foundationdb/fdbserver/VersionedBTree.actor.cpp

6268 lines
217 KiB
C++

/*
* 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/crc32c.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>
// 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{%" PRId64 "}", id);
}
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.begin(), v.end());
}
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>";
}
// 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 {
enum Mode {
NONE,
POP,
READONLY,
WRITE
};
// The current page being read or written to
LogicalPageID pageID;
// The first page ID to be written to the pager, if this cursor has written anything
LogicalPageID firstPageIDWritten;
// Offset after RawPage header to next read from or write to
int offset;
// A read cursor will not read this page (or beyond)
LogicalPageID endPageID;
Reference<IPage> page;
FIFOQueue *queue;
Future<Void> operation;
Mode mode;
Cursor() : mode(NONE) {
}
// Initialize a cursor.
void init(FIFOQueue *q = nullptr, Mode m = NONE, LogicalPageID initialPageID = invalidLogicalPageID, int readOffset = 0, LogicalPageID endPage = invalidLogicalPageID) {
if(operation.isValid()) {
operation.cancel();
}
queue = q;
mode = m;
firstPageIDWritten = invalidLogicalPageID;
offset = readOffset;
endPageID = endPage;
page.clear();
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;
operation = (pageID == endPageID) ? Void() : loadPage();
}
else {
pageID = invalidLogicalPageID;
ASSERT(mode == WRITE || (initialPageID == invalidLogicalPageID && readOffset == 0 && endPage == invalidLogicalPageID));
operation = Void();
}
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;
// 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);
}
~Cursor() {
operation.cancel();
}
std::string toString() const {
if(mode == WRITE) {
return format("{WriteCursor %s:%p pos=%s:%d endOffset=%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 endOffset=%d endPage=%s}", queue->name.c_str(), this, ::toString(pageID).c_str(), offset, page ? raw()->endOffset : -1, ::toString(endPageID).c_str());
}
ASSERT(mode == NONE);
return format("{NullCursor=%p}", this);
}
#pragma pack(push, 1)
struct RawPage {
LogicalPageID nextPageID;
uint16_t nextOffset;
uint16_t endOffset;
uint8_t * begin() {
return (uint8_t *)(this + 1);
}
};
#pragma pack(pop)
Future<Void> notBusy() {
return operation;
}
// Returns true if any items have been written to the last page
bool pendingWrites() 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;
}
Future<Void> loadPage() {
ASSERT(mode == POP | mode == READONLY);
debug_printf("FIFOQueue::Cursor(%s) loadPage\n", toString().c_str());
return map(queue->pager->readPage(pageID, true), [=](Reference<IPage> p) {
page = p;
debug_printf("FIFOQueue::Cursor(%s) loadPage done\n", toString().c_str());
return Void();
});
}
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.
// 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\n", toString().c_str());
writePage();
}
pageID = newPageID;
offset = newOffset;
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, Future<Void> start) {
ASSERT(self->mode == WRITE);
// Wait for the previous operation to finish
state Future<Void> previous = self->operation;
wait(start);
wait(previous);
state int bytesNeeded = Codec::bytesNeeded(item);
if(self->pageID == invalidLogicalPageID || self->offset + bytesNeeded > self->queue->dataBytesPerPage) {
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;
wait(yield());
}
debug_printf("FIFOQueue::Cursor(%s) before write(%s)\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;
return Void();
}
void write(const T &item) {
Promise<Void> p;
operation = write_impl(this, item, p.getFuture());
p.send(Void());
}
// Read the next item at the cursor (if <= upperBound), moving to a new page first if the current page is exhausted
ACTOR static Future<Optional<T>> readNext_impl(Cursor *self, Optional<T> upperBound, Future<Void> start) {
ASSERT(self->mode == POP || self->mode == READONLY);
// Wait for the previous operation to finish
state Future<Void> previous = self->operation;
wait(start);
wait(previous);
debug_printf("FIFOQueue::Cursor(%s) readNext begin\n", self->toString().c_str());
if(self->pageID == invalidLogicalPageID || self->pageID == self->endPageID) {
debug_printf("FIFOQueue::Cursor(%s) readNext returning nothing\n", self->toString().c_str());
return Optional<T>();
}
// We now know we are pointing to PageID and it should be read and used, but it may not be loaded yet.
if(!self->page) {
wait(self->loadPage());
wait(yield());
}
auto p = self->raw();
debug_printf("FIFOQueue::Cursor(%s) readNext reading at current position\n", self->toString().c_str());
ASSERT(self->offset < p->endOffset);
int bytesRead;
T result = Codec::readFromBytes(p->begin() + self->offset, bytesRead);
if(upperBound.present() && upperBound.get() < result) {
debug_printf("FIFOQueue::Cursor(%s) not popping %s, exceeds upper bound %s\n",
self->toString().c_str(), ::toString(result).c_str(), ::toString(upperBound.get()).c_str());
return Optional<T>();
}
self->offset += bytesRead;
if(self->mode == POP) {
--self->queue->numEntries;
}
debug_printf("FIFOQueue::Cursor(%s) after read of %s\n", self->toString().c_str(), ::toString(result).c_str());
ASSERT(self->offset <= p->endOffset);
if(self->offset == p->endOffset) {
debug_printf("FIFOQueue::Cursor(%s) Page exhausted\n", self->toString().c_str());
LogicalPageID oldPageID = self->pageID;
self->pageID = p->nextPageID;
self->offset = p->nextOffset;
if(self->mode == POP) {
--self->queue->numPages;
}
self->page.clear();
debug_printf("FIFOQueue::Cursor(%s) readNext page exhausted, moved to new page\n", self->toString().c_str());
if(self->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 page 0 because they can be reused after the next commit.
self->queue->pager->freePage(oldPageID, 0);
}
}
debug_printf("FIFOQueue(%s) %s(upperBound=%s) -> %s\n", self->queue->name.c_str(), (self->mode == POP ? "pop" : "peek"), ::toString(upperBound).c_str(), ::toString(result).c_str());
return result;
}
// Read and move past the next item if is <= upperBound or if upperBound is not present
Future<Optional<T>> readNext(const Optional<T> &upperBound = {}) {
if(mode == NONE) {
return Optional<T>();
}
Promise<Void> p;
Future<Optional<T>> read = readNext_impl(this, upperBound, p.getFuture());
operation = success(read);
p.send(Void());
return read;
}
};
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;
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;
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);
}
// 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);
}
// Wait until the most recently started operations on each cursor as of now are ready
Future<Void> notBusy() {
return headWriter.notBusy() && headReader.notBusy() && tailWriter.notBusy() && ready(newTailPage);
}
// Returns true if any most recently started operations on any cursors are not ready
bool busy() {
return !headWriter.notBusy().isReady() || !headReader.notBusy().isReady() || !tailWriter.notBusy().isReady() || !newTailPage.isReady();
}
// 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.
//
// 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->busy();
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(self->newTailPage.isReady() && self->newTailPage.get() == invalidLogicalPageID && self->tailWriter.pendingWrites()) {
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(!busy());
// 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.notBusy().isReady());
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.pendingWrites()) {
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;
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));
}
class FastAllocatedPage : public IPage, public FastAllocated<FastAllocatedPage>, ReferenceCounted<FastAllocatedPage> {
public:
// Create a fast-allocated page with size total bytes INCLUDING checksum
FastAllocatedPage(int size, int bufferSize) : logicalSize(size), bufferSize(bufferSize) {
buffer = (uint8_t *)allocateFast(bufferSize);
// Mark any unused page portion defined
VALGRIND_MAKE_MEM_DEFINED(buffer + logicalSize, bufferSize - logicalSize);
};
virtual ~FastAllocatedPage() {
freeFast(bufferSize, buffer);
}
// Usable size, without checksum
int size() const {
return logicalSize - sizeof(Checksum);
}
uint8_t const* begin() const {
return buffer;
}
uint8_t* mutate() {
return buffer;
}
void addref() const {
ReferenceCounted<FastAllocatedPage>::addref();
}
void delref() const {
ReferenceCounted<FastAllocatedPage>::delref();
}
typedef uint32_t Checksum;
Checksum & getChecksum() {
return *(Checksum *)(buffer + size());
}
Checksum calculateChecksum(LogicalPageID pageID) {
return crc32c_append(pageID, buffer, size());
}
void updateChecksum(LogicalPageID pageID) {
getChecksum() = calculateChecksum(pageID);
}
bool verifyChecksum(LogicalPageID pageID) {
return getChecksum() == calculateChecksum(pageID);
}
private:
int logicalSize;
int bufferSize;
uint8_t *buffer;
};
// Holds an index of recently used objects.
// ObjectType must have the method
// bool evictable() const; // return true if the entry can be evicted
// Future<Void> onEvictable() const; // ready when entry can be evicted
// indicating if it is safe to evict.
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;
};
public:
ObjectCache(int sizeLimit = 0) : sizeLimit(sizeLimit), cacheHits(0), cacheMisses(0), noHitEvictions(0) {
}
void setSizeLimit(int n) {
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;
return &i->second.item;
}
return nullptr;
}
// Get the object for i or create a new one.
// After a get(), the object for i is the last in evictionOrder.
ObjectType & get(const IndexType &index, bool noHit = 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;
++cacheHits;
}
// Move the entry to the back of the eviction order
evictionOrder.erase(evictionOrder.iterator_to(entry));
evictionOrder.push_back(entry);
}
else {
++cacheMisses;
// Finish initializing entry
entry.index = index;
entry.hits = noHit ? 0 : 1;
// Insert the newly created Entry at the back of the eviction order
evictionOrder.push_back(entry);
// If the cache is too big, try to evict the first Entry in the eviction order
if(cache.size() > sizeLimit) {
Entry &toEvict = evictionOrder.front();
debug_printf("Trying to evict %s to make room for %s\n", toString(toEvict.index).c_str(), toString(index).c_str());
// Don't evict the entry that was just added as then we can't return a reference to it.
if(toEvict.index != index && toEvict.item.evictable()) {
if(toEvict.hits == 0) {
++noHitEvictions;
}
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 std::unordered_map<IndexType, Entry> cache;
state boost::intrusive::list<Entry> evictionOrder;
// Swap cache contents to local state vars
cache.swap(self->cache);
evictionOrder.swap(self->evictionOrder);
state typename boost::intrusive::list<Entry>::iterator i = evictionOrder.begin();
state typename boost::intrusive::list<Entry>::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() {
return clear_impl(this);
}
int count() const {
ASSERT(evictionOrder.size() == cache.size());
return evictionOrder.size();
}
private:
int64_t sizeLimit;
int64_t cacheHits;
int64_t cacheMisses;
int64_t noHitEvictions;
// TODO: Use boost intrusive unordered set instead, with a comparator that only considers entry.index
std::unordered_map<IndexType, Entry> cache;
boost::intrusive::list<Entry> 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 FastAllocatedPage Page;
typedef FIFOQueue<LogicalPageID> LogicalPageQueueT;
#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 {
Version version;
LogicalPageID originalPageID;
LogicalPageID newPageID;
bool operator<(const RemappedPage &rhs) {
return version < rhs.version;
}
std::string toString() const {
return format("RemappedPage(%s -> %s @%" PRId64 "}", ::toString(originalPageID).c_str(), ::toString(newPageID).c_str(), version);
}
};
#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 for default
DWALPager(int desiredPageSize, std::string filename, int64_t pageCacheSizeBytes)
: desiredPageSize(desiredPageSize), filename(filename), pHeader(nullptr), pageCacheBytes(pageCacheSizeBytes)
{
if(pageCacheBytes == 0) {
pageCacheBytes = g_network->isSimulated() ? (BUGGIFY ? FLOW_KNOBS->BUGGIFY_SIM_PAGE_CACHE_4K : FLOW_KNOBS->SIM_PAGE_CACHE_4K) : FLOW_KNOBS->PAGE_CACHE_4K;
}
commitFuture = Void();
recoverFuture = forwardError(recover(this), errorPromise);
}
void setPageSize(int size) {
logicalPageSize = size;
physicalPageSize = smallestPhysicalBlock;
while(logicalPageSize > physicalPageSize) {
physicalPageSize += smallestPhysicalBlock;
}
if(pHeader != nullptr) {
pHeader->pageSize = logicalPageSize;
}
pageCache.setSizeLimit(pageCacheBytes / physicalPageSize);
}
void updateCommittedHeader() {
memcpy(lastCommittedHeaderPage->mutate(), headerPage->begin(), smallestPhysicalBlock);
}
ACTOR static Future<Void> recover(DWALPager *self) {
ASSERT(!self->recoverFuture.isValid());
self->remapUndoFuture = Void();
int64_t flags = IAsyncFile::OPEN_UNCACHED | IAsyncFile::OPEN_READWRITE | IAsyncFile::OPEN_LOCK;
state bool 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");
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.castTo<Page>()->verifyChecksum(0)) {
TraceEvent(SevWarn, "DWALPagerRecoveringHeader").detail("Filename", self->filename);
wait(store(self->headerPage, self->readHeaderPage(self, 1)));
if(!self->headerPage.castTo<Page>()->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) {
if(r.newPageID != invalidLogicalPageID) {
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();
}
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->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();
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<IPage> newPageBuffer() override {
return Reference<IPage>(new FastAllocatedPage(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.
int getUsablePageSize() override {
return logicalPageSize - sizeof(FastAllocatedPage::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<IPage> 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());
VALGRIND_MAKE_MEM_DEFINED(page->begin(), page->size());
((Page *)page.getPtr())->updateChecksum(pageID);
// 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<IPage> page) {
return writePhysicalPage(pageID, page, true);
}
void updatePage(LogicalPageID pageID, Reference<IPage> data) override {
// Get the cache entry for this page, without counting it as a cache hit as we're replacing its contents now
PageCacheEntry &cacheEntry = pageCache.get(pageID, 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 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 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<IPage> data, Version v) override {
debug_printf("DWALPager(%s) op=writeAtomic %s @%" PRId64 "\n", filename.c_str(), toString(pageID).c_str(), v);
// This pager does not support atomic update, so it always allocates and uses a new pageID
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 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
if(remappedPages.find(pageID) != 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});
return;
}
// 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});
}
};
// 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<IPage>> readPhysicalPage(DWALPager *self, PhysicalPageID pageID, bool header = false) {
if(g_network->getCurrentTask() > TaskPriority::DiskRead) {
wait(delay(0, TaskPriority::DiskRead));
}
state Reference<IPage> page = header ? Reference<IPage>(new FastAllocatedPage(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) {
Page *p = (Page *)page.getPtr();
if(!p->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", p->calculateChecksum(pageID))
.detail("ChecksumInPage", p->getChecksum())
.error(e);
throw e;
}
}
return page;
}
static Future<Reference<IPage>> readHeaderPage(DWALPager *self, PhysicalPageID pageID) {
return readPhysicalPage(self, pageID, true);
}
// Reads the most recent version of pageID either committed or written using updatePage()
Future<Reference<IPage>> readPage(LogicalPageID pageID, bool cacheable, bool noHit = false) 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(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 = readPhysicalPage(this, (PhysicalPageID)pageID);
cacheEntry.writeFuture = Void();
}
cacheEntry.readFuture = forwardError(cacheEntry.readFuture, errorPromise);
return cacheEntry.readFuture;
}
Future<Reference<IPage>> readPageAtVersion(LogicalPageID pageID, Version v, bool cacheable, bool noHit) {
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) read %s @%" PRId64 " -> %s\n", filename.c_str(), toString(pageID).c_str(), v, toString(j->second).c_str());
pageID = j->second;
}
}
else {
debug_printf("DWALPager(%s) read %s @%" PRId64 " (not remapped)\n", filename.c_str(), toString(pageID).c_str(), v);
}
return readPage(pageID, cacheable, noHit);
}
// 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 version set as of the last commit.
Version getOldestVersion() override {
return pLastCommittedHeader->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> undoRemaps(DWALPager *self) {
state RemappedPage cutoff;
cutoff.version = self->effectiveOldestVersion();
// TODO: Use parallel reads
// TODO: One run of this actor might write to the same original page more than once, in which case just unmap the latest
loop {
if(self->remapUndoStop) {
break;
}
state Optional<RemappedPage> p = wait(self->remapQueue.pop(cutoff));
if(!p.present()) {
break;
}
debug_printf("DWALPager(%s) undoRemaps popped %s\n", self->filename.c_str(), p.get().toString().c_str());
if(p.get().newPageID == invalidLogicalPageID) {
debug_printf("DWALPager(%s) undoRemaps freeing %s\n", self->filename.c_str(), p.get().toString().c_str());
self->freePage(p.get().originalPageID, p.get().version);
}
else {
// Read the data from the page that the original was mapped to
Reference<IPage> data = wait(self->readPage(p.get().newPageID, false));
// Write the data to the original page so it can be read using its original pageID
self->updatePage(p.get().originalPageID, data);
// Remove the remap from this page, deleting the entry for the pageID if its map becomes empty
auto i = self->remappedPages.find(p.get().originalPageID);
if(i->second.size() == 1) {
self->remappedPages.erase(i);
}
else {
i->second.erase(p.get().version);
}
// Now that the remap has been undone nothing will read this page so it can be freed as of the next commit.
self->freePage(p.get().newPageID, 0);
}
}
debug_printf("DWALPager(%s) undoRemaps stopped, remapQueue size is %d\n", self->filename.c_str(), self->remapQueue.numEntries);
return Void();
}
// Flush all queues so they have no operations pending.
ACTOR static Future<Void> flushQueues(DWALPager *self) {
ASSERT(self->remapUndoFuture.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()
loop {
state bool freeBusy = wait(self->freeList.preFlush());
state bool delayedFreeBusy = wait(self->delayedFreeList.preFlush());
// 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) {
break;
}
}
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->remapUndoStop = true;
wait(self->remapUndoFuture);
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));
}
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));
}
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->remapUndoStop = false;
self->remapUndoFuture = undoRemaps(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->remapUndoFuture.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) {
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() override {
ASSERT(recoverFuture.isReady());
int64_t free;
int64_t total;
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,
// 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 most of the time.
int64_t reusable = (freeList.numEntries + delayedFreeList.numEntries) * physicalPageSize;
return StorageBytes(free, total, pagerSize, free + reusable);
}
ACTOR static Future<Void> getUserPageCount_cleanup(DWALPager *self) {
// Wait for the remap eraser to finish all of its work (not triggering stop)
wait(self->remapUndoFuture);
// 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() 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<IPage>> 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<IPage> headerPage;
Header *pHeader;
int desiredPageSize;
Reference<IPage> lastCommittedHeaderPage;
Header *pLastCommittedHeader;
std::string filename;
typedef ObjectCache<LogicalPageID, PageCacheEntry> PageCacheT;
PageCacheT pageCache;
Promise<Void> closedPromise;
Promise<Void> errorPromise;
Future<Void> commitFuture;
SignalableActorCollection operations;
Future<Void> recoverFuture;
Future<Void> remapUndoFuture;
bool remapUndoStop;
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;
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
std::unordered_map<LogicalPageID, std::map<Version, LogicalPageID>> 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) {
}
virtual ~DWALPagerSnapshot() {
}
Future<Reference<const IPage>> getPhysicalPage(LogicalPageID pageID, bool cacheable, bool noHit) override {
if(expired.isError()) {
throw expired.getError();
}
return map(pager->readPageAtVersion(pageID, version, cacheable, noHit), [=](Reference<IPage> p) {
return Reference<const IPage>(p);
});
}
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,
Reference<DWALPagerSnapshot>(new 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 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> BTreePageID;
std::string toString(BTreePageID 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 = {}, uint32_t chunkTotal = 0, uint32_t chunkStart = 0)
: key(key), version(ver), value(value), chunk({chunkTotal, chunkStart})
{
}
RedwoodRecordRef(Arena &arena, const RedwoodRecordRef &toCopy)
: key(arena, toCopy.key), version(toCopy.version), chunk(toCopy.chunk)
{
if(toCopy.value.present()) {
value = ValueRef(arena, toCopy.value.get());
}
}
RedwoodRecordRef(KeyRef key, Optional<ValueRef> value, const byte intFields[14])
: key(key), value(value)
{
deserializeIntFields(intFields);
}
// 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 BTreePageID getChildPage() const {
ASSERT(value.present());
return BTreePageID((LogicalPageID *)value.get().begin(), value.get().size() / sizeof(LogicalPageID));
}
inline void setChildPage(BTreePageID id) {
value = ValueRef((const uint8_t *)id.begin(), id.size() * sizeof(LogicalPageID));
}
inline void setChildPage(Arena &arena, BTreePageID id) {
value = ValueRef(arena, (const uint8_t *)id.begin(), id.size() * sizeof(LogicalPageID));
}
inline RedwoodRecordRef withPageID(BTreePageID id) const {
return RedwoodRecordRef(key, version, ValueRef((const uint8_t *)id.begin(), id.size() * sizeof(LogicalPageID)), chunk.total, chunk.start);
}
inline RedwoodRecordRef withoutValue() const {
return RedwoodRecordRef(key, version, {}, chunk.total, chunk.start);
}
// Returns how many bytes are in common between the integer fields of *this and other, assuming that
// all values are BigEndian, version is 64 bits, chunk total is 24 bits, and chunk start is 24 bits
int getCommonIntFieldPrefix(const RedwoodRecordRef &other) const {
if(version != other.version) {
return clzll(version ^ other.version) >> 3;
}
if(chunk.total != other.chunk.total) {
// the -1 is because we are only considering the lower 3 bytes
return 8 + (clz(chunk.total ^ other.chunk.total) >> 3) - 1;
}
if(chunk.start != other.chunk.start) {
// the -1 is because we are only considering the lower 3 bytes
return 11 + (clz(chunk.start ^ other.chunk.start) >> 3) - 1;
}
return 14;
}
// Truncate (key, version, chunk.total, chunk.start) tuple to len bytes.
void truncate(int len) {
if(len <= key.size()) {
key = key.substr(0, len);
version = 0;
chunk.total = 0;
chunk.start = 0;
}
else {
byte fields[intFieldArraySize];
serializeIntFields(fields);
int end = len - key.size();
for(int i = intFieldArraySize - 1; i >= end; --i) {
fields[i] = 0;
}
}
}
// Find the common prefix between two records, assuming that the first
// skip bytes are the same.
inline int getCommonPrefixLen(const RedwoodRecordRef &other, int skip) const {
int skipStart = std::min(skip, key.size());
int common = skipStart + commonPrefixLength(key.begin() + skipStart, other.key.begin() + skipStart, std::min(other.key.size(), key.size()) - skipStart);
if(common == key.size() && key.size() == other.key.size()) {
common += getCommonIntFieldPrefix(other);
}
return common;
}
static const int intFieldArraySize = 14;
// Write big endian values of version (64 bits), total (24 bits), and start (24 bits) fields
// to an array of 14 bytes
void serializeIntFields(byte *dst) const {
*(uint32_t *)(dst + 10) = bigEndian32(chunk.start);
*(uint32_t *)(dst + 7) = bigEndian32(chunk.total);
*(uint64_t *)dst = bigEndian64(version);
}
// Initialize int fields from the array format that serializeIntFields produces
void deserializeIntFields(const byte *src) {
version = bigEndian64(*(uint64_t *)src);
chunk.total = bigEndian32(*(uint32_t *)(src + 7)) & 0xffffff;
chunk.start = bigEndian32(*(uint32_t *)(src + 10)) & 0xffffff;
}
// TODO: Use SplitStringRef (unless it ends up being slower)
KeyRef key;
Optional<ValueRef> value;
Version version;
struct {
uint32_t total;
// TODO: Change start to chunk number?
uint32_t start;
} chunk;
int expectedSize() const {
return key.expectedSize() + value.expectedSize();
}
bool isMultiPart() const {
return chunk.total != 0;
}
// Generate a kv shard from a complete kv
RedwoodRecordRef split(int start, int len) {
ASSERT(!isMultiPart());
return RedwoodRecordRef(key, version, value.get().substr(start, len), value.get().size(), start);
}
class Writer {
public:
Writer(byte *ptr) : wptr(ptr) {}
byte *wptr;
template<typename T> void write(const T &in) {
*(T *)wptr = in;
wptr += sizeof(T);
}
// Write a big endian 1 or 2 byte integer using the high bit of the first byte as an "extension" bit.
// Values > 15 bits in length are not valid input but this is not checked for.
void writeVarInt(int x) {
if(x >= 128) {
*wptr++ = (uint8_t)( (x >> 8) | 0x80 );
}
*wptr++ = (uint8_t)x;
}
void writeString(StringRef s) {
memcpy(wptr, s.begin(), s.size());
wptr += s.size();
}
};
class Reader {
public:
Reader(const void *ptr) : rptr((const byte *)ptr) {}
const byte *rptr;
template<typename T> T read() {
T r = *(const T *)rptr;
rptr += sizeof(T);
return r;
}
// Read a big endian 1 or 2 byte integer using the high bit of the first byte as an "extension" bit.
int readVarInt() {
int x = *rptr++;
// If the high bit is set
if(x & 0x80) {
// Clear the high bit
x &= 0x7f;
// Shift low byte left
x <<= 8;
// Read the new low byte and OR it in
x |= *rptr++;
}
return x;
}
StringRef readString(int len) {
StringRef s(rptr, len);
rptr += len;
return s;
}
const byte * readBytes(int len) {
const byte *b = rptr;
rptr += len;
return b;
}
};
#pragma pack(push,1)
struct Delta {
// Serialized Format
//
// 1 byte for Flags + a 4 bit length
// borrow source is prev ancestor - 0 or 1
// has_key_suffix
// has_value
// has_version
// other_fields suffix len - 4 bits
//
// If has value and value is not 4 bytes
// 1 byte value length
//
// 1 or 2 bytes for Prefix Borrow Length (hi bit indicates presence of second byte)
//
// IF has_key_suffix is set
// 1 or 2 bytes for Key Suffix Length
//
// Key suffix bytes
// Meta suffix bytes
// Value bytes
//
// For a series of RedwoodRecordRef's containing shards of the same KV pair where the key size is < 104 bytes,
// the overhead per middle chunk is 7 bytes:
// 4 bytes of child pointers in the DeltaTree Node
// 1 flag byte
// 1 prefix borrow length byte
// 1 meta suffix byte describing chunk start position
enum EFlags {
PREFIX_SOURCE = 0x80,
HAS_KEY_SUFFIX = 0x40,
HAS_VALUE = 0x20,
HAS_VERSION = 0x10,
INT_FIELD_SUFFIX_BITS = 0x0f
};
uint8_t flags;
inline byte * data() {
return (byte *)(this + 1);
}
inline const byte * data() const {
return (const byte *)(this + 1);
}
void setPrefixSource(bool val) {
if(val) {
flags |= PREFIX_SOURCE;
}
else {
flags &= ~PREFIX_SOURCE;
}
}
bool getPrefixSource() const {
return flags & PREFIX_SOURCE;
}
RedwoodRecordRef apply(const RedwoodRecordRef &base, Arena &arena) const {
Reader r(data());
int intFieldSuffixLen = flags & INT_FIELD_SUFFIX_BITS;
int prefixLen = r.readVarInt();
int valueLen = (flags & HAS_VALUE) ? r.read<uint8_t>() : 0;
StringRef k;
// Separate the borrowed key string byte count from the borrowed int field byte count
int keyPrefixLen = std::min(prefixLen, base.key.size());
int intFieldPrefixLen = prefixLen - keyPrefixLen;
int keySuffixLen = (flags & HAS_KEY_SUFFIX) ? r.readVarInt() : 0;
// If there is a key suffix, reconstitute the complete key into a contiguous string
if(keySuffixLen > 0) {
k = makeString(keyPrefixLen + keySuffixLen, arena);
memcpy(mutateString(k), base.key.begin(), keyPrefixLen);
memcpy(mutateString(k) + keyPrefixLen, r.readString(keySuffixLen).begin(), keySuffixLen);
}
else {
k = base.key.substr(0, keyPrefixLen);
}
// Now decode the integer fields
const byte *intFieldSuffix = r.readBytes(intFieldSuffixLen);
// Create big endian array in which to reassemble the integer fields from prefix and suffix bytes
byte intFields[intFieldArraySize];
// If borrowing any bytes, get the source's integer field array
if(intFieldPrefixLen > 0) {
base.serializeIntFields(intFields);
}
else {
memset(intFields, 0, intFieldArraySize);
}
// Version offset is used to skip the version bytes in the int field array when version is missing (aka 0)
int versionOffset = ( (intFieldPrefixLen == 0) && (~flags & HAS_VERSION) ) ? 8 : 0;
// If there are suffix bytes, copy those into place after the prefix
if(intFieldSuffixLen > 0) {
memcpy(intFields + versionOffset + intFieldPrefixLen, intFieldSuffix, intFieldSuffixLen);
}
// Zero out any remaining bytes if the array was initialized from base
if(intFieldPrefixLen > 0) {
for(int i = versionOffset + intFieldPrefixLen + intFieldSuffixLen; i < intFieldArraySize; ++i) {
intFields[i] = 0;
}
}
return RedwoodRecordRef(k, flags & HAS_VALUE ? r.readString(valueLen) : Optional<ValueRef>(), intFields);
}
int size() const {
Reader r(data());
int intFieldSuffixLen = flags & INT_FIELD_SUFFIX_BITS;
r.readVarInt(); // prefixlen
int valueLen = (flags & HAS_VALUE) ? r.read<uint8_t>() : 0;
int keySuffixLen = (flags & HAS_KEY_SUFFIX) ? r.readVarInt() : 0;
return sizeof(Delta) + r.rptr - data() + intFieldSuffixLen + valueLen + keySuffixLen;
}
// Delta can't be determined without the RedwoodRecordRef upon which the Delta is based.
std::string toString() const {
Reader r(data());
std::string flagString = " ";
if(flags & PREFIX_SOURCE) flagString += "prefixSource ";
if(flags & HAS_KEY_SUFFIX) flagString += "keySuffix ";
if(flags & HAS_VERSION) flagString += "Version ";
if(flags & HAS_VALUE) flagString += "Value ";
int intFieldSuffixLen = flags & INT_FIELD_SUFFIX_BITS;
int prefixLen = r.readVarInt();
int valueLen = (flags & HAS_VALUE) ? r.read<uint8_t>() : 0;
int keySuffixLen = (flags & HAS_KEY_SUFFIX) ? r.readVarInt() : 0;
return format("len: %d flags: %s prefixLen: %d keySuffixLen: %d intFieldSuffix: %d valueLen %d raw: %s",
size(), flagString.c_str(), prefixLen, keySuffixLen, intFieldSuffixLen, 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 {
Reader r(data());
// Skip prefix length
r.readVarInt();
// Get value length
int valueLen = (flags & HAS_VALUE) ? r.read<uint8_t>() : 0;
// Skip key suffix length and bytes if exists
if(flags & HAS_KEY_SUFFIX) {
r.readString(r.readVarInt());
}
// Skip int field suffix if present
r.readBytes(flags & INT_FIELD_SUFFIX_BITS);
return RedwoodRecordRef(StringRef(), 0, (flags & HAS_VALUE ? r.readString(valueLen) : Optional<ValueRef>()) );
}
};
#pragma pack(pop)
// Compares and orders by key, version, chunk.start, chunk.total.
// Value is not considered, as it is does not make sense for a container
// to have two records which differ only in value.
int compare(const RedwoodRecordRef &rhs) const {
int cmp = key.compare(rhs.key);
if(cmp == 0) {
cmp = version - rhs.version;
if(cmp == 0) {
// It is assumed that in any data set there will never be more than one
// unique chunk total size for the same key and version, so sort by start, total
// Chunked (represented by chunk.total > 0) sorts higher than whole
cmp = chunk.start - rhs.chunk.start;
if(cmp == 0) {
cmp = chunk.total - rhs.chunk.total;
}
}
}
return cmp;
}
// Compares key fields and value for equality
bool identical(const RedwoodRecordRef &rhs) const {
return compare(rhs) == 0 && value == rhs.value;
}
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;
}
int deltaSize(const RedwoodRecordRef &base, bool worstCase = true) const {
int size = sizeof(Delta);
if(value.present()) {
size += value.get().size();
++size;
}
int prefixLen = getCommonPrefixLen(base, 0);
size += (worstCase || prefixLen >= 128) ? 2 : 1;
int intFieldPrefixLen;
// Currently using a worst-guess guess where int fields in suffix are stored in their entirety if nonzero.
if(prefixLen < key.size()) {
int keySuffixLen = key.size() - prefixLen;
size += (worstCase || keySuffixLen >= 128) ? 2 : 1;
size += keySuffixLen;
intFieldPrefixLen = 0;
}
else {
intFieldPrefixLen = prefixLen - key.size();
if(worstCase) {
size += 2;
}
}
if(version == 0 && chunk.total == 0 && chunk.start == 0) {
// No int field suffix needed
}
else {
byte fields[intFieldArraySize];
serializeIntFields(fields);
const byte *end = fields + intFieldArraySize - 1;
int trailingNulls = 0;
while(*end-- == 0) {
++trailingNulls;
}
size += std::max(0, intFieldArraySize - intFieldPrefixLen - trailingNulls);
if(intFieldPrefixLen == 0 && version == 0) {
size -= 8;
}
}
return size;
}
// commonPrefix between *this and base can be passed if known
int writeDelta(Delta &d, const RedwoodRecordRef &base, int commonPrefix = -1) const {
d.flags = version == 0 ? 0 : Delta::HAS_VERSION;
if(commonPrefix < 0) {
commonPrefix = getCommonPrefixLen(base, 0);
}
Writer w(d.data());
// prefixLen
w.writeVarInt(commonPrefix);
// valueLen
if(value.present()) {
d.flags |= Delta::HAS_VALUE;
w.write<uint8_t>(value.get().size());
}
// keySuffixLen
if(key.size() > commonPrefix) {
d.flags |= Delta::HAS_KEY_SUFFIX;
StringRef keySuffix = key.substr(commonPrefix);
w.writeVarInt(keySuffix.size());
// keySuffix
w.writeString(keySuffix);
}
// This is a common case, where no int suffix is needed
if(version == 0 && chunk.total == 0 && chunk.start == 0) {
// The suffixLen bits in flags are already zero, so nothing to do here.
}
else {
byte fields[intFieldArraySize];
serializeIntFields(fields);
// Find the position of the first null byte from the right
// This for loop has no endPos > 0 check because it is known that the array contains non-null bytes
int endPos;
for(endPos = intFieldArraySize; fields[endPos - 1] == 0; --endPos);
// Start copying after any prefix bytes that matched the int fields of the base
int intFieldPrefixLen = std::max(0, commonPrefix - key.size());
int startPos = intFieldPrefixLen + (intFieldPrefixLen == 0 && version == 0 ? 8 : 0);
int suffixLen = std::max(0, endPos - startPos);
if(suffixLen > 0) {
w.writeString(StringRef(fields + startPos, suffixLen));
d.flags |= suffixLen;
}
}
if(value.present()) {
w.writeString(value.get());
}
return w.wptr - d.data() + sizeof(Delta);
}
template<typename StringRefT>
static std::string kvformat(StringRefT 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(int hexLimit = 15) const {
std::string r;
r += format("'%s'@%" PRId64, kvformat(key, hexLimit).c_str(), version);
r += format("[%u/%u]->", chunk.start, chunk.total);
if(value.present()) {
// Assume that values the size of a page ID are page IDs. It's not perfect but it's just for debugging.
if(value.get().size() == sizeof(LogicalPageID)) {
r += format("[%s]", ::toString(getChildPage()).c_str());
}
else {
r += format("'%s'", kvformat(value.get(), hexLimit).c_str());
}
}
else {
r += "null";
}
return r;
}
};
struct BTreePage {
typedef DeltaTree<RedwoodRecordRef> BinaryTree;
typedef DeltaTree<RedwoodRecordRef, RedwoodRecordRef::DeltaValueOnly> ValueTree;
#pragma pack(push,1)
struct {
uint8_t height;
uint16_t itemCount;
uint32_t kvBytes;
};
#pragma pack(pop)
int size() const {
const BinaryTree *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);
}
std::string toString(bool write, BTreePageID 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)itemCount, (int)kvBytes,
lowerBound->toString().c_str(), upperBound->toString().c_str());
try {
if(itemCount > 0) {
// This doesn't use the cached reader for the page but it is only for debugging purposes
BinaryTree::Reader reader(&tree(), lowerBound, upperBound);
BinaryTree::Cursor c = reader.getCursor();
c.moveFirst();
ASSERT(c.valid());
bool anyOutOfRange = false;
do {
r += " ";
r += c.get().toString();
bool tooLow = c.get().key < lowerBound->key;
bool tooHigh = c.get().key > upperBound->key;
if(tooLow || tooHigh) {
anyOutOfRange = true;
if(tooLow) {
r += " (too low)";
}
if(tooHigh) {
r += " (too high)";
}
}
r += "\n";
} while(c.moveNext());
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;
}
return r;
}
};
static void makeEmptyRoot(Reference<IPage> page) {
BTreePage *btpage = (BTreePage *)page->begin();
btpage->height = 1;
btpage->kvBytes = 0;
btpage->itemCount = 0;
btpage->tree().build(nullptr, nullptr, nullptr, nullptr);
}
BTreePage::BinaryTree::Reader * getReader(Reference<const IPage> page) {
return (BTreePage::BinaryTree::Reader *)page->userData;
}
struct BoundaryRefAndPage {
Standalone<RedwoodRecordRef> lowerBound;
Reference<IPage> firstPage;
std::vector<Reference<IPage>> 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 : 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 LazyDeleteQueueEntry {
Version version;
Standalone<BTreePageID> pageID;
bool operator< (const LazyDeleteQueueEntry &rhs) const {
return version < rhs.version;
}
int readFromBytes(const uint8_t *src) {
version = *(Version *)src;
src += sizeof(Version);
int count = *src++;
pageID = BTreePageID((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<LazyDeleteQueueEntry> LazyDeleteQueueT;
#pragma pack(push, 1)
struct MetaKey {
static constexpr int FORMAT_VERSION = 2;
// This serves as the format version for the entire tree, individual pages will not be versioned
uint16_t formatVersion;
uint8_t height;
LazyDeleteQueueT::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)
struct Counts {
Counts() {
memset(this, 0, sizeof(Counts));
startTime = g_network ? now() : 0;
}
void clear() {
*this = Counts();
}
int64_t pageReads;
int64_t extPageReads;
int64_t pagePreloads;
int64_t extPagePreloads;
int64_t setBytes;
int64_t pageWrites;
int64_t extPageWrites;
int64_t sets;
int64_t clears;
int64_t commits;
int64_t gets;
int64_t getRanges;
int64_t commitToPage;
int64_t commitToPageStart;
double startTime;
std::string toString(bool clearAfter = false) {
const char *labels[] = {"set", "clear", "get", "getRange", "commit", "pageReads", "extPageRead", "pagePreloads", "extPagePreloads", "pageWrite", "extPageWrite", "commitPage", "commitPageStart"};
const int64_t values[] = {sets, clears, gets, getRanges, commits, pageReads, extPageReads, pagePreloads, extPagePreloads, pageWrites, extPageWrites, commitToPage, commitToPageStart};
double elapsed = now() - startTime;
std::string s;
for(int i = 0; i < sizeof(values) / sizeof(int64_t); ++i) {
s += format("%s=%" PRId64 " (%d/s) ", labels[i], values[i], int(values[i] / elapsed));
}
if(clearAfter) {
clear();
}
return s;
}
};
// Using a static for metrics because a single process shouldn't normally have multiple storage engines
static Counts counts;
// 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() {
return m_pager->getError();
}
Future<Void> onClosed() {
return m_pager->onClosed();
}
void close_impl(bool dispose) {
auto *pager = m_pager;
delete this;
if(dispose)
pager->dispose();
else
pager->close();
}
void dispose() {
return close_impl(true);
}
void close() {
return close_impl(false);
}
KeyValueStoreType getType() NOT_IMPLEMENTED
bool supportsMutation(int op) NOT_IMPLEMENTED
StorageBytes getStorageBytes() {
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) {
++counts.sets;
SingleKeyMutationsByVersion &changes = insertMutationBoundary(keyValue.key)->second.startKeyMutations;
if(singleVersion) {
if(changes.empty()) {
changes[0] = SingleKeyMutation(keyValue.value);
}
else {
changes.begin()->second = SingleKeyMutation(keyValue.value);
}
}
else {
// Add the set if the changes set is empty or the last entry isn't a set to exactly the same value
if(changes.empty() || !changes.rbegin()->second.equalToSet(keyValue.value)) {
changes[m_writeVersion] = SingleKeyMutation(keyValue.value);
}
}
}
void clear(KeyRangeRef range) {
++counts.clears;
MutationBufferT::iterator iBegin = insertMutationBoundary(range.begin);
MutationBufferT::iterator iEnd = insertMutationBoundary(range.end);
// In single version mode, clear all pending updates in the affected range
if(singleVersion) {
RangeMutation &range = iBegin->second;
range.startKeyMutations.clear();
range.startKeyMutations[0] = SingleKeyMutation();
range.rangeClearVersion = 0;
++iBegin;
m_pBuffer->erase(iBegin, iEnd);
}
else {
// For each boundary in the cleared range
while(iBegin != iEnd) {
RangeMutation &range = iBegin->second;
// Set the rangeClearedVersion if not set
if(!range.rangeClearVersion.present())
range.rangeClearVersion = m_writeVersion;
// Add a clear to the startKeyMutations map if it's empty or the last item is not a clear
if(range.startKeyMutations.empty() || !range.startKeyMutations.rbegin()->second.isClear())
range.startKeyMutations[m_writeVersion] = SingleKeyMutation();
++iBegin;
}
}
}
void mutate(int op, StringRef param1, StringRef param2) NOT_IMPLEMENTED
void setOldestVersion(Version v) {
m_newOldestVersion = v;
}
Version getOldestVersion() {
return m_pager->getOldestVersion();
}
Version getLatestVersion() {
if(m_writeVersion != invalidVersion)
return m_writeVersion;
return m_pager->getLatestVersion();
}
Version getWriteVersion() {
return m_writeVersion;
}
Version getLastCommittedVersion() {
return m_lastCommittedVersion;
}
VersionedBTree(IPager2 *pager, std::string name, bool singleVersion = false)
: m_pager(pager),
m_writeVersion(invalidVersion),
m_lastCommittedVersion(invalidVersion),
m_pBuffer(nullptr),
m_name(name),
singleVersion(singleVersion)
{
m_init = init_impl(this);
m_latestCommit = m_init;
}
ACTOR static Future<int> incrementalSubtreeClear(VersionedBTree *self, bool *pStop = nullptr, unsigned int minPages = 0, int maxPages = std::numeric_limits<int>::max()) {
// 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 {
// take a page from front of queue
state Optional<LazyDeleteQueueEntry> q = wait(self->m_lazyDeleteQueue.pop());
debug_printf("LazyDelete: popped %s\n", toString(q).c_str());
if(!q.present()) {
break;
}
// Read the page without caching
Reference<const IPage> p = wait(self->readPage(snapshot, q.get().pageID, nullptr, nullptr, true));
const BTreePage &btPage = *(BTreePage *)p->begin();
// 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::Reader reader(&btPage.valueTree(), &dbBegin, &dbEnd);
auto c = reader.getCursor();
ASSERT(c.moveFirst());
Version v = q.get().version;
while(1) {
if(c.get().value.present()) {
BTreePageID btChildPageID = c.get().getChildPage();
// If this page is height 2, then the children are leaves so free
if(btPage.height == 2) {
debug_printf("LazyDelete: freeing child %s\n", toString(btChildPageID).c_str());
self->freeBtreePage(btChildPageID, v);
freedPages += btChildPageID.size();
}
else {
// Otherwise, queue them for lazy delete.
debug_printf("LazyDelete: queuing child %s\n", toString(btChildPageID).c_str());
self->m_lazyDeleteQueue.pushFront(LazyDeleteQueueEntry{v, btChildPageID});
}
}
if(!c.moveNext()) {
break;
}
}
// Free the page, now that its children have either been freed or queued
debug_printf("LazyDelete: freeing queue entry %s\n", toString(q.get().pageID).c_str());
self->freeBtreePage(q.get().pageID, v);
freedPages += q.get().pageID.size();
// If stop is set and we've freed the minimum number of pages required, or the maximum is exceeded, return.
if((freedPages >= minPages && pStop != nullptr && *pStop) || freedPages >= maxPages) {
break;
}
}
debug_printf("LazyDelete: freed %d pages, %s has %" PRId64 " entries\n", freedPages, self->m_lazyDeleteQueue.name.c_str(), self->m_lazyDeleteQueue.numEntries);
return freedPages;
}
ACTOR static Future<Void> init_impl(VersionedBTree *self) {
wait(self->m_pager->init());
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());
BTreePageID 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<IPage> 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_lazyDeleteQueue.create(self->m_pager, newQueuePage, "LazyDeleteQueue");
self->m_header.lazyDeleteQueue = self->m_lazyDeleteQueue.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_lazyDeleteQueue.recover(self->m_pager, self->m_header.lazyDeleteQueue, "LazyDeleteQueueRecovered");
}
debug_printf("Recovered btree at version %" PRId64 ": %s\n", latest, self->m_header.toString().c_str());
self->m_maxPartSize = std::min(255, self->m_pager->getUsablePageSize() / 5);
self->m_lastCommittedVersion = latest;
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) {
// Only committed versions can be read.
Version recordVersion = singleVersion ? 0 : v;
ASSERT(v <= m_lastCommittedVersion);
if(singleVersion) {
ASSERT(v == m_lastCommittedVersion);
}
Reference<IPagerSnapshot> snapshot = m_pager->getReadSnapshot(v);
// Snapshot will continue to hold the metakey value memory
KeyRef m = snapshot->getMetaKey();
return Reference<IStoreCursor>(new Cursor(snapshot, ((MetaKey *)m.begin())->root.get(), recordVersion));
}
// Must be nondecreasing
void setWriteVersion(Version v) {
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];
// 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.
(*m_pBuffer)[dbBegin.key] = RangeMutation();
// 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.
(*m_pBuffer)[dbEnd.key].startKeyMutations[0] = SingleKeyMutation();
}
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() {
if(m_pBuffer == nullptr)
return m_latestCommit;
return commit_impl(this);
}
ACTOR static Future<Void> destroyAndCheckSanity_impl(VersionedBTree *self) {
ASSERT(g_network->isSimulated());
debug_printf("Clearing tree.\n");
self->setWriteVersion(self->getLatestVersion() + 1);
self->clear(KeyRangeRef(dbBegin.key, dbEnd.key));
loop {
state int freedPages = wait(self->incrementalSubtreeClear(self));
wait(self->commit());
// Keep looping until the last commit doesn't do anything at all
if(self->m_lazyDeleteQueue.numEntries == 0 && freedPages == 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.
LazyDeleteQueueT::QueueState s = self->m_lazyDeleteQueue.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> destroyAndCheckSanity() {
return destroyAndCheckSanity_impl(this);
}
bool isSingleVersion() const {
return singleVersion;
}
private:
struct VersionAndChildrenRef {
VersionAndChildrenRef(Version v, VectorRef<RedwoodRecordRef> children, RedwoodRecordRef upperBound)
: version(v), children(children), upperBound(upperBound) {
}
VersionAndChildrenRef(Arena &arena, const VersionAndChildrenRef &toCopy)
: version(toCopy.version), children(arena, toCopy.children), upperBound(arena, toCopy.upperBound) {
}
int expectedSize() const {
return children.expectedSize() + upperBound.expectedSize();
}
std::string toString() const {
return format("{version=%" PRId64 " children=%s upperbound=%s}", version, ::toString(children).c_str(), upperBound.toString().c_str());
}
Version version;
VectorRef<RedwoodRecordRef> children;
RedwoodRecordRef upperBound;
};
typedef VectorRef<VersionAndChildrenRef> VersionedChildrenT;
// Utility class for building a vector of internal page entries.
// Entries must be added in version order. Modified will be set to true
// if any entries differ from the original ones. Additional entries will be
// added when necessary to reconcile differences between the upper and lower
// boundaries of consecutive entries.
struct InternalPageBuilder {
// Cursor must be at first entry in page
InternalPageBuilder(const BTreePage::BinaryTree::Cursor &c)
: cursor(c), modified(false), childPageCount(0)
{
}
private:
// This must be called internally, on records whose arena has already been added to the entries arena
inline void addEntry(const RedwoodRecordRef &rec) {
if(rec.value.present()) {
++childPageCount;
}
// If no modification detected yet then check that this record is identical to the next
// record from the original page which is at the current cursor position.
if(!modified) {
if(cursor.valid()) {
if(!rec.identical(cursor.get())) {
debug_printf("InternalPageBuilder: Found internal page difference. new: %s old: %s\n", rec.toString().c_str(), cursor.get().toString().c_str());
modified = true;
}
else {
cursor.moveNext();
}
}
else {
debug_printf("InternalPageBuilder: Found internal page difference. new: %s old: <end>\n", rec.toString().c_str());
modified = true;
}
}
entries.push_back(entries.arena(), rec);
}
public:
// Add the child entries from newSet into entries
void addEntries(VersionAndChildrenRef newSet) {
// If there are already entries, the last one links to a child page, and its upper bound is not the same
// as the first lowerBound in newSet (or newSet is empty, as the next newSet is necessarily greater)
// then add the upper bound of the previous set as a value-less record so that on future reads
// the previous child page can be decoded correctly.
if(!entries.empty() && entries.back().value.present()
&& (newSet.children.empty() || newSet.children.front() != lastUpperBound))
{
debug_printf("InternalPageBuilder: Added placeholder %s\n", lastUpperBound.withoutValue().toString().c_str());
addEntry(lastUpperBound.withoutValue());
}
for(auto &child : newSet.children) {
debug_printf("InternalPageBuilder: Adding child entry %s\n", child.toString().c_str());
addEntry(child);
}
lastUpperBound = newSet.upperBound;
debug_printf("InternalPageBuilder: New upper bound: %s\n", lastUpperBound.toString().c_str());
}
// Finish comparison to existing data if necesary.
// Handle possible page upper bound changes.
// If modified is set (see below) and our rightmost entry has a child page and its upper bound
// (currently in lastUpperBound) does not match the new desired page upper bound, passed as newUpperBound,
// then write lastUpperBound with no value to allow correct decoding of the rightmost entry.
// This is only done if modified is set to avoid rewriting this page for this purpose only.
//
// After this call, lastUpperBound is internal page's upper bound.
void finalize(const RedwoodRecordRef &upperBound, const RedwoodRecordRef &decodeUpperBound) {
debug_printf("InternalPageBuilder::end modified=%d upperBound=%s decodeUpperBound=%s lastUpperBound=%s\n", modified, upperBound.toString().c_str(), decodeUpperBound.toString().c_str(), lastUpperBound.toString().c_str());
modified = modified || cursor.valid();
debug_printf("InternalPageBuilder::end modified=%d after cursor check\n", modified);
// If there are boundary key entries and the last one has a child page then the
// upper bound for this internal page must match the required upper bound for
// the last child entry.
if(!entries.empty() && entries.back().value.present()) {
debug_printf("InternalPageBuilder::end last entry is not null\n");
// If the page contents were not modified so far and the upper bound required
// for the last child page (lastUpperBound) does not match what the page
// was encoded with then the page must be modified.
if(!modified && lastUpperBound != decodeUpperBound) {
debug_printf("InternalPageBuilder::end modified set true because lastUpperBound does not match decodeUpperBound\n");
modified = true;
}
if(modified && lastUpperBound != upperBound) {
debug_printf("InternalPageBuilder::end Modified is true but lastUpperBound does not match upperBound so adding placeholder\n");
addEntry(lastUpperBound.withoutValue());
lastUpperBound = upperBound;
}
}
debug_printf("InternalPageBuilder::end exit. modified=%d upperBound=%s decodeUpperBound=%s lastUpperBound=%s\n", modified, upperBound.toString().c_str(), decodeUpperBound.toString().c_str(), lastUpperBound.toString().c_str());
}
BTreePage::BinaryTree::Cursor cursor;
Standalone<VectorRef<RedwoodRecordRef>> entries;
RedwoodRecordRef lastUpperBound;
bool modified;
int childPageCount;
};
// 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());
}
};
// Represents mutations on a single key and a possible clear to a range that begins
// immediately after that key
typedef std::map<Version, SingleKeyMutation> SingleKeyMutationsByVersion;
struct RangeMutation {
// Mutations for exactly the start key
SingleKeyMutationsByVersion startKeyMutations;
// A clear range version, if cleared, for the range starting immediately AFTER the start key
Optional<Version> rangeClearVersion;
bool keyCleared() const {
return startKeyMutations.size() == 1 && startKeyMutations.begin()->second.isClear();
}
bool keyChanged() const {
return !startKeyMutations.empty();
}
bool rangeCleared() const {
return rangeClearVersion.present();
}
// Returns true if this RangeMutation doesn't actually mutate anything
bool noChanges() const {
return !rangeClearVersion.present() && startKeyMutations.empty();
}
std::string toString() const {
std::string result;
result.append("rangeClearVersion: ");
if(rangeClearVersion.present())
result.append(format("%" PRId64 "", rangeClearVersion.get()));
else
result.append("<not present>");
result.append(" startKeyMutations: ");
for(SingleKeyMutationsByVersion::value_type const &m : startKeyMutations)
result.append(format("[%" PRId64 " => %s] ", m.first, m.second.toString().c_str()));
return result;
}
};
typedef std::map<Key, RangeMutation> MutationBufferT;
/* 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;
MutationBufferT *m_pBuffer;
std::map<Version, MutationBufferT> m_mutationBuffers;
Version m_writeVersion;
Version m_lastCommittedVersion;
Version m_newOldestVersion;
Future<Void> m_latestCommit;
Future<Void> m_init;
std::string m_name;
bool singleVersion;
// MetaKey changes size so allocate space for it to expand into
union {
uint8_t headerSpace[sizeof(MetaKey) + sizeof(LogicalPageID) * 20];
MetaKey m_header;
};
LazyDeleteQueueT m_lazyDeleteQueue;
int m_maxPartSize;
// Find or create a mutation buffer boundary for bound and return an iterator to it
MutationBufferT::iterator insertMutationBoundary(Key boundary) {
ASSERT(m_pBuffer != nullptr);
// Find the first split point in buffer that is >= key
MutationBufferT::iterator ib = m_pBuffer->lower_bound(boundary);
// Since the initial state of the mutation buffer contains the range '' through
// the maximum possible key, our search had to have found something.
ASSERT(ib != m_pBuffer->end());
// If we found the boundary we are looking for, return its iterator
if(ib->first == boundary)
return ib;
// ib is our insert hint. Insert the new boundary and set ib to its entry
ib = m_pBuffer->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.
MutationBufferT::iterator iPrevious = ib;
--iPrevious;
if(iPrevious->second.rangeClearVersion.present()) {
ib->second.rangeClearVersion = iPrevious->second.rangeClearVersion;
ib->second.startKeyMutations[iPrevious->second.rangeClearVersion.get()] = SingleKeyMutation();
}
return ib;
}
// Writes entries to 1 or more pages and return a vector of boundary keys with their IPage(s)
ACTOR static Future<Standalone<VectorRef<RedwoodRecordRef>>> writePages(VersionedBTree *self, bool minimalBoundaries, const RedwoodRecordRef *lowerBound, const RedwoodRecordRef *upperBound, VectorRef<RedwoodRecordRef> entries, int height, Version v, BTreePageID previousID) {
ASSERT(entries.size() > 0);
state Standalone<VectorRef<RedwoodRecordRef>> records;
// This is how much space for the binary tree exists in the page, after the header
state int blockSize = self->m_pager->getUsablePageSize();
state int pageSize = blockSize - sizeof(BTreePage);
state int blockCount = 1;
state int kvBytes = 0;
state int compressedBytes = BTreePage::BinaryTree::GetTreeOverhead();
state int start = 0;
state int i = 0;
state bool end;
// For leaf level where minimal boundaries are used require at least 1 entry, otherwise require 4 to enforce a minimum branching factor
state int minimumEntries = minimalBoundaries ? 1 : 4;
// Lower bound of the page being added to
state RedwoodRecordRef pageLowerBound = lowerBound->withoutValue();
state RedwoodRecordRef pageUpperBound;
while(i <= entries.size()) {
end = i == entries.size();
bool flush = end;
// If not the end, add i to the page if necessary
if(end) {
pageUpperBound = upperBound->withoutValue();
}
else {
// Get delta from previous record
const RedwoodRecordRef &entry = entries[i];
int deltaSize = entry.deltaSize((i == start) ? pageLowerBound : entries[i - 1]);
int keySize = entry.key.size();
int valueSize = entry.value.present() ? entry.value.get().size() : 0;
int spaceNeeded = sizeof(BTreePage::BinaryTree::Node) + deltaSize;
debug_printf("Trying to add record %3d of %3lu (i=%3d) klen %4d vlen %3d deltaSize %4d spaceNeeded %4d compressed %4d / page %4d bytes %s\n",
i + 1, entries.size(), i, keySize, valueSize, deltaSize,
spaceNeeded, compressedBytes, pageSize, entry.toString().c_str());
int spaceAvailable = pageSize - compressedBytes;
// Does it fit?
bool fits = spaceAvailable >= spaceNeeded;
// If it doesn't fit, either end the current page or increase the page size
if(!fits) {
int count = i - start;
// If not enough entries or page less than half full, increase page size to make the entry fit
if(count < minimumEntries || spaceAvailable > pageSize / 2) {
// Figure out how many additional whole or partial blocks are needed
// newBlocks = ceil ( additional space needed / block size)
int newBlocks = 1 + (spaceNeeded - spaceAvailable - 1) / blockSize;
int newPageSize = pageSize + (newBlocks * blockSize);
if(newPageSize <= BTreePage::BinaryTree::MaximumTreeSize()) {
blockCount += newBlocks;
pageSize = newPageSize;
fits = true;
}
}
if(!fits) {
pageUpperBound = entry.withoutValue();
}
}
// If the record fits then add it to the page set
if(fits) {
kvBytes += keySize + valueSize;
compressedBytes += spaceNeeded;
++i;
}
flush = !fits;
}
// If flush then write a page using records from start to i. It's guaranteed that pageUpperBound has been set above.
if(flush) {
int remaining = entries.size() - i;
end = remaining == 0; // i could have been moved above
int count = i - start;
// If
// - this is not the last page
// - the number of entries remaining after this page is less than the count of the current page
// - the page that would be written ends on a user key boundary
// Then adjust the current page item count to half the amount remaining after the start position.
if(!end && remaining < count && entries[i - 1].key != entries[i].key) {
i = (start + entries.size()) / 2;
pageUpperBound = entries[i].withoutValue();
}
// If this isn't the final page, shorten the upper boundary
if(!end && minimalBoundaries) {
int commonPrefix = pageUpperBound.getCommonPrefixLen(entries[i - 1], 0);
pageUpperBound.truncate(commonPrefix + 1);
}
state std::vector<Reference<IPage>> pages;
BTreePage *btPage;
if(blockCount == 1) {
Reference<IPage> page = self->m_pager->newPageBuffer();
btPage = (BTreePage *)page->mutate();
pages.push_back(std::move(page));
}
else {
ASSERT(blockCount > 1);
int size = blockSize * blockCount;
btPage = (BTreePage *)new uint8_t[size];
}
btPage->height = height;
btPage->kvBytes = kvBytes;
btPage->itemCount = i - start;
int written = btPage->tree().build(&entries[start], &entries[i], &pageLowerBound, &pageUpperBound);
if(written > pageSize) {
fprintf(stderr, "ERROR: Wrote %d bytes to %d byte page (%d blocks). recs %d kvBytes %d compressed %d\n", written, pageSize, blockCount, i - start, kvBytes, compressedBytes);
ASSERT(false);
}
// Create chunked pages
// TODO: Avoid copying page bytes, but this is not trivial due to how pager checksums are currently handled.
if(blockCount != 1) {
// Mark the slack in the page buffer as defined
VALGRIND_MAKE_MEM_DEFINED(((uint8_t *)btPage) + written, (blockCount * blockSize) - written);
const uint8_t *rptr = (const uint8_t *)btPage;
for(int b = 0; b < blockCount; ++b) {
Reference<IPage> page = self->m_pager->newPageBuffer();
memcpy(page->mutate(), rptr, blockSize);
rptr += 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 int p;
state BTreePageID childPageID;
// If we are only writing 1 page and it has the same BTreePageID size as the original they try to reuse the
// LogicalPageIDs in previousID and try to update them atomically.
if(end && records.empty() && previousID.size() == pages.size()) {
for(p = 0; p < pages.size(); ++p) {
LogicalPageID id = wait(self->m_pager->atomicUpdatePage(previousID[p], pages[p], 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(p = 0; p < pages.size(); ++p) {
LogicalPageID id = wait(self->m_pager->newPageID());
self->m_pager->updatePage(id, pages[p]);
childPageID.push_back(records.arena(), id);
}
}
wait(yield());
// Update activity counts
++counts.pageWrites;
if(pages.size() > 1) {
counts.extPageWrites += pages.size() - 1;
}
debug_printf("Flushing %s original=%s start=%d i=%d count=%d\nlower: %s\nupper: %s\n", toString(childPageID).c_str(), toString(previousID).c_str(), start, i, i - start, pageLowerBound.toString().c_str(), pageUpperBound.toString().c_str());
if(REDWOOD_DEBUG) {
for(int j = start; j < i; ++j) {
debug_printf(" %3d: %s\n", j, entries[j].toString().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);
if(end) {
break;
}
start = i;
kvBytes = 0;
compressedBytes = BTreePage::BinaryTree::GetTreeOverhead();
pageLowerBound = pageUpperBound.withoutValue();
}
}
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, false, &dbBegin, &dbEnd, records, height, version, BTreePageID()));
debug_printf("Wrote a new root level at version %" PRId64 " height %d size %lu pages\n", version, height, newRecords.size());
records = newRecords;
}
return records;
}
class SuperPage : public IPage, ReferenceCounted<SuperPage>, public FastAllocated<SuperPage>{
public:
SuperPage(std::vector<Reference<const IPage>> pages) {
int blockSize = pages.front()->size();
m_size = blockSize * pages.size();
m_data = new uint8_t[m_size];
uint8_t *wptr = m_data;
for(auto &p : pages) {
ASSERT(p->size() == blockSize);
memcpy(wptr, p->begin(), blockSize);
wptr += blockSize;
}
}
virtual ~SuperPage() {
delete [] m_data;
}
void addref() const {
ReferenceCounted<SuperPage>::addref();
}
void delref() const {
ReferenceCounted<SuperPage>::delref();
}
int size() const {
return m_size;
}
uint8_t const* begin() const {
return m_data;
}
uint8_t* mutate() {
return m_data;
}
private:
uint8_t *m_data;
int m_size;
};
ACTOR static Future<Reference<const IPage>> readPage(Reference<IPagerSnapshot> snapshot, BTreePageID id, const RedwoodRecordRef *lowerBound, const RedwoodRecordRef *upperBound, bool forLazyDelete = false) {
if(!forLazyDelete) {
debug_printf("readPage() op=read %s @%" PRId64 " lower=%s upper=%s\n", toString(id).c_str(), snapshot->getVersion(), lowerBound->toString().c_str(), upperBound->toString().c_str());
}
else {
debug_printf("readPage() op=readForDeferredClear %s @%" PRId64 " \n", toString(id).c_str(), snapshot->getVersion());
}
wait(yield());
state Reference<const IPage> page;
++counts.pageReads;
if(id.size() == 1) {
Reference<const IPage> p = wait(snapshot->getPhysicalPage(id.front(), !forLazyDelete, false));
page = p;
}
else {
ASSERT(!id.empty());
counts.extPageReads += (id.size() - 1);
std::vector<Future<Reference<const IPage>>> reads;
for(auto &pageID : id) {
reads.push_back(snapshot->getPhysicalPage(pageID, !forLazyDelete, false));
}
std::vector<Reference<const IPage>> pages = wait(getAll(reads));
// TODO: Cache reconstituted super pages somehow, perhaps with help from the Pager.
page = Reference<const IPage>(new SuperPage(pages));
}
debug_printf("readPage() op=readComplete %s @%" PRId64 " \n", toString(id).c_str(), snapshot->getVersion());
const BTreePage *pTreePage = (const BTreePage *)page->begin();
if(!forLazyDelete && page->userData == nullptr) {
debug_printf("readPage() Creating Reader for %s @%" PRId64 " lower=%s upper=%s\n", toString(id).c_str(), snapshot->getVersion(), lowerBound->toString().c_str(), upperBound->toString().c_str());
page->userData = new BTreePage::BinaryTree::Reader(&pTreePage->tree(), lowerBound, upperBound);
page->userDataDestructor = [](void *ptr) { delete (BTreePage::BinaryTree::Reader *)ptr; };
}
if(!forLazyDelete) {
debug_printf("readPage() %s\n", pTreePage->toString(false, id, snapshot->getVersion(), lowerBound, upperBound).c_str());
}
return page;
}
static void preLoadPage(IPagerSnapshot *snapshot, BTreePageID id) {
++counts.pagePreloads;
counts.extPagePreloads += (id.size() - 1);
for(auto pageID : id) {
snapshot->getPhysicalPage(pageID, true, true);
}
}
void freeBtreePage(BTreePageID btPageID, Version v) {
// Free individual pages at v
for(LogicalPageID id : btPageID) {
m_pager->freePage(id, v);
}
}
// Returns list of (version, internal page records, required upper bound)
ACTOR static Future<Standalone<VersionedChildrenT>> commitSubtree(VersionedBTree *self, MutationBufferT *mutationBuffer, Reference<IPagerSnapshot> snapshot, BTreePageID rootID, bool isLeaf, const RedwoodRecordRef *lowerBound, const RedwoodRecordRef *upperBound, const RedwoodRecordRef *decodeLowerBound, const RedwoodRecordRef *decodeUpperBound) {
state std::string context;
if(REDWOOD_DEBUG) {
context = format("CommitSubtree(root=%s): ", toString(rootID).c_str());
}
state Standalone<VersionedChildrenT> results;
debug_printf("%s lower=%s upper=%s\n", context.c_str(), lowerBound->toString().c_str(), upperBound->toString().c_str());
debug_printf("%s decodeLower=%s decodeUpper=%s\n", context.c_str(), decodeLowerBound->toString().c_str(), decodeUpperBound->toString().c_str());
self->counts.commitToPageStart++;
// Find the slice of the mutation buffer that is relevant to this subtree
// TODO: Rather than two lower_bound searches, perhaps just compare each mutation to the upperBound key while iterating
state MutationBufferT::const_iterator iMutationBoundary = mutationBuffer->upper_bound(lowerBound->key);
--iMutationBoundary;
state MutationBufferT::const_iterator iMutationBoundaryEnd = mutationBuffer->lower_bound(upperBound->key);
if(REDWOOD_DEBUG) {
debug_printf("%s ---------MUTATION BUFFER SLICE ---------------------\n", context.c_str());
auto begin = iMutationBoundary;
while(1) {
debug_printf("%s Mutation: '%s': %s\n", context.c_str(), printable(begin->first).c_str(), begin->second.toString().c_str());
if(begin == iMutationBoundaryEnd) {
break;
}
++begin;
}
debug_printf("%s -------------------------------------\n", context.c_str());
}
// iMutationBoundary is greatest boundary <= lowerBound->key
// iMutationBoundaryEnd is least boundary >= upperBound->key
// If the boundary range iterators are the same then this subtree only has one unique key, which is the same key as the boundary
// record the iterators are pointing to. There only two outcomes possible: Clearing the subtree or leaving it alone.
// If there are any changes to the one key then the entire subtree should be deleted as the changes for the key
// do not go into this subtree.
if(iMutationBoundary == iMutationBoundaryEnd) {
if(iMutationBoundary->second.keyChanged()) {
debug_printf("%s lower and upper bound key/version match and key is modified so deleting page, returning %s\n", context.c_str(), toString(results).c_str());
Version firstKeyChangeVersion = self->singleVersion ? self->getLastCommittedVersion() + 1 : iMutationBoundary->second.startKeyMutations.begin()->first;
if(isLeaf) {
self->freeBtreePage(rootID, firstKeyChangeVersion);
}
else {
self->m_lazyDeleteQueue.pushBack(LazyDeleteQueueEntry{firstKeyChangeVersion, rootID});
}
return results;
}
// Otherwise, no changes to this subtree
results.push_back_deep(results.arena(), VersionAndChildrenRef(0, VectorRef<RedwoodRecordRef>((RedwoodRecordRef *)decodeLowerBound, 1), *decodeUpperBound));
debug_printf("%s page contains a single key '%s' which is not changing, returning %s\n", context.c_str(), lowerBound->key.toString().c_str(), toString(results).c_str());
return results;
}
// If one mutation range covers the entire subtree, then check if the entire subtree is modified,
// unmodified, or possibly/partially modified.
MutationBufferT::const_iterator iMutationBoundaryNext = iMutationBoundary;
++iMutationBoundaryNext;
if(iMutationBoundaryNext == iMutationBoundaryEnd) {
// Cleared means the entire range covering the subtree was cleared. It is assumed true
// if the range starting after the lower mutation boundary was cleared, and then proven false
// below if possible.
bool cleared = iMutationBoundary->second.rangeCleared();
// Unchanged means the entire range covering the subtree was unchanged, it is assumed to be the
// opposite of cleared() and then proven false below if possible.
bool unchanged = !cleared;
debug_printf("%s cleared=%d unchanged=%d\n", context.c_str(), cleared, unchanged);
// If the lower mutation boundary key is the same as the subtree lower bound then whether or not
// that key is being changed or cleared affects this subtree.
if(iMutationBoundary->first == lowerBound->key) {
// If subtree will be cleared (so far) but the lower boundary key is not cleared then the subtree is not cleared
if(cleared && !iMutationBoundary->second.keyCleared()) {
cleared = false;
debug_printf("%s cleared=%d unchanged=%d\n", context.c_str(), cleared, unchanged);
}
// If the subtree looked unchanged (so far) but the lower boundary is is changed then the subtree is changed
if(unchanged && iMutationBoundary->second.keyChanged()) {
unchanged = false;
debug_printf("%s cleared=%d unchanged=%d\n", context.c_str(), cleared, unchanged);
}
}
// If the higher mutation boundary key is the same as the subtree upper bound key then whether
// or not it is being changed or cleared affects this subtree.
if((cleared || unchanged) && iMutationBoundaryEnd->first == upperBound->key) {
// If the key is being changed then the records in this subtree with the same key must be removed
// so the subtree is definitely not unchanged, though it may be cleared to achieve the same effect.
if(iMutationBoundaryEnd->second.keyChanged()) {
unchanged = false;
debug_printf("%s cleared=%d unchanged=%d\n", context.c_str(), cleared, unchanged);
}
else {
// If the key is not being changed then the records in this subtree can't be removed so the
// subtree is not being cleared.
cleared = false;
debug_printf("%s cleared=%d unchanged=%d\n", context.c_str(), cleared, unchanged);
}
}
// The subtree cannot be both cleared and unchanged.
ASSERT(!(cleared && unchanged));
// If no changes in subtree
if(unchanged) {
results.push_back_deep(results.arena(), VersionAndChildrenRef(0, VectorRef<RedwoodRecordRef>((RedwoodRecordRef *)decodeLowerBound, 1), *decodeUpperBound));
debug_printf("%s no changes on this subtree, returning %s\n", context.c_str(), toString(results).c_str());
return results;
}
// If subtree is cleared
if(cleared) {
debug_printf("%s %s cleared, deleting it, returning %s\n", context.c_str(), isLeaf ? "Page" : "Subtree", toString(results).c_str());
Version clearVersion = self->singleVersion ? self->getLastCommittedVersion() + 1 : iMutationBoundary->second.rangeClearVersion.get();
if(isLeaf) {
self->freeBtreePage(rootID, clearVersion);
}
else {
self->m_lazyDeleteQueue.pushBack(LazyDeleteQueueEntry{clearVersion, rootID});
}
return results;
}
}
self->counts.commitToPage++;
state Reference<const IPage> rawPage = wait(readPage(snapshot, rootID, decodeLowerBound, decodeUpperBound));
state BTreePage *page = (BTreePage *) rawPage->begin();
ASSERT(isLeaf == page->isLeaf());
debug_printf("%s commitSubtree(): %s\n", context.c_str(), page->toString(false, rootID, snapshot->getVersion(), decodeLowerBound, decodeUpperBound).c_str());
state BTreePage::BinaryTree::Cursor cursor = getReader(rawPage)->getCursor();
cursor.moveFirst();
state Version writeVersion;
// Leaf Page
if(isLeaf) {
state Standalone<VectorRef<RedwoodRecordRef>> merged;
debug_printf("%s Leaf page, merging changes.\n", context.c_str());
// If replacement pages are written they will be at the minimum version seen in the mutations for this leaf
Version minVersion = invalidVersion;
// Now, process each mutation range and merge changes with existing data.
bool firstMutationBoundary = true;
while(iMutationBoundary != iMutationBoundaryEnd) {
debug_printf("%s New mutation boundary: '%s': %s\n", context.c_str(), printable(iMutationBoundary->first).c_str(), iMutationBoundary->second.toString().c_str());
SingleKeyMutationsByVersion::const_iterator iMutations;
// For the first mutation boundary only, if the boundary key is less than the lower bound for the page
// then skip startKeyMutations for this boundary, we're only processing this mutation range here to apply
// a possible clear to existing data.
if(firstMutationBoundary && iMutationBoundary->first < lowerBound->key) {
iMutations = iMutationBoundary->second.startKeyMutations.end();
}
else {
iMutations = iMutationBoundary->second.startKeyMutations.begin();
}
firstMutationBoundary = false;
SingleKeyMutationsByVersion::const_iterator iMutationsEnd = iMutationBoundary->second.startKeyMutations.end();
// Iterate over old versions of the mutation boundary key, outputting if necessary
bool boundaryKeyWritten = false;
while(cursor.valid() && cursor.get().key == iMutationBoundary->first) {
// If not in single version mode or there were no changes to the key
if(!self->singleVersion || iMutationBoundary->second.noChanges()) {
merged.push_back(merged.arena(), cursor.get());
debug_printf("%s Added %s [existing, boundary start]\n", context.c_str(), merged.back().toString().c_str());
boundaryKeyWritten = true;
}
else {
ASSERT(self->singleVersion);
debug_printf("%s Skipped %s [existing, boundary start, singleVersion mode]\n", context.c_str(), cursor.get().toString().c_str());
minVersion = 0;
}
cursor.moveNext();
}
// TODO: If a mutation set is equal to the previous existing value of the key, maybe don't write it.
// Output mutations for the mutation boundary start key
while(iMutations != iMutationsEnd) {
const SingleKeyMutation &m = iMutations->second;
if(m.isClear() || m.value.size() <= self->m_maxPartSize) {
// If the boundary key was not yet written to the merged list then clears can be skipped.
// Note that in a more complex scenario where there are multiple sibling pages for the same key, with different
// versions and/or part numbers, this is still a valid thing to do. This is because a changing boundary
// key (set or clear) will result in any instances (different versions, split parts) of this key
// on sibling pages to the left of this page to be removed, so an explicit clear need only be stored
// if a record with the mutation boundary key was already written to this page.
if(!boundaryKeyWritten && iMutations->second.isClear()) {
debug_printf("%s Skipped %s [mutation, unnecessary boundary key clear]\n", context.c_str(), m.toRecord(iMutationBoundary->first, iMutations->first).toString().c_str());
}
else {
merged.push_back(merged.arena(), m.toRecord(iMutationBoundary->first, iMutations->first));
debug_printf("%s Added non-split %s [mutation, boundary start]\n", context.c_str(), merged.back().toString().c_str());
if(iMutations->first < minVersion || minVersion == invalidVersion)
minVersion = iMutations->first;
boundaryKeyWritten = true;
}
}
else {
if(iMutations->first < minVersion || minVersion == invalidVersion)
minVersion = iMutations->first;
int bytesLeft = m.value.size();
int start = 0;
RedwoodRecordRef whole(iMutationBoundary->first, iMutations->first, m.value);
while(bytesLeft > 0) {
int partSize = std::min(bytesLeft, self->m_maxPartSize);
// Don't copy the value chunk because this page will stay in memory until after we've built new version(s) of it
merged.push_back(merged.arena(), whole.split(start, partSize));
bytesLeft -= partSize;
start += partSize;
debug_printf("%s Added split %s [mutation, boundary start] bytesLeft %d\n", context.c_str(), merged.back().toString().c_str(), bytesLeft);
}
boundaryKeyWritten = true;
}
++iMutations;
}
// Get the clear version for this range, which is the last thing that we need from it,
Optional<Version> clearRangeVersion = iMutationBoundary->second.rangeClearVersion;
// Advance to the next boundary because we need to know the end key for the current range.
++iMutationBoundary;
debug_printf("%s Mutation range end: '%s'\n", context.c_str(), printable(iMutationBoundary->first).c_str());
// Write existing keys which are less than the next mutation boundary key, clearing if needed.
while(cursor.valid() && cursor.get().key < iMutationBoundary->first) {
// TODO: Remove old versions that are too old
bool remove = self->singleVersion && clearRangeVersion.present();
if(!remove) {
merged.push_back(merged.arena(), cursor.get());
debug_printf("%s Added %s [existing, middle]\n", context.c_str(), merged.back().toString().c_str());
}
else {
ASSERT(self->singleVersion);
debug_printf("%s Skipped %s [existing, boundary start, singleVersion mode]\n", context.c_str(), cursor.get().toString().c_str());
Version clearVersion = clearRangeVersion.get();
if(clearVersion < minVersion || minVersion == invalidVersion)
minVersion = clearVersion;
}
// If keeping version history, write clears for records that exist in this range if the range was cleared
if(!self->singleVersion) {
// Write a clear of this key if needed. A clear is required if clearRangeVersion is set and the next cursor
// key is different than the current one. If the last cursor key in the page is different from the
// first key in the right sibling page then the page's upper bound will reflect that.
auto nextCursor = cursor;
nextCursor.moveNext();
if(clearRangeVersion.present() && cursor.get().key != nextCursor.getOrUpperBound().key) {
Version clearVersion = clearRangeVersion.get();
if(clearVersion < minVersion || minVersion == invalidVersion)
minVersion = clearVersion;
merged.push_back(merged.arena(), RedwoodRecordRef(cursor.get().key, clearVersion));
debug_printf("%s Added %s [existing, middle clear]\n", context.c_str(), merged.back().toString().c_str());
}
cursor = nextCursor;
}
else {
cursor.moveNext();
}
}
}
// Write any remaining existing keys, which are not subject to clears as they are beyond the cleared range.
bool upperMutationBoundaryKeyChanged = iMutationBoundaryEnd->second.keyChanged();
while(cursor.valid()) {
// If the upper mutation boundary is being changed and the cursor's key matches it then stop because none of the earlier
// versions or fragments of that key should be written.
if(upperMutationBoundaryKeyChanged && cursor.get().key == iMutationBoundaryEnd->first) {
debug_printf("%s Skipped %s and beyond [existing, matches changed upper mutation boundary]\n", context.c_str(), cursor.get().toString().c_str());
Version changedVersion = iMutationBoundaryEnd->second.startKeyMutations.begin()->first;
if(changedVersion < minVersion || minVersion == invalidVersion)
minVersion = changedVersion;
break;
}
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();
}
// No changes were actually made. This could happen if the only mutations are clear ranges which do not match any records.
if(minVersion == invalidVersion) {
results.push_back_deep(results.arena(), VersionAndChildrenRef(0, VectorRef<RedwoodRecordRef>((RedwoodRecordRef *)decodeLowerBound, 1), *decodeUpperBound));
debug_printf("%s No changes were made during mutation merge, returning %s\n", context.c_str(), toString(results).c_str());
return results;
}
else {
debug_printf("%s Changes were made, writing.\n", context.c_str());
}
// TODO: Make version and key splits based on contents of merged list, if keeping history
writeVersion = self->singleVersion ? self->getLastCommittedVersion() + 1 : minVersion;
// If everything in the page was deleted then this page should be deleted as of the new version
// Note that if a single range clear covered the entire page then we should not get this far
if(merged.empty()) {
debug_printf("%s All leaf page contents were cleared, returning %s\n", context.c_str(), toString(results).c_str());
self->freeBtreePage(rootID, writeVersion);
return results;
}
state Standalone<VectorRef<RedwoodRecordRef>> entries = wait(writePages(self, true, lowerBound, upperBound, merged, page->height, writeVersion, rootID));
results.arena().dependsOn(entries.arena());
results.push_back(results.arena(), VersionAndChildrenRef(writeVersion, entries, *upperBound));
debug_printf("%s Merge complete, returning %s\n", context.c_str(), toString(results).c_str());
return results;
}
else {
// Internal Page
ASSERT(!isLeaf);
state std::vector<Future<Standalone<VersionedChildrenT>>> futureChildren;
bool first = true;
while(cursor.valid()) {
// The lower bound for the first child is the lowerBound arg
const RedwoodRecordRef &childLowerBound = first ? *lowerBound : cursor.get();
first = false;
// Skip over any children that do not link to a page. They exist to preserve the ancestors from
// which adjacent children can borrow prefix bytes.
// If there are any, then the first valid child page will incur a boundary change to move
// its lower bound to the left so we can delete the non-linking entry from this page to free up space.
while(!cursor.get().value.present()) {
// There should never be an internal page written that has no valid child pages. This loop will find
// the first valid child link, and if there are no more then execution will not return to this loop.
ASSERT(cursor.moveNext());
}
ASSERT(cursor.valid());
const RedwoodRecordRef &decodeChildLowerBound = cursor.get();
BTreePageID pageID = cursor.get().getChildPage();
ASSERT(!pageID.empty());
const RedwoodRecordRef &decodeChildUpperBound = cursor.moveNext() ? cursor.get() : *decodeUpperBound;
// Skip over any next-children which do not actually link to child pages
while(cursor.valid() && !cursor.get().value.present()) {
cursor.moveNext();
}
const RedwoodRecordRef &childUpperBound = cursor.valid() ? cursor.get() : *upperBound;
debug_printf("%s recursing to %s lower=%s upper=%s decodeLower=%s decodeUpper=%s\n",
context.c_str(), toString(pageID).c_str(), childLowerBound.toString().c_str(), childUpperBound.toString().c_str(), decodeChildLowerBound.toString().c_str(), decodeChildUpperBound.toString().c_str());
/*
// TODO: If lower bound and upper bound have the same key, do something intelligent if possible
//
if(childLowerBound.key == childUpperBound.key) {
if(key is modified or cleared) {
if(self->singleVersion) {
// In single version mode, don't keep any records with the old key if the key is modified, so return
// an empty page set to replace the child page
futureChildren.push_back(VersionedChildrenT({ {0,{} } }));
}
else {
// In versioned mode, there is no need to recurse to this page because new versions of key
// will go in the right most page that has the same lowerBound key, but since the key is
// being changed the new version of this page should exclude the old subtree
}
else {
// Return the child page as-is, no need to visit it
futureChildren.push_back(VersionedChildrenT({ {0,{{childLowerBound, pageID}}} }));
}
}
else {
// No changes
futureChildren.push_back(VersionedChildrenT({ {0,{{childLowerBound, pageID}}} }));
}
}
else {
futureChildren.push_back(self->commitSubtree(self, mutationBuffer, snapshot, pageID, &childLowerBound, &childUpperBound));
}
*/
// If this page has height of 2 then its children are leaf nodes
futureChildren.push_back(self->commitSubtree(self, mutationBuffer, snapshot, pageID, page->height == 2, &childLowerBound, &childUpperBound, &decodeChildLowerBound, &decodeChildUpperBound));
}
// Waiting one at a time makes debugging easier
// TODO: Is it better to use waitForAll()?
state int k;
for(k = 0; k < futureChildren.size(); ++k) {
wait(success(futureChildren[k]));
}
if(REDWOOD_DEBUG) {
debug_printf("%s Subtree update results\n", context.c_str());
for(int i = 0; i < futureChildren.size(); ++i) {
debug_printf("%s subtree result %s\n", context.c_str(), toString(futureChildren[i].get()).c_str());
}
}
// TODO: Either handle multi-versioned results or change commitSubtree interface to return a single child set.
ASSERT(self->singleVersion);
writeVersion = self->getLastCommittedVersion() + 1;
cursor.moveFirst();
// All of the things added to pageBuilder will exist in the arenas inside futureChildren or will be upperBound
InternalPageBuilder pageBuilder(cursor);
for(int i = 0; i < futureChildren.size(); ++i) {
VersionedChildrenT versionedChildren = futureChildren[i].get();
ASSERT(versionedChildren.size() <= 1);
if(!versionedChildren.empty()) {
pageBuilder.addEntries(versionedChildren.front());
}
}
pageBuilder.finalize(*upperBound, *decodeUpperBound);
// If page contents have changed
if(pageBuilder.modified) {
// If the page now has no children
if(pageBuilder.childPageCount == 0) {
debug_printf("%s All internal page children were deleted so deleting this page too, returning %s\n", context.c_str(), toString(results).c_str());
self->freeBtreePage(rootID, writeVersion);
return results;
}
else {
debug_printf("%s Internal page modified, creating replacements.\n", context.c_str());
debug_printf("%s newChildren=%s lastUpperBound=%s upperBound=%s\n", context.c_str(), toString(pageBuilder.entries).c_str(), pageBuilder.lastUpperBound.toString().c_str(), upperBound->toString().c_str());
ASSERT(pageBuilder.lastUpperBound == *upperBound);
Standalone<VectorRef<RedwoodRecordRef>> childEntries = wait(holdWhile(pageBuilder.entries, writePages(self, false, lowerBound, upperBound, pageBuilder.entries, page->height, writeVersion, rootID)));
results.arena().dependsOn(childEntries.arena());
results.push_back(results.arena(), VersionAndChildrenRef(0, childEntries, *upperBound));
debug_printf("%s Internal modified, returning %s\n", context.c_str(), toString(results).c_str());
return results;
}
}
else {
results.push_back_deep(results.arena(), VersionAndChildrenRef(0, VectorRef<RedwoodRecordRef>((RedwoodRecordRef *)decodeLowerBound, 1), *decodeUpperBound));
debug_printf("%s Page has no changes, returning %s\n", context.c_str(), toString(results).c_str());
return results;
}
}
}
ACTOR static Future<Void> commit_impl(VersionedBTree *self) {
state MutationBufferT *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 that started 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);
state bool lazyDeleteStop = false;
state Future<int> lazyDelete = incrementalSubtreeClear(self, &lazyDeleteStop);
// 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<BTreePageID> rootPageID = self->m_header.root.get();
state RedwoodRecordRef lowerBound = dbBegin.withPageID(rootPageID);
Standalone<VersionedChildrenT> versionedRoots = wait(commitSubtree(self, mutations, self->m_pager->getReadSnapshot(latestVersion), rootPageID, self->m_header.height == 1, &lowerBound, &dbEnd, &lowerBound, &dbEnd));
debug_printf("CommitSubtree(root %s) returned %s\n", toString(rootPageID).c_str(), toString(versionedRoots).c_str());
// CommitSubtree on the root can only return 1 child at most because the pager interface only supports writing
// one meta record (which contains the root page) per commit.
ASSERT(versionedRoots.size() <= 1);
// If the old root was deleted, write a new empty tree root node and free the old roots
if(versionedRoots.empty()) {
debug_printf("Writing new empty root.\n");
LogicalPageID newRootID = wait(self->m_pager->newPageID());
Reference<IPage> page = self->m_pager->newPageBuffer();
makeEmptyRoot(page);
self->m_header.height = 1;
self->m_pager->updatePage(newRootID, page);
rootPageID = BTreePageID((LogicalPageID *)&newRootID, 1);
}
else {
Standalone<VectorRef<RedwoodRecordRef>> newRootLevel(versionedRoots.front().children, versionedRoots.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));
lazyDeleteStop = true;
wait(success(lazyDelete));
debug_printf("Lazy delete freed %u pages\n", lazyDelete.get());
self->m_pager->setCommitVersion(writeVersion);
wait(self->m_lazyDeleteQueue.flush());
self->m_header.lazyDeleteQueue = self->m_lazyDeleteQueue.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;
++counts.commits;
committed.send(Void());
return Void();
}
// InternalCursor is for seeking to and iterating over the 'internal' records (not user-visible) in the Btree.
// These records are versioned and they can represent deletedness or partial values.
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;
BTreePageID pageID; // Only needed for debugging purposes
Reference<const IPage> 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(BTreePageID id, Reference<const IPage> page, Reference<PageCursor> parent = {})
: pageID(id), page(page), parent(parent), cursor(getReader().getCursor())
{
}
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 Reference<PageCursor>(new PageCursor(*this));
}
const BTreePage * btPage() const {
return (const BTreePage *)page->begin();
}
// Multiple InternalCursors can share a Page
BTreePage::BinaryTree::Reader & getReader() const {
return *(BTreePage::BinaryTree::Reader *)page->userData;
}
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();
BTreePageID id = rec.getChildPage();
Future<Reference<const IPage>> child = readPage(pager, id, &rec, &next.getOrUpperBound());
// Read ahead siblings at level 2
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 IPage> page) {
return Reference<PageCursor>(new PageCursor(id, page, Reference<PageCursor>::addRef(this)));
});
}
std::string toString() const {
return format("%s, %s", ::toString(pageID).c_str(), cursor.valid() ? cursor.get().toString().c_str() : "<invalid>");
}
};
Standalone<BTreePageID> rootPageID;
Reference<IPagerSnapshot> pager;
Reference<PageCursor> pageCursor;
public:
InternalCursor() {
}
InternalCursor(Reference<IPagerSnapshot> pager, BTreePageID 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() {
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;
}
// 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 IPage>> root = readPage(pager, rootPageID, &dbBegin, &dbEnd);
return map(root, [=](Reference<const IPage> p) {
pageCursor = Reference<PageCursor>(new PageCursor(rootPageID, p));
return Void();
});
}
ACTOR Future<bool> seekLessThanOrEqual_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 success = self->pageCursor->cursor.seekLessThanOrEqual(query);
// Skip backwards 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 = self->pageCursor->cursor.movePrev();
}
}
if(success) {
// If we found a record <= query at a leaf page then return success
if(self->pageCursor->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> seekLTE(RedwoodRecordRef query, int prefetchBytes) {
return seekLessThanOrEqual_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 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, BTreePageID root, Version recordVersion)
: m_version(recordVersion),
m_cur1(pageSource, root),
m_cur2(m_cur1)
{
}
void addref() { ReferenceCounted<Cursor>::addref(); }
void delref() { 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 = false) 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) {
// Search for the last key at or before (key, version, \xff)
state RedwoodRecordRef query(key, self->m_version, {}, 0, std::numeric_limits<int32_t>::max());
self->m_kv.reset();
wait(success(self->m_cur1.seekLTE(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, reading full KV pair. Cursor: %s\n", self->toString().c_str());
wait(self->readFullKVPair(self));
return Void();
}
// Mode is ==, so if we're still here we didn't find it.
if(cmp == 0) {
return Void();
}
// Mode is >=, so if we're here we have to go to the next present record at the target version
// because the seek done above was <= query
if(cmp > 0) {
// icur is at a record < query or invalid.
// If cursor is invalid, try to go to start of tree
if(!self->m_cur1.valid()) {
bool valid = wait(self->m_cur1.moveFirst());
if(!valid) {
self->m_kv.reset();
return Void();
}
}
else {
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) {
// Mode is <=, which is the same as the seekLTE(query)
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.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
//
// cur2 must be the record immediately after cur1
// TODO: This may already be the case, store state to track this condition and avoid the reset here
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)));
}
self->m_kv.reset();
while(self->m_cur1.valid()) {
if(self->m_cur1.presentAtVersion(self->m_version) &&
(!self->m_cur2.validAtVersion(self->m_version) ||
self->m_cur2.get().key != self->m_cur1.get().key)
) {
wait(readFullKVPair(self));
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());
return Void();
}
// Read all of the current key-value record starting at cur1 into kv
ACTOR static Future<Void> readFullKVPair(Cursor *self) {
self->m_arena = Arena();
const RedwoodRecordRef &rec = self->m_cur1.get();
self->m_kv.reset();
debug_printf("readFullKVPair: Starting at %s\n", self->toString().c_str());
// Unsplit value, cur1 will hold the key and value memory
if(!rec.isMultiPart()) {
self->m_kv = KeyValueRef(rec.key, rec.value.get());
debug_printf("readFullKVPair: Unsplit, exit. %s\n", self->toString().c_str());
return Void();
}
debug_printf("readFullKVPair: Split, first record %s\n", rec.toString().c_str());
// Split value, need to coalesce split value parts into a buffer in arena,
// after which cur1 will point to the first part and kv.key will reference its key
ASSERT(rec.chunk.start + rec.value.get().size() == rec.chunk.total);
// Allocate space for the entire value in the same arena as the key
state int bytesLeft = rec.chunk.total;
state StringRef dst = makeString(bytesLeft, self->m_arena);
loop {
const RedwoodRecordRef &rec = self->m_cur1.get();
debug_printf("readFullKVPair: Adding chunk %s\n", rec.toString().c_str());
int partSize = rec.value.get().size();
memcpy(mutateString(dst) + rec.chunk.start, rec.value.get().begin(), partSize);
bytesLeft -= partSize;
if(bytesLeft == 0) {
self->m_kv = KeyValueRef(rec.key, dst);
return Void();
}
ASSERT(bytesLeft > 0);
// Move backward
bool success = wait(self->m_cur1.move(false));
ASSERT(success);
}
}
};
};
RedwoodRecordRef VersionedBTree::dbBegin(StringRef(), 0);
RedwoodRecordRef VersionedBTree::dbEnd(LiteralStringRef("\xff\xff\xff\xff\xff"));
VersionedBTree::Counts VersionedBTree::counts;
class KeyValueStoreRedwoodUnversioned : public IKeyValueStore {
public:
KeyValueStoreRedwoodUnversioned(std::string filePrefix, UID logID) : m_filePrefix(filePrefix) {
// TODO: This constructor should really just take an IVersionedStore
IPager2 *pager = new DWALPager(4096, filePrefix, 0);
m_tree = new VersionedBTree(pager, filePrefix, true);
m_init = catchError(init_impl(this));
}
Future<Void> init() {
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() {
shutdown(this, false);
}
void dispose() {
shutdown(this, true);
}
Future< Void > onClosed() {
return m_closed.getFuture();
}
Future<Void> commit(bool sequential = false) {
Future<Void> c = m_tree->commit();
m_tree->setOldestVersion(m_tree->getLatestVersion());
m_tree->setWriteVersion(m_tree->getWriteVersion() + 1);
return catchError(c);
}
KeyValueStoreType getType() {
return KeyValueStoreType::SSD_REDWOOD_V1;
}
StorageBytes getStorageBytes() {
return m_tree->getStorageBytes();
}
Future< Void > getError() {
return delayed(m_error.getFuture());
};
void clear(KeyRangeRef range, const Arena* arena = 0) {
debug_printf("CLEAR %s\n", printable(range).c_str());
m_tree->clear(range);
}
void set( KeyValueRef keyValue, const Arena* arena = NULL ) {
debug_printf("SET %s\n", keyValue.key.printable().c_str());
m_tree->set(keyValue);
}
Future< Standalone< VectorRef< KeyValueRef > > > readRange(KeyRangeRef keys, int rowLimit = 1<<30, int byteLimit = 1<<30) {
debug_printf("READRANGE %s\n", printable(keys).c_str());
return catchError(readRange_impl(this, keys, rowLimit, byteLimit));
}
ACTOR static Future< Standalone< VectorRef< KeyValueRef > > > readRange_impl(KeyValueStoreRedwoodUnversioned *self, KeyRange keys, int rowLimit, int byteLimit) {
self->m_tree->counts.getRanges++;
state Standalone<VectorRef<KeyValueRef>> result;
state int accumulatedBytes = 0;
ASSERT( byteLimit > 0 );
state Reference<IStoreCursor> cur = self->m_tree->readAtVersion(self->m_tree->getLastCommittedVersion());
// Prefetch is currently only done in the forward direction
state int prefetchBytes = rowLimit > 1 ? byteLimit : 0;
if(rowLimit >= 0) {
wait(cur->findFirstEqualOrGreater(keys.begin, prefetchBytes));
while(cur->isValid() && cur->getKey() < keys.end) {
KeyValueRef kv(KeyRef(result.arena(), cur->getKey()), ValueRef(result.arena(), cur->getValue()));
accumulatedBytes += kv.expectedSize();
result.push_back(result.arena(), kv);
if(--rowLimit == 0 || accumulatedBytes >= byteLimit) {
break;
}
wait(cur->next());
}
} else {
wait(cur->findLastLessOrEqual(keys.end));
if(cur->isValid() && cur->getKey() == keys.end)
wait(cur->prev());
while(cur->isValid() && cur->getKey() >= keys.begin) {
KeyValueRef kv(KeyRef(result.arena(), cur->getKey()), ValueRef(result.arena(), cur->getValue()));
accumulatedBytes += kv.expectedSize();
result.push_back(result.arena(), kv);
if(++rowLimit == 0 || accumulatedBytes >= byteLimit) {
break;
}
wait(cur->prev());
}
}
return result;
}
ACTOR static Future< Optional<Value> > readValue_impl(KeyValueStoreRedwoodUnversioned *self, Key key, Optional< UID > debugID) {
self->m_tree->counts.gets++;
state Reference<IStoreCursor> cur = self->m_tree->readAtVersion(self->m_tree->getLastCommittedVersion());
wait(cur->findEqual(key));
if(cur->isValid()) {
return cur->getValue();
}
return Optional<Value>();
}
Future< Optional< Value > > readValue(KeyRef key, Optional< UID > debugID = Optional<UID>()) {
return catchError(readValue_impl(this, key, debugID));
}
ACTOR static Future< Optional<Value> > readValuePrefix_impl(KeyValueStoreRedwoodUnversioned *self, Key key, int maxLength, Optional< UID > debugID) {
self->m_tree->counts.gets++;
state Reference<IStoreCursor> cur = self->m_tree->readAtVersion(self->m_tree->getLastCommittedVersion());
wait(cur->findEqual(key));
if(cur->isValid()) {
Value v = cur->getValue();
int len = std::min(v.size(), maxLength);
return Value(cur->getValue().substr(0, len));
}
return Optional<Value>();
}
Future< Optional< Value > > readValuePrefix(KeyRef key, int maxLength, Optional< UID > debugID = Optional<UID>()) {
return catchError(readValuePrefix_impl(this, key, maxLength, debugID));
}
virtual ~KeyValueStoreRedwoodUnversioned() {
};
private:
std::string m_filePrefix;
VersionedBTree *m_tree;
Future<Void> m_init;
Promise<Void> m_closed;
Promise<Void> m_error;
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;
}
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.toString().c_str(), end.toString().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.toString().c_str(), end.toString().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.toString().c_str(), end.toString().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.toString().c_str(), end.toString().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.toString().c_str(), end.toString().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' vs written '%s'\n", v, start.toString().c_str(), end.toString().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' vs written '%s'\n", v, start.toString().c_str(), end.toString().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.toString().c_str(), end.toString().c_str(), iLast->first.second, iLast->first.first.c_str());
}
debug_printf("VerifyRangeReverse(@%" PRId64 ", %s, %s): start\n", v, start.toString().c_str(), end.toString().c_str());
// Randomly use a new cursor for the reverse range read but only if version history is available
if(!btree->isSingleVersion() && 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.toString().c_str(), end.toString().c_str(), cur->getKey().toString().c_str());
break;
}
if(cur->getKey() != r->key) {
++errors;
++*pErrorCount;
printf("VerifyRangeReverse(@%" PRId64 ", %s, %s) ERROR: Tree key '%s' vs written '%s'\n", v, start.toString().c_str(), end.toString().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' vs written '%s'\n", v, start.toString().c_str(), end.toString().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.toString().c_str(), end.toString().c_str(), r->key.toString().c_str());
}
return errors;
}
ACTOR Future<int> verifyAll(VersionedBTree *btree, Version maxCommittedVersion, std::map<std::pair<std::string, Version>, Optional<std::string>> *written, int *pErrorCount) {
// Read back every key at every version set or cleared and verify the result.
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;
while(i != iEnd) {
state std::string key = i->first.first;
state Version ver = i->first.second;
if(ver <= maxCommittedVersion) {
state Optional<std::string> val = i->second;
state Reference<IStoreCursor> cur = btree->readAtVersion(ver);
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;
}
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> vall;
state Future<int> vrange;
try {
loop {
state Version v = waitNext(vStream);
if(btree->isSingleVersion()) {
v = btree->getLastCommittedVersion();
debug_printf("Verifying at latest committed version %" PRId64 "\n", v);
vall = verifyRange(btree, LiteralStringRef(""), LiteralStringRef("\xff\xff"), v, written, pErrorCount);
if(serial) {
wait(success(vall));
}
vrange = verifyRange(btree, randomKV().key, randomKV().key, v, written, pErrorCount);
if(serial) {
wait(success(vrange));
}
}
else {
debug_printf("Verifying through version %" PRId64 "\n", v);
vall = verifyAll(btree, v, written, pErrorCount);
if(serial) {
wait(success(vall));
}
vrange = verifyRange(btree, randomKV().key, randomKV().key, deterministicRandom()->randomInt(1, v + 1), written, pErrorCount);
if(serial) {
wait(success(vrange));
}
}
wait(success(vall) && success(vrange));
debug_printf("Verified through 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() > .1) {
Version v = btree->getLastCommittedVersion();
if(!btree->isSingleVersion()) {
v = deterministicRandom()->randomInt(1, v + 1);
}
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;
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;
}
int size() const {
return sizeof(Delta);
}
std::string toString() const {
return format("DELTA{prefixSource=%d dk=%d(0x%x) dv=%d(0x%x)}", prefixSource, dk, dk, dv, dv);
}
};
int compare(const IntIntPair &rhs) const {
//printf("compare %s to %s\n", toString().c_str(), rhs.toString().c_str());
return k - rhs.k;
}
bool operator==(const IntIntPair &rhs) const {
return k == rhs.k;
}
int getCommonPrefixLen(const IntIntPair &other, int skip) const {
return 0;
}
int deltaSize(const IntIntPair &base) const {
return sizeof(Delta);
}
int writeDelta(Delta &d, const IntIntPair &base, int commonPrefix = -1) const {
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 getCommonIntFieldPrefix2(const RedwoodRecordRef &a, const RedwoodRecordRef &b) {
RedwoodRecordRef::byte aFields[RedwoodRecordRef::intFieldArraySize];
RedwoodRecordRef::byte bFields[RedwoodRecordRef::intFieldArraySize];
a.serializeIntFields(aFields);
b.serializeIntFields(bFields);
//printf("a: %s\n", StringRef(aFields, RedwoodRecordRef::intFieldArraySize).toHexString().c_str());
//printf("b: %s\n", StringRef(bFields, RedwoodRecordRef::intFieldArraySize).toHexString().c_str());
int i = 0;
while(i < RedwoodRecordRef::intFieldArraySize && aFields[i] == bFields[i]) {
++i;
}
//printf("%d\n", i);
return i;
}
void deltaTest(RedwoodRecordRef rec, RedwoodRecordRef base) {
char buf[500];
RedwoodRecordRef::Delta &d = *(RedwoodRecordRef::Delta *)buf;
Arena mem;
int expectedSize = rec.deltaSize(base, false);
int deltaSize = rec.writeDelta(d, base);
RedwoodRecordRef decoded = d.apply(base, mem);
if(decoded != rec || expectedSize != deltaSize) {
printf("\n");
printf("Base: %s\n", base.toString().c_str());
printf("ExpectedSize: %d\n", expectedSize);
printf("DeltaSize: %d\n", deltaSize);
printf("Delta: %s\n", d.toString().c_str());
printf("Record: %s\n", rec.toString().c_str());
printf("Decoded: %s\n", decoded.toString().c_str());
printf("RedwoodRecordRef::Delta test failure!\n");
ASSERT(false);
}
}
Standalone<RedwoodRecordRef> randomRedwoodRecordRef(int maxKeySize = 3, int maxValueSize = 255) {
RedwoodRecordRef rec;
KeyValue kv = randomKV(3, 10);
rec.key = kv.key;
if(deterministicRandom()->random01() < .9) {
rec.value = kv.value;
}
rec.version = deterministicRandom()->coinflip() ? 0 : deterministicRandom()->randomInt64(0, std::numeric_limits<Version>::max());
if(deterministicRandom()->coinflip()) {
rec.chunk.total = deterministicRandom()->randomInt(1, 100000);
rec.chunk.start = deterministicRandom()->randomInt(0, rec.chunk.total);
}
return Standalone<RedwoodRecordRef>(rec, kv.arena());
}
TEST_CASE("!/redwood/correctness/unit/RedwoodRecordRef") {
// Test pageID stuff.
{
LogicalPageID ids[] = {1, 5};
BTreePageID 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());
}
// Testing common prefix calculation for integer fields using the member function that calculates this directly
// and by serializing the integer fields to arrays and finding the common prefix length of the two arrays
deltaTest(RedwoodRecordRef(LiteralStringRef(""), 0, LiteralStringRef(""), 0, 0),
RedwoodRecordRef(LiteralStringRef(""), 0, LiteralStringRef(""), 0, 0)
);
deltaTest(RedwoodRecordRef(LiteralStringRef("abc"), 0, LiteralStringRef(""), 0, 0),
RedwoodRecordRef(LiteralStringRef("abc"), 0, LiteralStringRef(""), 0, 0)
);
deltaTest(RedwoodRecordRef(LiteralStringRef("abc"), 0, LiteralStringRef(""), 0, 0),
RedwoodRecordRef(LiteralStringRef("abcd"), 0, LiteralStringRef(""), 0, 0)
);
deltaTest(RedwoodRecordRef(LiteralStringRef("abc"), 2, LiteralStringRef(""), 0, 0),
RedwoodRecordRef(LiteralStringRef("abc"), 2, LiteralStringRef(""), 0, 0)
);
deltaTest(RedwoodRecordRef(LiteralStringRef("abc"), 2, LiteralStringRef(""), 0, 0),
RedwoodRecordRef(LiteralStringRef("ab"), 2, LiteralStringRef(""), 1, 3)
);
deltaTest(RedwoodRecordRef(LiteralStringRef("abc"), 2, LiteralStringRef(""), 5, 0),
RedwoodRecordRef(LiteralStringRef("abc"), 2, LiteralStringRef(""), 5, 1)
);
RedwoodRecordRef::byte varInts[100];
RedwoodRecordRef::Writer w(varInts);
RedwoodRecordRef::Reader r(varInts);
w.writeVarInt(1);
w.writeVarInt(128);
w.writeVarInt(32000);
ASSERT(r.readVarInt() == 1);
ASSERT(r.readVarInt() == 128);
ASSERT(r.readVarInt() == 32000);
RedwoodRecordRef rec1;
RedwoodRecordRef rec2;
rec1.version = 0x12345678;
rec2.version = 0x12995678;
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == 5);
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == getCommonIntFieldPrefix2(rec1, rec2));
rec1.version = 0x12345678;
rec2.version = 0x12345678;
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == 14);
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == getCommonIntFieldPrefix2(rec1, rec2));
rec1.version = invalidVersion;
rec2.version = 0;
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == 0);
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == getCommonIntFieldPrefix2(rec1, rec2));
rec1.version = 0x12345678;
rec2.version = 0x12345678;
rec1.chunk.total = 4;
rec2.chunk.total = 4;
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == 14);
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == getCommonIntFieldPrefix2(rec1, rec2));
rec1.version = 0x12345678;
rec2.version = 0x12345678;
rec1.chunk.start = 4;
rec2.chunk.start = 4;
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == 14);
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == getCommonIntFieldPrefix2(rec1, rec2));
rec1.version = 0x12345678;
rec2.version = 0x12345678;
rec1.chunk.start = 4;
rec2.chunk.start = 5;
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == 13);
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == getCommonIntFieldPrefix2(rec1, rec2));
rec1.version = 0x12345678;
rec2.version = 0x12345678;
rec1.chunk.total = 256;
rec2.chunk.total = 512;
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == 9);
ASSERT(rec1.getCommonIntFieldPrefix(rec2) == getCommonIntFieldPrefix2(rec1, rec2));
Arena mem;
double start;
uint64_t total;
uint64_t count;
uint64_t i;
start = timer();
total = 0;
count = 1e9;
for(i = 0; i < count; ++i) {
rec1.chunk.total = i & 0xffffff;
rec2.chunk.total = i & 0xffffff;
rec1.chunk.start = i & 0xffffff;
rec2.chunk.start = (i + 1) & 0xffffff;
total += rec1.getCommonIntFieldPrefix(rec2);
}
printf("%" PRId64 " getCommonIntFieldPrefix() %g M/s\n", total, count / (timer() - start) / 1e6);
rec1.key = LiteralStringRef("alksdfjaklsdfjlkasdjflkasdjfklajsdflk;ajsdflkajdsflkjadsf");
rec2.key = LiteralStringRef("alksdfjaklsdfjlkasdjflkasdjfklajsdflk;ajsdflkajdsflkjadsf");
start = timer();
total = 0;
count = 1e9;
for(i = 0; i < count; ++i) {
RedwoodRecordRef::byte fields[RedwoodRecordRef::intFieldArraySize];
rec1.chunk.start = i & 0xffffff;
rec2.chunk.start = (i + 1) & 0xffffff;
rec1.serializeIntFields(fields);
total += fields[RedwoodRecordRef::intFieldArraySize - 1];
}
printf("%" PRId64 " serializeIntFields() %g M/s\n", total, count / (timer() - start) / 1e6);
start = timer();
total = 0;
count = 100e6;
for(i = 0; i < count; ++i) {
rec1.chunk.start = i & 0xffffff;
rec2.chunk.start = (i + 1) & 0xffffff;
total += rec1.getCommonPrefixLen(rec2, 50);
}
printf("%" PRId64 " getCommonPrefixLen(skip=50) %g M/s\n", total, count / (timer() - start) / 1e6);
start = timer();
total = 0;
count = 100e6;
for(i = 0; i < count; ++i) {
rec1.chunk.start = i & 0xffffff;
rec2.chunk.start = (i + 1) & 0xffffff;
total += rec1.getCommonPrefixLen(rec2, 0);
}
printf("%" PRId64 " getCommonPrefixLen(skip=0) %g 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) {
rec1.chunk.start = i & 0xffffff;
rec2.chunk.start = (i + 1) & 0xffffff;
total += rec1.writeDelta(d, rec2, commonPrefix);
}
printf("%" PRId64 " writeDelta(commonPrefix=%d) %g M/s\n", total, commonPrefix, count / (timer() - start) / 1e6);
start = timer();
total = 0;
count = 10e6;
for(i = 0; i < count; ++i) {
rec1.chunk.start = i & 0xffffff;
rec2.chunk.start = (i + 1) & 0xffffff;
total += rec1.writeDelta(d, rec2);
}
printf("%" PRId64 " writeDelta() %g M/s\n", total, count / (timer() - start) / 1e6);
start = timer();
total = 0;
count = 1e6;
for(i = 0; i < count; ++i) {
Standalone<RedwoodRecordRef> a = randomRedwoodRecordRef();
Standalone<RedwoodRecordRef> b = randomRedwoodRecordRef();
deltaTest(a, b);
}
printf("Random deltaTest() %g M/s\n", count / (timer() - start) / 1e6);
return Void();
}
TEST_CASE("!/redwood/correctness/unit/deltaTree/RedwoodRecordRef") {
const int N = 200;
RedwoodRecordRef prev;
RedwoodRecordRef next(LiteralStringRef("\xff\xff\xff\xff"));
Arena arena;
std::vector<RedwoodRecordRef> items;
for(int i = 0; i < N; ++i) {
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(deterministicRandom()->coinflip()) {
rec.chunk.start = deterministicRandom()->randomInt(0, 100000);
rec.chunk.total = rec.chunk.start + v.size() + deterministicRandom()->randomInt(0, 100000);
}
}
items.push_back(rec);
//printf("i=%d %s\n", i, items.back().toString().c_str());
}
std::sort(items.begin(), items.end());
DeltaTree<RedwoodRecordRef> *tree = (DeltaTree<RedwoodRecordRef> *) new uint8_t[N * 100];
tree->build(&items[0], &items[items.size()], &prev, &next);
printf("Count=%d Size=%d InitialDepth=%d\n", (int)items.size(), (int)tree->size(), (int)tree->initialDepth);
debug_printf("Data(%p): %s\n", tree, StringRef((uint8_t *)tree, tree->size()).toHexString().c_str());
DeltaTree<RedwoodRecordRef>::Reader r(tree, &prev, &next);
DeltaTree<RedwoodRecordRef>::Cursor fwd = r.getCursor();
DeltaTree<RedwoodRecordRef>::Cursor rev = r.getCursor();
DeltaTree<RedwoodRecordRef, RedwoodRecordRef::DeltaValueOnly>::Reader rValuesOnly(tree, &prev, &next);
DeltaTree<RedwoodRecordRef, RedwoodRecordRef::DeltaValueOnly>::Cursor fwdValueOnly = rValuesOnly.getCursor();
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().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().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().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());
double start = timer();
DeltaTree<RedwoodRecordRef>::Cursor c = r.getCursor();
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);
return Void();
}
TEST_CASE("!/redwood/correctness/unit/deltaTree/IntIntPair") {
const int N = 200;
IntIntPair prev = {0, 0};
IntIntPair next = {1000, 0};
std::vector<IntIntPair> items;
for(int i = 0; i < N; ++i) {
items.push_back({i*10, i*1000});
//printf("i=%d %s\n", i, items.back().toString().c_str());
}
DeltaTree<IntIntPair> *tree = (DeltaTree<IntIntPair> *) new uint8_t[10000];
tree->build(&items[0], &items[items.size()], &prev, &next);
printf("Count=%d Size=%d InitialDepth=%d\n", (int)items.size(), (int)tree->size(), (int)tree->initialDepth);
debug_printf("Data(%p): %s\n", tree, StringRef((uint8_t *)tree, tree->size()).toHexString().c_str());
DeltaTree<IntIntPair>::Reader r(tree, &prev, &next);
DeltaTree<IntIntPair>::Cursor fwd = r.getCursor();
DeltaTree<IntIntPair>::Cursor rev = r.getCursor();
ASSERT(fwd.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());
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());
ASSERT(false);
}
++i;
ASSERT(fwd.moveNext() == rev.movePrev());
ASSERT(fwd.valid() == rev.valid());
if(!fwd.valid()) {
break;
}
}
ASSERT(i == items.size());
DeltaTree<IntIntPair>::Cursor c = r.getCursor();
double start = timer();
for(int i = 0; i < 20000000; ++i) {
IntIntPair p({deterministicRandom()->randomInt(0, items.size() * 10), 0});
if(!c.seekLessThanOrEqual(p)) {
printf("Not found! query=%s\n", p.toString().c_str());
ASSERT(false);
}
if(c.get().k != (p.k - (p.k % 10))) {
printf("Found incorrect node! query=%s found=%s\n", p.toString().c_str(), c.get().toString().c_str());
ASSERT(false);
}
}
double elapsed = timer() - start;
printf("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/correctness/btree") {
state std::string pagerFile = "unittest_pageFile.redwood";
IPager2 *pager;
state bool serialTest = deterministicRandom()->coinflip();
state bool shortTest = deterministicRandom()->coinflip();
state bool singleVersion = true; // Multi-version mode is broken / not finished
state int pageSize = shortTest ? 200 : (deterministicRandom()->coinflip() ? 4096 : deterministicRandom()->randomInt(200, 400));
// We must be able to fit at least two any two keys plus overhead in a page to prevent
// a situation where the tree cannot be grown upward with decreasing level size.
state int maxKeySize = deterministicRandom()->randomInt(4, pageSize * 2);
state int maxValueSize = deterministicRandom()->randomInt(0, pageSize * 4);
state int maxCommitSize = shortTest ? 1000 : randomSize(std::min<int>((maxKeySize + maxValueSize) * 20000, 10e6));
state int mutationBytesTarget = shortTest ? 5000 : randomSize(std::min<int>(maxCommitSize * 100, 100e6));
state double clearProbability = deterministicRandom()->random01() * .1;
state double clearPostSetProbability = deterministicRandom()->random01() * .1;
state double coldStartProbability = deterministicRandom()->random01();
state double advanceOldVersionProbability = deterministicRandom()->random01();
state double maxDuration = 60;
printf("\n");
printf("serialTest: %d\n", serialTest);
printf("shortTest: %d\n", shortTest);
printf("singleVersion: %d\n", serialTest);
printf("pageSize: %d\n", pageSize);
printf("maxKeySize: %d\n", maxKeySize);
printf("maxValueSize: %d\n", maxValueSize);
printf("maxCommitSize: %d\n", maxCommitSize);
printf("mutationBytesTarget: %d\n", mutationBytesTarget);
printf("clearProbability: %f\n", clearProbability);
printf("clearPostSetProbability: %f\n", clearPostSetProbability);
printf("coldStartProbability: %f\n", coldStartProbability);
printf("advanceOldVersionProbability: %f\n", advanceOldVersionProbability);
printf("\n");
printf("Deleting existing test data...\n");
deleteFile(pagerFile);
printf("Initializing...\n");
state double startTime = now();
pager = new DWALPager(pageSize, pagerFile, 0);
state VersionedBTree *btree = new VersionedBTree(pager, pagerFile, singleVersion);
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());
state Future<Void> commit = Void();
while(mutationBytes.get() < mutationBytesTarget && (now() - startTime) < maxDuration) {
if(now() - startTime > 600) {
mutationBytesTarget = mutationBytes.get();
}
// Sometimes advance 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;
}
if(end == start)
end = keyAfter(start);
else if(end < start) {
std::swap(end, start);
}
++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();
}
// Sometimes set the range end after the clear
if(deterministicRandom()->random01() < clearPostSetProbability) {
KeyValue kv = randomKV(0, maxValueSize);
kv.key = range.end;
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 at end or after this commit's mutation bytes are reached
if(mutationBytes.get() >= mutationBytesTarget || mutationBytesThisCommit >= mutationBytesTargetThisCommit) {
// Wait for previous commit to finish
wait(commit);
printf("Committed. Next commit %d bytes, %" PRId64 "/%d (%.2f%%) Stats: Insert %.2f MB/s ClearedKeys %.2f MB/s Total %.2f\n",
mutationBytesThisCommit,
mutationBytes.get(),
mutationBytesTarget,
(double)mutationBytes.get() / mutationBytesTarget * 100,
(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()->randomInt(0, btree->getLastCommittedVersion() - btree->getOldestVersion() + 1));
}
commit = map(btree->commit(), [=](Void) {
printf("Committed: %s\n", VersionedBTree::counts.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(!serialTest && 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, pagerFile, 0);
btree = new VersionedBTree(pager, pagerFile, singleVersion);
wait(btree->init());
Version v = btree->getLatestVersion();
ASSERT(v == version);
printf("Recovered from disk. Latest version %" PRId64 "\n", v);
// 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();
}
++version;
btree->setWriteVersion(version);
}
// Check for errors
if(errorCount != 0)
throw internal_error();
}
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
if(errorCount != 0)
throw internal_error();
wait(btree->destroyAndCheckSanity());
Future<Void> 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);
wait(success(pager->init()));
state LogicalPageID id = wait(pager->newPageID());
Reference<IPage> p = pager->newPageBuffer();
memset(p->mutate(), (char)id, p->size());
pager->updatePage(id, p);
pager->setMetaKey(LiteralStringRef("asdfasdf"));
wait(pager->commit());
Reference<IPage> 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;
VersionedBTree::counts.clear();
// If a test file is passed in by environment then don't write new data to it.
state bool reload = getenv("TESTFILE") == nullptr;
state std::string pagerFile = reload ? "unittest.redwood" : getenv("TESTFILE");
if(reload) {
printf("Deleting old test data\n");
deleteFile(pagerFile);
}
state int pageSize = 4096;
state int64_t pageCacheBytes = FLOW_KNOBS->PAGE_CACHE_4K;
DWALPager *pager = new DWALPager(pageSize, pagerFile, pageCacheBytes);
state bool singleVersion = true;
state VersionedBTree *btree = new VersionedBTree(pager, pagerFile, singleVersion);
wait(btree->init());
state int nodeCount = 1e9;
state int maxChangesPerVersion = 5000;
state int64_t kvBytesTarget = 4e9;
state int commitTarget = 20e6;
state int minKeyPrefixBytes = 0;
state int maxKeyPrefixBytes = 25;
state int minValueSize = 0;
state int maxValueSize = 500;
state int maxConsecutiveRun = 10;
state char firstKeyChar = 'a';
state char lastKeyChar = 'b';
printf("pageSize: %d\n", pageSize);
printf("pageCacheBytes: %" PRId64 "\n", pageCacheBytes);
printf("trailingIntegerIndexRange: %d\n", nodeCount);
printf("maxChangesPerVersion: %d\n", maxChangesPerVersion);
printf("minKeyPrefixBytes: %d\n", minKeyPrefixBytes);
printf("maxKeyPrefixBytes: %d\n", maxKeyPrefixBytes);
printf("maxConsecutiveRun: %d\n", maxConsecutiveRun);
printf("minValueSize: %d\n", minValueSize);
printf("maxValueSize: %d\n", maxValueSize);
printf("commitTarget: %d\n", commitTarget);
printf("kvBytesTarget: %" PRId64 "\n", kvBytesTarget);
printf("KeyLexicon '%c' to '%c'\n", firstKeyChar, lastKeyChar);
state int64_t kvBytes = 0;
state int64_t kvBytesTotal = 0;
state int records = 0;
state Future<Void> commit = Void();
state std::string value(maxValueSize, 'v');
printf("Starting.\n");
state double intervalStart = timer();
state double start = intervalStart;
if(reload) {
while(kvBytesTotal < kvBytesTarget) {
wait(yield());
Version lastVer = btree->getLatestVersion();
state Version version = lastVer + 1;
btree->setWriteVersion(version);
int changes = deterministicRandom()->randomInt(0, maxChangesPerVersion);
while(changes > 0 && kvBytes < commitTarget) {
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(1, maxConsecutiveRun + 1);
while(runLength > 0 && changes > 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;
--changes;
kvBytes += kv.key.size() + kv.value.size();
++records;
}
}
if(kvBytes >= commitTarget) {
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 = records;
int kvb = kvBytes;
// 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: %s\n", VersionedBTree::counts.toString(true).c_str());
double elapsed = timer() - *pIntervalStart;
printf("Committed %d kvBytes in %d records in %f seconds, %.2f MB/s\n", kvb, recs, elapsed, kvb / elapsed / 1e6);
*pIntervalStart = timer();
return Void();
});
kvBytesTotal += kvBytes;
kvBytes = 0;
records = 0;
}
}
wait(commit);
printf("Cumulative %.2f MB keyValue bytes written at %.2f MB/s\n", kvBytesTotal / 1e6, kvBytesTotal / (timer() - start) / 1e6);
}
int seeks = 1e6;
printf("Warming cache with seeks\n");
actors.add(randomSeeks(btree, seeks/3, firstKeyChar, lastKeyChar));
actors.add(randomSeeks(btree, seeks/3, firstKeyChar, lastKeyChar));
actors.add(randomSeeks(btree, seeks/3, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats: %s\n", VersionedBTree::counts.toString(true).c_str());
state int ops = 10000;
printf("Serial scans with adaptive readAhead...\n");
actors.add(randomScans(btree, ops, 50, -1, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats: %s\n", VersionedBTree::counts.toString(true).c_str());
printf("Serial scans with readAhead 3 pages...\n");
actors.add(randomScans(btree, ops, 50, 12000, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats: %s\n", VersionedBTree::counts.toString(true).c_str());
printf("Serial scans with readAhead 2 pages...\n");
actors.add(randomScans(btree, ops, 50, 8000, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats: %s\n", VersionedBTree::counts.toString(true).c_str());
printf("Serial scans with readAhead 1 page...\n");
actors.add(randomScans(btree, ops, 50, 4000, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats: %s\n", VersionedBTree::counts.toString(true).c_str());
printf("Serial scans...\n");
actors.add(randomScans(btree, ops, 50, 0, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats: %s\n", VersionedBTree::counts.toString(true).c_str());
printf("Serial seeks...\n");
actors.add(randomSeeks(btree, ops, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats: %s\n", VersionedBTree::counts.toString(true).c_str());
printf("Parallel seeks...\n");
actors.add(randomSeeks(btree, ops, firstKeyChar, lastKeyChar));
actors.add(randomSeeks(btree, ops, firstKeyChar, lastKeyChar));
actors.add(randomSeeks(btree, ops, firstKeyChar, lastKeyChar));
wait(actors.signalAndReset());
printf("Stats: %s\n", VersionedBTree::counts.toString(true).c_str());
Future<Void> closedFuture = btree->onClosed();
btree->close();
wait(closedFuture);
return Void();
}