() {
return IntIntPair(
{ deterministicRandom()->randomInt(prev.k, next.k), deterministicRandom()->randomInt(prev.v, next.v) });
};
// Build a set of N unique items, where no consecutive items are in the set, a requirement of the seek behavior tests.
std::set<IntIntPair> uniqueItems;
while (uniqueItems.size() < N) {
IntIntPair p = randomPair();
auto nextP = p; // also check if next highest/lowest key is not in set
nextP.v++;
auto prevP = p;
prevP.v--;
if (uniqueItems.count(p) == 0 && uniqueItems.count(nextP) == 0 && uniqueItems.count(prevP) == 0) {
uniqueItems.insert(p);
}
}
// Build tree of items
std::vector<IntIntPair> items(uniqueItems.begin(), uniqueItems.end());
int bufferSize = N * 2 * 20;
DeltaTree<IntIntPair>* tree = (DeltaTree<IntIntPair>*)new uint8_t[bufferSize];
int builtSize = tree->build(bufferSize, &items[0], &items[items.size()], &prev, &next);
ASSERT(builtSize <= bufferSize);
DeltaTree<IntIntPair>::Mirror r(tree, &prev, &next);
// Grow uniqueItems until tree is full, adding half of new items to toDelete
std::vector<IntIntPair> toDelete;
while (1) {
IntIntPair p = randomPair();
auto nextP = p; // also check if next highest/lowest key is not in the set
nextP.v++;
auto prevP = p;
prevP.v--;
if (uniqueItems.count(p) == 0 && uniqueItems.count(nextP) == 0 && uniqueItems.count(prevP) == 0) {
if (!r.insert(p)) {
break;
};
uniqueItems.insert(p);
if (deterministicRandom()->coinflip()) {
toDelete.push_back(p);
}
// printf("Inserted %s size=%d\n", items.back().toString().c_str(), tree->size());
}
}
ASSERT(tree->numItems > 2 * N);
ASSERT(tree->size() <= bufferSize);
// Update items vector
items = std::vector<IntIntPair>(uniqueItems.begin(), uniqueItems.end());
auto printItems = [&] {
for (int k = 0; k < items.size(); ++k) {
printf("%d %s\n", k, items[k].toString().c_str());
}
};
printf("Count=%d Size=%d InitialHeight=%d MaxHeight=%d\n",
(int)items.size(),
(int)tree->size(),
(int)tree->initialHeight,
(int)tree->maxHeight);
debug_printf("Data(%p): %s\n", tree, StringRef((uint8_t*)tree, tree->size()).toHexString().c_str());
// Iterate through items and tree forward and backward, verifying tree contents.
auto scanAndVerify = [&]() {
printf("Verify tree contents.\n");
DeltaTree<IntIntPair>::Cursor fwd = r.getCursor();
DeltaTree<IntIntPair>::Cursor rev = r.getCursor();
ASSERT(fwd.moveFirst());
ASSERT(rev.moveLast());
for (int i = 0; i < items.size(); ++i) {
if (fwd.get() != items[i]) {
printItems();
printf("forward iterator i=%d\n %s found\n %s expected\n",
i,
fwd.get().toString().c_str(),
items[i].toString().c_str());
ASSERT(false);
}
if (rev.get() != items[items.size() - 1 - i]) {
printItems();
printf("reverse iterator i=%d\n %s found\n %s expected\n",
i,
rev.get().toString().c_str(),
items[items.size() - 1 - i].toString().c_str());
ASSERT(false);
}
// Advance iterator, check scanning cursors for correct validity state
int j = i + 1;
bool end = j == items.size();
ASSERT(fwd.moveNext() == !end);
ASSERT(rev.movePrev() == !end);
ASSERT(fwd.valid() == !end);
ASSERT(rev.valid() == !end);
if (end) {
break;
}
}
};
// Verify tree contents
scanAndVerify();
// Create a new mirror, decoding the tree from scratch since insert() modified both the tree and the mirror
r = DeltaTree<IntIntPair>::Mirror(tree, &prev, &next);
scanAndVerify();
// For each randomly selected new item to be deleted, delete it from the DeltaTree and from uniqueItems
printf("Deleting some items\n");
for (auto p : toDelete) {
uniqueItems.erase(p);
DeltaTree<IntIntPair>::Cursor c = r.getCursor();
ASSERT(c.seekLessThanOrEqual(p));
c.erase();
}
// Update items vector
items = std::vector<IntIntPair>(uniqueItems.begin(), uniqueItems.end());
// Verify tree contents after deletions
scanAndVerify();
printf("Verifying insert/erase behavior for existing items\n");
// Test delete/insert behavior for each item, making no net changes
for (auto p : items) {
// Insert existing should fail
ASSERT(!r.insert(p));
// Erase existing should succeed
ASSERT(r.erase(p));
// Erase deleted should fail
ASSERT(!r.erase(p));
// Insert deleted should succeed
ASSERT(r.insert(p));
// Insert existing should fail
ASSERT(!r.insert(p));
}
// Tree contents should still match items vector
scanAndVerify();
printf("Verifying seek behaviors\n");
DeltaTree<IntIntPair>::Cursor s = r.getCursor();
// SeekLTE to each element
for (int i = 0; i < items.size(); ++i) {
IntIntPair p = items[i];
IntIntPair q = p;
ASSERT(s.seekLessThanOrEqual(q));
if (s.get() != p) {
printItems();
printf("seekLessThanOrEqual(%s) found %s expected %s\n",
q.toString().c_str(),
s.get().toString().c_str(),
p.toString().c_str());
ASSERT(false);
}
}
// SeekGTE to each element
for (int i = 0; i < items.size(); ++i) {
IntIntPair p = items[i];
IntIntPair q = p;
ASSERT(s.seekGreaterThanOrEqual(q));
if (s.get() != p) {
printItems();
printf("seekGreaterThanOrEqual(%s) found %s expected %s\n",
q.toString().c_str(),
s.get().toString().c_str(),
p.toString().c_str());
ASSERT(false);
}
}
// SeekLTE to the next possible int pair value after each element to make sure the base element is found
// Assumes no consecutive items are present in the set
for (int i = 0; i < items.size(); ++i) {
IntIntPair p = items[i];
IntIntPair q = p;
q.v++;
ASSERT(s.seekLessThanOrEqual(q));
if (s.get() != p) {
printItems();
printf("seekLessThanOrEqual(%s) found %s expected %s\n",
q.toString().c_str(),
s.get().toString().c_str(),
p.toString().c_str());
ASSERT(false);
}
}
// SeekGTE to the previous possible int pair value after each element to make sure the base element is found
// Assumes no consecutive items are present in the set
for (int i = 0; i < items.size(); ++i) {
IntIntPair p = items[i];
IntIntPair q = p;
q.v--;
ASSERT(s.seekGreaterThanOrEqual(q));
if (s.get() != p) {
printItems();
printf("seekGreaterThanOrEqual(%s) found %s expected %s\n",
q.toString().c_str(),
s.get().toString().c_str(),
p.toString().c_str());
ASSERT(false);
}
}
// SeekLTE to each element N times, using every element as a hint
for (int i = 0; i < items.size(); ++i) {
IntIntPair p = items[i];
IntIntPair q = p;
for (int j = 0; j < items.size(); ++j) {
ASSERT(s.seekLessThanOrEqual(items[j]));
ASSERT(s.seekLessThanOrEqual(q, 0, &s));
if (s.get() != p) {
printItems();
printf("i=%d j=%d\n", i, j);
printf("seekLessThanOrEqual(%s) found %s expected %s\n",
q.toString().c_str(),
s.get().toString().c_str(),
p.toString().c_str());
ASSERT(false);
}
}
}
// SeekLTE to each element's next possible value, using each element as a hint
// Assumes no consecutive items are present in the set
for (int i = 0; i < items.size(); ++i) {
IntIntPair p = items[i];
IntIntPair q = p;
q.v++;
for (int j = 0; j < items.size(); ++j) {
ASSERT(s.seekLessThanOrEqual(items[j]));
ASSERT(s.seekLessThanOrEqual(q, 0, &s));
if (s.get() != p) {
printItems();
printf("i=%d j=%d\n", i, j);
ASSERT(false);
}
}
}
auto skipSeekPerformance = [&](int jumpMax, bool old, bool useHint, int count) {
// Skip to a series of increasing items, jump by up to jumpMax units forward in the
// items, wrapping around to 0.
double start = timer();
s.moveFirst();
auto first = s;
int pos = 0;
for (int c = 0; c < count; ++c) {
int jump = deterministicRandom()->randomInt(0, jumpMax);
int newPos = pos + jump;
if (newPos >= items.size()) {
pos = 0;
newPos = jump;
s = first;
}
IntIntPair q = items[newPos];
++q.v;
if (old) {
if (useHint) {
s.seekLessThanOrEqualOld(q, 0, &s, newPos - pos);
} else {
s.seekLessThanOrEqualOld(q, 0, nullptr, 0);
}
} else {
if (useHint) {
s.seekLessThanOrEqual(q, 0, &s, newPos - pos);
} else {
s.seekLessThanOrEqual(q);
}
}
pos = newPos;
}
double elapsed = timer() - start;
printf("Seek/skip test, count=%d jumpMax=%d, items=%d, oldSeek=%d useHint=%d: Elapsed %f seconds %.2f M/s\n",
count,
jumpMax,
items.size(),
old,
useHint,
elapsed,
double(count) / elapsed / 1e6);
};
// Compare seeking to nearby elements with and without hints, using the old and new SeekLessThanOrEqual methods.
// TODO: Once seekLessThanOrEqual() with a hint is as fast as seekLessThanOrEqualOld, remove it.
skipSeekPerformance(8, true, false, 80e6);
skipSeekPerformance(8, true, true, 80e6);
skipSeekPerformance(8, false, false, 80e6);
skipSeekPerformance(8, false, true, 80e6);
// Repeatedly seek for one of a set of pregenerated random pairs and time it.
std::vector<IntIntPair> randomPairs;
randomPairs.reserve(10 * N);
for (int i = 0; i < 10 * N; ++i) {
randomPairs.push_back(randomPair());
}
// Random seeks
double start = timer();
for (int i = 0; i < 20000000; ++i) {
IntIntPair p = randomPairs[i % randomPairs.size()];
// Verify the result is less than or equal, and if seek fails then p must be lower than lowest (first) item
if (!s.seekLessThanOrEqual(p)) {
if (p >= items.front()) {
printf("Seek failed! query=%s front=%s\n", p.toString().c_str(), items.front().toString().c_str());
ASSERT(false);
}
} else if (s.get() > p) {
printf("Found incorrect node! query=%s found=%s\n", p.toString().c_str(), s.get().toString().c_str());
ASSERT(false);
}
}
double elapsed = timer() - start;
printf("Random seek test: Elapsed %f\n", elapsed);
return Void();
}
struct SimpleCounter {
SimpleCounter() : x(0), xt(0), t(timer()), start(t) {}
void operator+=(int n) { x += n; }
void operator++() { x++; }
int64_t get() { return x; }
double rate() {
double t2 = timer();
int r = (x - xt) / (t2 - t);
xt = x;
t = t2;
return r;
}
double avgRate() { return x / (timer() - start); }
int64_t x;
double t;
double start;
int64_t xt;
std::string toString() { return format("%" PRId64 "/%.2f/%.2f", x, rate() / 1e6, avgRate() / 1e6); }
};
TEST_CASE(":/redwood/performance/mutationBuffer") {
// This test uses pregenerated short random keys
int count = 10e6;
printf("Generating %d strings...\n", count);
Arena arena;
std::vector<KeyRef> strings;
while (strings.size() < count) {
strings.push_back(randomString(arena, 5));
}
printf("Inserting and then finding each string...\n", count);
double start = timer();
VersionedBTree::MutationBuffer m;
for (int i = 0; i < count; ++i) {
KeyRef key = strings[i];
auto a = m.insert(key);
auto b = m.lower_bound(key);
ASSERT(a == b);
m.erase(a, b);
}
double elapsed = timer() - start;
printf("count=%d elapsed=%f\n", count, elapsed);
return Void();
}
// This test is only useful with Arena debug statements which show when aligned buffers are allocated and freed.
TEST_CASE(":/redwood/pager/ArenaPage") {
Arena x;
printf("Making p\n");
Reference<ArenaPage> p(new ArenaPage(4096, 4096));
printf("Made p=%p\n", p->begin());
printf("Clearing p\n");
p.clear();
printf("Making p\n");
p = Reference<ArenaPage>(new ArenaPage(4096, 4096));
printf("Made p=%p\n", p->begin());
printf("Making x depend on p\n");
x.dependsOn(p->getArena());
printf("Clearing p\n");
p.clear();
printf("Clearing x\n");
x = Arena();
printf("Pointer should be freed\n");
return Void();
}
TEST_CASE("/redwood/correctness/btree") {
g_redwoodMetricsActor = Void(); // Prevent trace event metrics from starting
g_redwoodMetrics.clear();
state std::string fileName = params.get("fileName").orDefault("unittest_pageFile.redwood");
IPager2* pager;
state bool serialTest = params.getInt("serialTest").orDefault(deterministicRandom()->random01() < 0.25);
state bool shortTest = params.getInt("shortTest").orDefault(deterministicRandom()->random01() < 0.25);
state int pageSize =
shortTest ? 200 : (deterministicRandom()->coinflip() ? 4096 : deterministicRandom()->randomInt(200, 400));
state int64_t targetPageOps = params.getInt("targetPageOps").orDefault(shortTest ? 50000 : 1000000);
state bool pagerMemoryOnly =
params.getInt("pagerMemoryOnly").orDefault(shortTest && (deterministicRandom()->random01() < .001));
state int maxKeySize = params.getInt("maxKeySize").orDefault(deterministicRandom()->randomInt(1, pageSize * 2));
state int maxValueSize = params.getInt("maxValueSize").orDefault(randomSize(pageSize * 25));
state int maxCommitSize =
params.getInt("maxCommitSize")
.orDefault(shortTest ? 1000 : randomSize(std::min<int>((maxKeySize + maxValueSize) * 20000, 10e6)));
state double clearProbability =
params.getDouble("clearProbability").orDefault(deterministicRandom()->random01() * .1);
state double clearSingleKeyProbability =
params.getDouble("clearSingleKeyProbability").orDefault(deterministicRandom()->random01());
state double clearPostSetProbability =
params.getDouble("clearPostSetProbability").orDefault(deterministicRandom()->random01() * .1);
state double coldStartProbability =
params.getDouble("coldStartProbability").orDefault(pagerMemoryOnly ? 0 : (deterministicRandom()->random01()));
state double advanceOldVersionProbability =
params.getDouble("advanceOldVersionProbability").orDefault(deterministicRandom()->random01());
state int64_t cacheSizeBytes =
params.getInt("cacheSizeBytes")
.orDefault(pagerMemoryOnly ? 2e9
: (pageSize * deterministicRandom()->randomInt(1, (BUGGIFY ? 2 : 10000) + 1)));
state Version versionIncrement =
params.getInt("versionIncrement").orDefault(deterministicRandom()->randomInt64(1, 1e8));
state Version remapCleanupWindow =
params.getInt("remapCleanupWindow")
.orDefault(BUGGIFY ? 0 : deterministicRandom()->randomInt64(1, versionIncrement * 50));
state int maxVerificationMapEntries = params.getInt("maxVerificationMapEntries").orDefault(300e3);
printf("\n");
printf("targetPageOps: %" PRId64 "\n", targetPageOps);
printf("pagerMemoryOnly: %d\n", pagerMemoryOnly);
printf("serialTest: %d\n", serialTest);
printf("shortTest: %d\n", shortTest);
printf("pageSize: %d\n", pageSize);
printf("maxKeySize: %d\n", maxKeySize);
printf("maxValueSize: %d\n", maxValueSize);
printf("maxCommitSize: %d\n", maxCommitSize);
printf("clearProbability: %f\n", clearProbability);
printf("clearSingleKeyProbability: %f\n", clearSingleKeyProbability);
printf("clearPostSetProbability: %f\n", clearPostSetProbability);
printf("coldStartProbability: %f\n", coldStartProbability);
printf("advanceOldVersionProbability: %f\n", advanceOldVersionProbability);
printf("cacheSizeBytes: %s\n", cacheSizeBytes == 0 ? "default" : format("%" PRId64, cacheSizeBytes).c_str());
printf("versionIncrement: %" PRId64 "\n", versionIncrement);
printf("remapCleanupWindow: %" PRId64 "\n", remapCleanupWindow);
printf("maxVerificationMapEntries: %d\n", maxVerificationMapEntries);
printf("\n");
printf("Deleting existing test data...\n");
deleteFile(fileName);
printf("Initializing...\n");
pager = new DWALPager(pageSize, fileName, cacheSizeBytes, remapCleanupWindow, pagerMemoryOnly);
state VersionedBTree* btree = new VersionedBTree(pager, fileName);
wait(btree->init());
state std::map<std::pair<std::string, Version>, Optional<std::string>> written;
state std::set<Key> keys;
state Version lastVer = btree->getLatestVersion();
printf("Starting from version: %" PRId64 "\n", lastVer);
state Version version = lastVer + 1;
btree->setWriteVersion(version);
state SimpleCounter mutationBytes;
state SimpleCounter keyBytesInserted;
state SimpleCounter valueBytesInserted;
state SimpleCounter sets;
state SimpleCounter rangeClears;
state SimpleCounter keyBytesCleared;
state int errorCount;
state int mutationBytesThisCommit = 0;
state int mutationBytesTargetThisCommit = randomSize(maxCommitSize);
state PromiseStream<Version> committedVersions;
state Future<Void> verifyTask = verify(btree, committedVersions.getFuture(), &written, &errorCount, serialTest);
state Future<Void> randomTask = serialTest ? Void() : (randomReader(btree) || btree->getError());
committedVersions.send(lastVer);
state Future<Void> commit = Void();
state int64_t totalPageOps = 0;
while (totalPageOps < targetPageOps && written.size() < maxVerificationMapEntries) {
// Sometimes increment the version
if (deterministicRandom()->random01() < 0.10) {
++version;
btree->setWriteVersion(version);
}
// Sometimes do a clear range
if (deterministicRandom()->random01() < clearProbability) {
Key start = randomKV(maxKeySize, 1).key;
Key end = (deterministicRandom()->random01() < .01) ? keyAfter(start) : randomKV(maxKeySize, 1).key;
// Sometimes replace start and/or end with a close actual (previously used) value
if (deterministicRandom()->random01() < .10) {
auto i = keys.upper_bound(start);
if (i != keys.end())
start = *i;
}
if (deterministicRandom()->random01() < .10) {
auto i = keys.upper_bound(end);
if (i != keys.end())
end = *i;
}
// Do a single key clear based on probability or end being randomly chosen to be the same as begin
// (unlikely)
if (deterministicRandom()->random01() < clearSingleKeyProbability || end == start) {
end = keyAfter(start);
} else if (end < start) {
std::swap(end, start);
}
// Apply clear range to verification map
++rangeClears;
KeyRangeRef range(start, end);
debug_printf(" Mutation: Clear '%s' to '%s' @%" PRId64 "\n",
start.toString().c_str(),
end.toString().c_str(),
version);
auto e = written.lower_bound(std::make_pair(start.toString(), 0));
if (e != written.end()) {
auto last = e;
auto eEnd = written.lower_bound(std::make_pair(end.toString(), 0));
while (e != eEnd) {
auto w = *e;
++e;
// If e key is different from last and last was present then insert clear for last's key at version
if (last != eEnd &&
((e == eEnd || e->first.first != last->first.first) && last->second.present())) {
debug_printf(
" Mutation: Clearing key '%s' @%" PRId64 "\n", last->first.first.c_str(), version);
keyBytesCleared += last->first.first.size();
mutationBytes += last->first.first.size();
mutationBytesThisCommit += last->first.first.size();
// If the last set was at version then just make it not present
if (last->first.second == version) {
last->second.reset();
} else {
written[std::make_pair(last->first.first, version)].reset();
}
}
last = e;
}
}
btree->clear(range);
// Sometimes set the range start after the clear
if (deterministicRandom()->random01() < clearPostSetProbability) {
KeyValue kv = randomKV(0, maxValueSize);
kv.key = range.begin;
btree->set(kv);
written[std::make_pair(kv.key.toString(), version)] = kv.value.toString();
}
} else {
// Set a key
KeyValue kv = randomKV(maxKeySize, maxValueSize);
// Sometimes change key to a close previously used key
if (deterministicRandom()->random01() < .01) {
auto i = keys.upper_bound(kv.key);
if (i != keys.end())
kv.key = StringRef(kv.arena(), *i);
}
debug_printf(" Mutation: Set '%s' -> '%s' @%" PRId64 "\n",
kv.key.toString().c_str(),
kv.value.toString().c_str(),
version);
++sets;
keyBytesInserted += kv.key.size();
valueBytesInserted += kv.value.size();
mutationBytes += (kv.key.size() + kv.value.size());
mutationBytesThisCommit += (kv.key.size() + kv.value.size());
btree->set(kv);
written[std::make_pair(kv.key.toString(), version)] = kv.value.toString();
keys.insert(kv.key);
}
// Commit after any limits for this commit or the total test are reached
if (totalPageOps >= targetPageOps || written.size() >= maxVerificationMapEntries ||
mutationBytesThisCommit >= mutationBytesTargetThisCommit) {
// Wait for previous commit to finish
wait(commit);
printf("Last commit complete. Next commit %d bytes, %" PRId64 " bytes committed so far.",
mutationBytesThisCommit,
mutationBytes.get() - mutationBytesThisCommit);
printf(" Stats: Insert %.2f MB/s ClearedKeys %.2f MB/s Total %.2f\n",
(keyBytesInserted.rate() + valueBytesInserted.rate()) / 1e6,
keyBytesCleared.rate() / 1e6,
mutationBytes.rate() / 1e6);
Version v = version; // Avoid capture of version as a member of *this
// Sometimes advance the oldest version to close the gap between the oldest and latest versions by a random
// amount.
if (deterministicRandom()->random01() < advanceOldVersionProbability) {
btree->setOldestVersion(btree->getLastCommittedVersion() -
deterministicRandom()->randomInt64(
0, btree->getLastCommittedVersion() - btree->getOldestVersion() + 1));
}
commit = map(btree->commit(), [=, &ops = totalPageOps](Void) {
// Update pager ops before clearing metrics
ops += g_redwoodMetrics.pageOps();
printf("Committed %s PageOps %" PRId64 "/%" PRId64 " (%.2f%%) VerificationMapEntries %d/%d (%.2f%%)\n",
toString(v).c_str(),
ops,
targetPageOps,
ops * 100.0 / targetPageOps,
written.size(),
maxVerificationMapEntries,
written.size() * 100.0 / maxVerificationMapEntries);
printf("Committed:\n%s\n", g_redwoodMetrics.toString(true).c_str());
// Notify the background verifier that version is committed and therefore readable
committedVersions.send(v);
return Void();
});
if (serialTest) {
// Wait for commit, wait for verification, then start new verification
wait(commit);
committedVersions.sendError(end_of_stream());
debug_printf("Waiting for verification to complete.\n");
wait(verifyTask);
committedVersions = PromiseStream<Version>();
verifyTask = verify(btree, committedVersions.getFuture(), &written, &errorCount, serialTest);
}
mutationBytesThisCommit = 0;
mutationBytesTargetThisCommit = randomSize(maxCommitSize);
// Recover from disk at random
if (!pagerMemoryOnly && deterministicRandom()->random01() < coldStartProbability) {
printf("Recovering from disk after next commit.\n");
// Wait for outstanding commit
debug_printf("Waiting for outstanding commit\n");
wait(commit);
// Stop and wait for the verifier task
committedVersions.sendError(end_of_stream());
debug_printf("Waiting for verification to complete.\n");
wait(verifyTask);
debug_printf("Closing btree\n");
Future<Void> closedFuture = btree->onClosed();
btree->close();
wait(closedFuture);
printf("Reopening btree from disk.\n");
IPager2* pager = new DWALPager(pageSize, fileName, cacheSizeBytes, remapCleanupWindow);
btree = new VersionedBTree(pager, fileName);
wait(btree->init());
Version v = btree->getLatestVersion();
printf("Recovered from disk. Latest recovered version %" PRId64 " highest written version %" PRId64
"\n",
v,
version);
ASSERT(v == version);
// Create new promise stream and start the verifier again
committedVersions = PromiseStream<Version>();
verifyTask = verify(btree, committedVersions.getFuture(), &written, &errorCount, serialTest);
randomTask = randomReader(btree) || btree->getError();
committedVersions.send(v);
}
version += versionIncrement;
btree->setWriteVersion(version);
}
// Check for errors
ASSERT(errorCount == 0);
}
debug_printf("Waiting for outstanding commit\n");
wait(commit);
committedVersions.sendError(end_of_stream());
randomTask.cancel();
debug_printf("Waiting for verification to complete.\n");
wait(verifyTask);
// Check for errors
ASSERT(errorCount == 0);
// Reopen pager and btree with a remap cleanup window of 0 to reclaim all old pages
state Future<Void> closedFuture = btree->onClosed();
btree->close();
wait(closedFuture);
btree = new VersionedBTree(new DWALPager(pageSize, fileName, cacheSizeBytes, 0), fileName);
wait(btree->init());
wait(btree->clearAllAndCheckSanity());
closedFuture = btree->onClosed();
btree->close();
debug_printf("Closing.\n");
wait(closedFuture);
return Void();
}
ACTOR Future<Void> randomSeeks(VersionedBTree* btree, int count, char firstChar, char lastChar) {
state Version readVer = btree->getLatestVersion();
state int c = 0;
state double readStart = timer();
printf("Executing %d random seeks\n", count);
state Reference<IStoreCursor> cur = btree->readAtVersion(readVer);
while (c < count) {
state Key k = randomString(20, firstChar, lastChar);
wait(success(cur->findFirstEqualOrGreater(k)));
++c;
}
double elapsed = timer() - readStart;
printf("Random seek speed %d/s\n", int(count / elapsed));
return Void();
}
ACTOR Future<Void> randomScans(VersionedBTree* btree,
int count,
int width,
int readAhead,
char firstChar,
char lastChar) {
state Version readVer = btree->getLatestVersion();
state int c = 0;
state double readStart = timer();
printf("Executing %d random scans\n", count);
state Reference<IStoreCursor> cur = btree->readAtVersion(readVer);
state bool adaptive = readAhead < 0;
state int totalScanBytes = 0;
while (c++ < count) {
state Key k = randomString(20, firstChar, lastChar);
wait(success(cur->findFirstEqualOrGreater(k, readAhead)));
if (adaptive) {
readAhead = totalScanBytes / c;
}
state int w = width;
while (w > 0 && cur->isValid()) {
totalScanBytes += cur->getKey().size();
totalScanBytes += cur->getValue().size();
wait(cur->next());
--w;
}
}
double elapsed = timer() - readStart;
printf("Completed %d scans: readAhead=%d width=%d bytesRead=%d scansRate=%d/s\n",
count,
readAhead,
width,
totalScanBytes,
int(count / elapsed));
return Void();
}
TEST_CASE(":/redwood/correctness/pager/cow") {
state std::string pagerFile = "unittest_pageFile.redwood";
printf("Deleting old test data\n");
deleteFile(pagerFile);
int pageSize = 4096;
state IPager2* pager = new DWALPager(pageSize, pagerFile, 0, 0);
wait(success(pager->init()));
state LogicalPageID id = wait(pager->newPageID());
Reference<ArenaPage> p = pager->newPageBuffer();
memset(p->mutate(), (char)id, p->size());
pager->updatePage(id, p);
pager->setMetaKey(LiteralStringRef("asdfasdf"));
wait(pager->commit());
Reference<ArenaPage> p2 = wait(pager->readPage(id, true));
printf("%s\n", StringRef(p2->begin(), p2->size()).toHexString().c_str());
// TODO: Verify reads, do more writes and reads to make this a real pager validator
Future<Void> onClosed = pager->onClosed();
pager->close();
wait(onClosed);
return Void();
}
TEST_CASE(":/redwood/performance/set") {
state SignalableActorCollection actors;
g_redwoodMetricsActor = Void(); // Prevent trace event metrics from starting
g_redwoodMetrics.clear();
state std::string fileName = params.get("fileName").orDefault("unittest.redwood");
state int pageSize = params.getInt("pageSize").orDefault(SERVER_KNOBS->REDWOOD_DEFAULT_PAGE_SIZE);
state int64_t pageCacheBytes = params.getInt("pageCacheBytes").orDefault(FLOW_KNOBS->PAGE_CACHE_4K);
state int nodeCount = params.getInt("nodeCount").orDefault(1e9);
state int maxRecordsPerCommit = params.getInt("maxRecordsPerCommit").orDefault(20000);
state int maxKVBytesPerCommit = params.getInt("maxKVBytesPerCommit").orDefault(20e6);
state int64_t kvBytesTarget = params.getInt("kvBytesTarget").orDefault(4e9);
state int minKeyPrefixBytes = params.getInt("minKeyPrefixBytes").orDefault(25);
state int maxKeyPrefixBytes = params.getInt("maxKeyPrefixBytes").orDefault(25);
state int minValueSize = params.getInt("minValueSize").orDefault(100);
state int maxValueSize = params.getInt("maxValueSize").orDefault(500);
state int minConsecutiveRun = params.getInt("minConsecutiveRun").orDefault(1);
state int maxConsecutiveRun = params.getInt("maxConsecutiveRun").orDefault(100);
state char firstKeyChar = params.get("firstKeyChar").orDefault("a")[0];
state char lastKeyChar = params.get("lastKeyChar").orDefault("m")[0];
state Version remapCleanupWindow =
params.getInt("remapCleanupWindow").orDefault(SERVER_KNOBS->REDWOOD_REMAP_CLEANUP_WINDOW);
state bool openExisting = params.getInt("openExisting").orDefault(0);
state bool insertRecords = !openExisting || params.getInt("insertRecords").orDefault(0);
state int concurrentSeeks = params.getInt("concurrentSeeks").orDefault(64);
state int concurrentScans = params.getInt("concurrentScans").orDefault(64);
state int seeks = params.getInt("seeks").orDefault(1000000);
state int scans = params.getInt("scans").orDefault(20000);
printf("pageSize: %d\n", pageSize);
printf("pageCacheBytes: %" PRId64 "\n", pageCacheBytes);
printf("trailingIntegerIndexRange: %d\n", nodeCount);
printf("maxChangesPerCommit: %d\n", maxRecordsPerCommit);
printf("minKeyPrefixBytes: %d\n", minKeyPrefixBytes);
printf("maxKeyPrefixBytes: %d\n", maxKeyPrefixBytes);
printf("minConsecutiveRun: %d\n", minConsecutiveRun);
printf("maxConsecutiveRun: %d\n", maxConsecutiveRun);
printf("minValueSize: %d\n", minValueSize);
printf("maxValueSize: %d\n", maxValueSize);
printf("maxCommitSize: %d\n", maxKVBytesPerCommit);
printf("kvBytesTarget: %" PRId64 "\n", kvBytesTarget);
printf("KeyLexicon '%c' to '%c'\n", firstKeyChar, lastKeyChar);
printf("remapCleanupWindow: %" PRId64 "\n", remapCleanupWindow);
printf("concurrentScans: %d\n", concurrentScans);
printf("concurrentSeeks: %d\n", concurrentSeeks);
printf("seeks: %d\n", seeks);
printf("scans: %d\n", scans);
printf("fileName: %s\n", fileName.c_str());
printf("openExisting: %d\n", openExisting);
printf("insertRecords: %d\n", insertRecords);
if (!openExisting) {
printf("Deleting old test data\n");
deleteFile(fileName);
}
DWALPager* pager = new DWALPager(pageSize, fileName, pageCacheBytes, remapCleanupWindow);
state VersionedBTree* btree = new VersionedBTree(pager, fileName);
wait(btree->init());
printf("Initialized. StorageBytes=%s\n", btree->getStorageBytes().toString().c_str());
state int64_t kvBytesThisCommit = 0;
state int64_t kvBytesTotal = 0;
state int recordsThisCommit = 0;
state Future<Void> commit = Void();
state std::string value(maxValueSize, 'v');
printf("Starting.\n");
state double intervalStart = timer();
state double start = intervalStart;
if (insertRecords) {
while (kvBytesTotal < kvBytesTarget) {
wait(yield());
Version lastVer = btree->getLatestVersion();
state Version version = lastVer + 1;
btree->setWriteVersion(version);
state int changesThisVersion =
deterministicRandom()->randomInt(0, maxRecordsPerCommit - recordsThisCommit + 1);
while (changesThisVersion > 0 && kvBytesThisCommit < maxKVBytesPerCommit) {
KeyValue kv;
kv.key = randomString(kv.arena(),
deterministicRandom()->randomInt(minKeyPrefixBytes + sizeof(uint32_t),
maxKeyPrefixBytes + sizeof(uint32_t) + 1),
firstKeyChar,
lastKeyChar);
int32_t index = deterministicRandom()->randomInt(0, nodeCount);
int runLength = deterministicRandom()->randomInt(minConsecutiveRun, maxConsecutiveRun + 1);
while (runLength > 0 && changesThisVersion > 0) {
*(uint32_t*)(kv.key.end() - sizeof(uint32_t)) = bigEndian32(index++);
kv.value = StringRef((uint8_t*)value.data(),
deterministicRandom()->randomInt(minValueSize, maxValueSize + 1));
btree->set(kv);
--runLength;
--changesThisVersion;
kvBytesThisCommit += kv.key.size() + kv.value.size();
++recordsThisCommit;
}
wait(yield());
}
if (kvBytesThisCommit >= maxKVBytesPerCommit || recordsThisCommit >= maxRecordsPerCommit) {
btree->setOldestVersion(btree->getLastCommittedVersion());
wait(commit);
printf("Cumulative %.2f MB keyValue bytes written at %.2f MB/s\n",
kvBytesTotal / 1e6,
kvBytesTotal / (timer() - start) / 1e6);
// Avoid capturing via this to freeze counter values
int recs = recordsThisCommit;
int kvb = kvBytesThisCommit;
// Capturing invervalStart via this->intervalStart makes IDE's unhappy as they do not know about the
// actor state object
double* pIntervalStart = &intervalStart;
commit = map(btree->commit(), [=](Void result) {
printf("Committed:\n%s\n", g_redwoodMetrics.toString(true).c_str());
double elapsed = timer() - *pIntervalStart;
printf("Committed %d keyValueBytes in %d records in %f seconds, %.2f MB/s\n",
kvb,
recs,
elapsed,
kvb / elapsed / 1e6);
*pIntervalStart = timer();
return Void();
});
kvBytesTotal += kvBytesThisCommit;
kvBytesThisCommit = 0;
recordsThisCommit = 0;
}
}
wait(commit);
printf("Cumulative %.2f MB keyValue bytes written at %.2f MB/s\n",
kvBytesTotal / 1e6,
kvBytesTotal / (timer() - start) / 1e6);
printf("StorageBytes=%s\n", btree->getStorageBytes().toString().c_str());
}
printf("Warming cache with seeks\n");
for (int x = 0; x < concurrentSeeks; ++x) {
actors.add(randomSeeks(btree, seeks / concurrentSeeks, firstKeyChar, lastKeyChar));
}
wait(actors.signalAndReset());
printf("Stats:\n%s\n", g_redwoodMetrics.toString(true).c_str());
printf("Serial scans with adaptive readAhead...\n");
actors.add(randomScans(btree, scans, 50, -1, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats:\n%s\n", g_redwoodMetrics.toString(true).c_str());
printf("Serial scans with readAhead 3 pages...\n");
actors.add(randomScans(btree, scans, 50, 12000, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats:\n%s\n", g_redwoodMetrics.toString(true).c_str());
printf("Serial scans with readAhead 2 pages...\n");
actors.add(randomScans(btree, scans, 50, 8000, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats:\n%s\n", g_redwoodMetrics.toString(true).c_str());
printf("Serial scans with readAhead 1 page...\n");
actors.add(randomScans(btree, scans, 50, 4000, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats:\n%s\n", g_redwoodMetrics.toString(true).c_str());
printf("Serial scans...\n");
actors.add(randomScans(btree, scans, 50, 0, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats:\n%s\n", g_redwoodMetrics.toString(true).c_str());
printf("Parallel scans, concurrency=%d, no readAhead ...\n", concurrentScans);
for (int x = 0; x < concurrentScans; ++x) {
actors.add(randomScans(btree, scans / concurrentScans, 50, 0, firstKeyChar, lastKeyChar));
}
wait(actors.signalAndReset());
printf("Stats:\n%s\n", g_redwoodMetrics.toString(true).c_str());
printf("Serial seeks...\n");
actors.add(randomSeeks(btree, seeks, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats:\n%s\n", g_redwoodMetrics.toString(true).c_str());
printf("Parallel seeks, concurrency=%d ...\n", concurrentSeeks);
for (int x = 0; x < concurrentSeeks; ++x) {
actors.add(randomSeeks(btree, seeks / concurrentSeeks, firstKeyChar, lastKeyChar));
}
wait(actors.signalAndReset());
printf("Stats:\n%s\n", g_redwoodMetrics.toString(true).c_str());
Future<Void> closedFuture = btree->onClosed();
btree->close();
wait(closedFuture);
return Void();
}
struct PrefixSegment {
int length;
int cardinality;
std::string toString() const { return format("{%d bytes, %d choices}", length, cardinality); }
};
// Utility class for generating kv pairs under a prefix pattern
// It currently uses std::string in an abstraction breaking way.
struct KVSource {
KVSource() {}
typedef VectorRef<uint8_t> PrefixRef;
typedef Standalone<PrefixRef> Prefix;
std::vector<PrefixSegment> desc;
std::vector<std::vector<std::string>> segments;
std::vector<Prefix> prefixes;
std::vector<Prefix*> prefixesSorted;
std::string valueData;
int prefixLen;
int lastIndex;
// TODO there is probably a better way to do this
Prefix extraRangePrefix;
KVSource(const std::vector<PrefixSegment>& desc, int numPrefixes = 0) : desc(desc) {
if (numPrefixes == 0) {
numPrefixes = 1;
for (auto& p : desc) {
numPrefixes *= p.cardinality;
}
}
prefixLen = 0;
for (auto& s : desc) {
prefixLen += s.length;
std::vector<std::string> parts;
while (parts.size() < s.cardinality) {
parts.push_back(deterministicRandom()->randomAlphaNumeric(s.length));
}
segments.push_back(std::move(parts));
}
while (prefixes.size() < numPrefixes) {
std::string p;
for (auto& s : segments) {
p.append(s[deterministicRandom()->randomInt(0, s.size())]);
}
prefixes.push_back(PrefixRef((uint8_t*)p.data(), p.size()));
}
for (auto& p : prefixes) {
prefixesSorted.push_back(&p);
}
std::sort(prefixesSorted.begin(), prefixesSorted.end(), [](const Prefix* a, const Prefix* b) {
return KeyRef((uint8_t*)a->begin(), a->size()) < KeyRef((uint8_t*)b->begin(), b->size());
});
valueData = deterministicRandom()->randomAlphaNumeric(100000);
lastIndex = 0;
}
// Expands the chosen prefix in the prefix list to hold suffix,
// fills suffix with random bytes, and returns a reference to the string
KeyRef getKeyRef(int suffixLen) { return makeKey(randomPrefix(), suffixLen); }
// Like getKeyRef but uses the same prefix as the last randomly chosen prefix
KeyRef getAnotherKeyRef(int suffixLen, bool sorted = false) {
Prefix& p = sorted ? *prefixesSorted[lastIndex] : prefixes[lastIndex];
return makeKey(p, suffixLen);
}
// Like getKeyRef but gets a KeyRangeRef. If samePrefix, it returns a range from the same prefix,
// otherwise it returns a random range from the entire keyspace
// Can technically return an empty range with low probability
KeyRangeRef getKeyRangeRef(bool samePrefix, int suffixLen, bool sorted = false) {
KeyRef a, b;
a = getKeyRef(suffixLen);
// Copy a so that b's Prefix Arena allocation doesn't overwrite a if using the same prefix
extraRangePrefix.reserve(extraRangePrefix.arena(), a.size());
a.copyTo((uint8_t*)extraRangePrefix.begin());
a = KeyRef(extraRangePrefix.begin(), a.size());
if (samePrefix) {
b = getAnotherKeyRef(suffixLen, sorted);
} else {
b = getKeyRef(suffixLen);
}
if (a < b) {
return KeyRangeRef(a, b);
} else {
return KeyRangeRef(b, a);
}
}
// TODO unused, remove?
// Like getKeyRef but gets a KeyRangeRef for two keys covering the given number of sorted adjacent prefixes
KeyRangeRef getRangeRef(int prefixesCovered, int suffixLen) {
prefixesCovered = std::min<int>(prefixesCovered, prefixes.size());
int i = deterministicRandom()->randomInt(0, prefixesSorted.size() - prefixesCovered);
Prefix* begin = prefixesSorted[i];
Prefix* end = prefixesSorted[i + prefixesCovered];
return KeyRangeRef(makeKey(*begin, suffixLen), makeKey(*end, suffixLen));
}
KeyRef getValue(int len) { return KeyRef(valueData).substr(0, len); }
// Move lastIndex to the next position, wrapping around to 0
void nextPrefix() {
++lastIndex;
if (lastIndex == prefixes.size()) {
lastIndex = 0;
}
}
Prefix& randomPrefix() {
lastIndex = deterministicRandom()->randomInt(0, prefixes.size());
return prefixes[lastIndex];
}
static KeyRef makeKey(Prefix& p, int suffixLen) {
p.reserve(p.arena(), p.size() + suffixLen);
uint8_t* wptr = p.end();
for (int i = 0; i < suffixLen; ++i) {
*wptr++ = (uint8_t)deterministicRandom()->randomAlphaNumeric();
}
return KeyRef(p.begin(), p.size() + suffixLen);
}
int numPrefixes() const { return prefixes.size(); };
std::string toString() const {
return format("{prefixLen=%d prefixes=%d format=%s}", prefixLen, numPrefixes(), ::toString(desc).c_str());
}
};
ACTOR Future<StorageBytes> getStableStorageBytes(IKeyValueStore* kvs) {
state StorageBytes sb = kvs->getStorageBytes();
// Wait for StorageBytes used metric to stabilize
loop {
wait(kvs->commit());
StorageBytes sb2 = kvs->getStorageBytes();
bool stable = sb2.used == sb.used;
sb = sb2;
if (stable) {
break;
}
}
return sb;
}
ACTOR Future<Void> prefixClusteredInsert(IKeyValueStore* kvs,
int suffixSize,
int valueSize,
KVSource source,
int recordCountTarget,
bool usePrefixesInOrder,
bool clearAfter) {
state int commitTarget = 5e6;
state int recordSize = source.prefixLen + suffixSize + valueSize;
state int64_t kvBytesTarget = (int64_t)recordCountTarget * recordSize;
state int recordsPerPrefix = recordCountTarget / source.numPrefixes();
printf("\nstoreType: %d\n", kvs->getType());
printf("commitTarget: %d\n", commitTarget);
printf("prefixSource: %s\n", source.toString().c_str());
printf("usePrefixesInOrder: %d\n", usePrefixesInOrder);
printf("suffixSize: %d\n", suffixSize);
printf("valueSize: %d\n", valueSize);
printf("recordSize: %d\n", recordSize);
printf("recordsPerPrefix: %d\n", recordsPerPrefix);
printf("recordCountTarget: %d\n", recordCountTarget);
printf("kvBytesTarget: %" PRId64 "\n", kvBytesTarget);
state int64_t kvBytes = 0;
state int64_t kvBytesTotal = 0;
state int records = 0;
state Future<Void> commit = Void();
state std::string value = deterministicRandom()->randomAlphaNumeric(1e6);
wait(kvs->init());
state double intervalStart = timer();
state double start = intervalStart;
state std::function<void()> stats = [&]() {
double elapsed = timer() - start;
printf("Cumulative stats: %.2f seconds %.2f MB keyValue bytes %d records %.2f MB/s %.2f rec/s\r",
elapsed,
kvBytesTotal / 1e6,
records,
kvBytesTotal / elapsed / 1e6,
records / elapsed);
fflush(stdout);
};
while (kvBytesTotal < kvBytesTarget) {
wait(yield());
state int i;
for (i = 0; i < recordsPerPrefix; ++i) {
KeyValueRef kv(source.getAnotherKeyRef(suffixSize, usePrefixesInOrder), source.getValue(valueSize));
kvs->set(kv);
kvBytes += kv.expectedSize();
++records;
if (kvBytes >= commitTarget) {
wait(commit);
stats();
commit = kvs->commit();
kvBytesTotal += kvBytes;
if (kvBytesTotal >= kvBytesTarget) {
break;
}
kvBytes = 0;
}
}
// Use every prefix, one at a time
source.nextPrefix();
}
wait(commit);
// TODO is it desired that not all records are committed? This could commit again to ensure any records set() since
// the last commit are persisted. For the purposes of how this is used currently, I don't think it matters though
stats();
printf("\n");
intervalStart = timer();
StorageBytes sb = wait(getStableStorageBytes(kvs));
printf("storageBytes: %s (stable after %.2f seconds)\n", toString(sb).c_str(), timer() - intervalStart);
if (clearAfter) {
printf("Clearing all keys\n");
intervalStart = timer();
kvs->clear(KeyRangeRef(LiteralStringRef(""), LiteralStringRef("\xff")));
state StorageBytes sbClear = wait(getStableStorageBytes(kvs));
printf("Cleared all keys in %.2f seconds, final storageByte: %s\n",
timer() - intervalStart,
toString(sbClear).c_str());
}
return Void();
}
ACTOR Future<Void> sequentialInsert(IKeyValueStore* kvs, int prefixLen, int valueSize, int recordCountTarget) {
state int commitTarget = 5e6;
state KVSource source({ { prefixLen, 1 } });
state int recordSize = source.prefixLen + sizeof(uint64_t) + valueSize;
state int64_t kvBytesTarget = (int64_t)recordCountTarget * recordSize;
printf("\nstoreType: %d\n", kvs->getType());
printf("commitTarget: %d\n", commitTarget);
printf("valueSize: %d\n", valueSize);
printf("recordSize: %d\n", recordSize);
printf("recordCountTarget: %d\n", recordCountTarget);
printf("kvBytesTarget: %" PRId64 "\n", kvBytesTarget);
state int64_t kvBytes = 0;
state int64_t kvBytesTotal = 0;
state int records = 0;
state Future<Void> commit = Void();
state std::string value = deterministicRandom()->randomAlphaNumeric(1e6);
wait(kvs->init());
state double intervalStart = timer();
state double start = intervalStart;
state std::function<void()> stats = [&]() {
double elapsed = timer() - start;
printf("Cumulative stats: %.2f seconds %.2f MB keyValue bytes %d records %.2f MB/s %.2f rec/s\r",
elapsed,
kvBytesTotal / 1e6,
records,
kvBytesTotal / elapsed / 1e6,
records / elapsed);
fflush(stdout);
};
state uint64_t c = 0;
state Key key = source.getKeyRef(sizeof(uint64_t));
while (kvBytesTotal < kvBytesTarget) {
wait(yield());
*(uint64_t*)(key.end() - sizeof(uint64_t)) = bigEndian64(c);
KeyValueRef kv(key, source.getValue(valueSize));
kvs->set(kv);
kvBytes += kv.expectedSize();
++records;
if (kvBytes >= commitTarget) {
wait(commit);
stats();
commit = kvs->commit();
kvBytesTotal += kvBytes;
if (kvBytesTotal >= kvBytesTarget) {
break;
}
kvBytes = 0;
}
++c;
}
wait(commit);
stats();
printf("\n");
return Void();
}
Future<Void> closeKVS(IKeyValueStore* kvs) {
Future<Void> closed = kvs->onClosed();
kvs->close();
return closed;
}
ACTOR Future<Void> doPrefixInsertComparison(int suffixSize,
int valueSize,
int recordCountTarget,
bool usePrefixesInOrder,
KVSource source) {
deleteFile("test.redwood");
wait(delay(5));
state IKeyValueStore* redwood = openKVStore(KeyValueStoreType::SSD_REDWOOD_V1, "test.redwood", UID(), 0);
wait(prefixClusteredInsert(redwood, suffixSize, valueSize, source, recordCountTarget, usePrefixesInOrder, true));
wait(closeKVS(redwood));
printf("\n");
deleteFile("test.sqlite");
deleteFile("test.sqlite-wal");
wait(delay(5));
state IKeyValueStore* sqlite = openKVStore(KeyValueStoreType::SSD_BTREE_V2, "test.sqlite", UID(), 0);
wait(prefixClusteredInsert(sqlite, suffixSize, valueSize, source, recordCountTarget, usePrefixesInOrder, true));
wait(closeKVS(sqlite));
printf("\n");
return Void();
}
TEST_CASE(":/redwood/performance/prefixSizeComparison") {
state int suffixSize = params.getInt("suffixSize").orDefault(12);
state int valueSize = params.getInt("valueSize").orDefault(100);
state int recordCountTarget = params.getInt("recordCountTarget").orDefault(100e6);
state bool usePrefixesInOrder = params.getInt("usePrefixesInOrder").orDefault(0);
wait(doPrefixInsertComparison(
suffixSize, valueSize, recordCountTarget, usePrefixesInOrder, KVSource({ { 10, 100000 } })));
wait(doPrefixInsertComparison(
suffixSize, valueSize, recordCountTarget, usePrefixesInOrder, KVSource({ { 16, 100000 } })));
wait(doPrefixInsertComparison(
suffixSize, valueSize, recordCountTarget, usePrefixesInOrder, KVSource({ { 32, 100000 } })));
wait(doPrefixInsertComparison(suffixSize,
valueSize,
recordCountTarget,
usePrefixesInOrder,
KVSource({ { 4, 5 }, { 12, 1000 }, { 8, 5 }, { 8, 4 } })));
return Void();
}
TEST_CASE(":/redwood/performance/sequentialInsert") {
state int prefixLen = params.getInt("prefixLen").orDefault(30);
state int valueSize = params.getInt("valueSize").orDefault(100);
state int recordCountTarget = params.getInt("recordCountTarget").orDefault(100e6);
deleteFile("test.redwood");
wait(delay(5));
state IKeyValueStore* redwood = openKVStore(KeyValueStoreType::SSD_REDWOOD_V1, "test.redwood", UID(), 0);
wait(sequentialInsert(redwood, prefixLen, valueSize, recordCountTarget));
wait(closeKVS(redwood));
printf("\n");
return Void();
}
// singlePrefix forces the range read to have the start and end key with the same prefix
ACTOR Future<Void> randomRangeScans(IKeyValueStore* kvs,
int suffixSize,
KVSource source,
int valueSize,
int recordCountTarget,
bool singlePrefix,
int rowLimit) {
printf("\nstoreType: %d\n", kvs->getType());
printf("prefixSource: %s\n", source.toString().c_str());
printf("suffixSize: %d\n", suffixSize);
printf("recordCountTarget: %d\n", recordCountTarget);
printf("singlePrefix: %d\n", singlePrefix);
printf("rowLimit: %d\n", rowLimit);
state int64_t recordSize = source.prefixLen + suffixSize + valueSize;
state int64_t bytesRead = 0;
state int64_t recordsRead = 0;
state int queries = 0;
state int64_t nextPrintRecords = 1e5;
state double start = timer();
state std::function<void()> stats = [&]() {
double elapsed = timer() - start;
printf("Cumulative stats: %.2f seconds %d queries %.2f MB %d records %.2f qps %.2f MB/s %.2f rec/s\r\n",
elapsed,
queries,
bytesRead / 1e6,
recordsRead,
queries / elapsed,
bytesRead / elapsed / 1e6,
recordsRead / elapsed);
fflush(stdout);
};
while (recordsRead < recordCountTarget) {
KeyRangeRef range = source.getKeyRangeRef(singlePrefix, suffixSize);
int rowLim = (deterministicRandom()->randomInt(0, 2) != 0) ? rowLimit : -rowLimit;
RangeResult result = wait(kvs->readRange(range, rowLim));
recordsRead += result.size();
bytesRead += result.size() * recordSize;
++queries;
// log stats with exponential backoff
if (recordsRead >= nextPrintRecords) {
stats();
nextPrintRecords *= 2;
}
}
stats();
printf("\n");
return Void();
}
TEST_CASE("!/redwood/performance/randomRangeScans") {
state int prefixLen = 30;
state int suffixSize = 12;
state int valueSize = 100;
// TODO change to 100e8 after figuring out no-disk redwood mode
state int writeRecordCountTarget = 1e6;
state int queryRecordTarget = 1e7;
state int writePrefixesInOrder = false;
state KVSource source({ { prefixLen, 1000 } });
deleteFile("test.redwood");
wait(delay(5));
state IKeyValueStore* redwood = openKVStore(KeyValueStoreType::SSD_REDWOOD_V1, "test.redwood", UID(), 0);
wait(prefixClusteredInsert(
redwood, suffixSize, valueSize, source, writeRecordCountTarget, writePrefixesInOrder, false));
// divide targets for tiny queries by 10 because they are much slower
wait(randomRangeScans(redwood, suffixSize, source, valueSize, queryRecordTarget / 10, true, 10));
wait(randomRangeScans(redwood, suffixSize, source, valueSize, queryRecordTarget, true, 1000));
wait(randomRangeScans(redwood, suffixSize, source, valueSize, queryRecordTarget / 10, false, 100));
wait(randomRangeScans(redwood, suffixSize, source, valueSize, queryRecordTarget, false, 10000));
wait(randomRangeScans(redwood, suffixSize, source, valueSize, queryRecordTarget, false, 1000000));
wait(closeKVS(redwood));
printf("\n");
return Void();
}
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