foundationdb/fdbserver/StorageCache.actor.cpp

2229 lines
89 KiB
C++

/*
* StorageCache.actor.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2019 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/Arena.h"
#include "fdbclient/FDBOptions.g.h"
#include "fdbclient/NativeAPI.actor.h"
#include "fdbclient/SystemData.h"
#include "fdbserver/Knobs.h"
#include "fdbserver/ServerDBInfo.h"
#include "fdbclient/StorageServerInterface.h"
#include "fdbclient/VersionedMap.h"
#include "fdbclient/KeyRangeMap.h"
#include "fdbclient/Atomic.h"
#include "fdbclient/Notified.h"
#include "fdbserver/LogProtocolMessage.h"
#include "fdbserver/LogSystem.h"
#include "fdbserver/MutationTracking.h"
#include "fdbserver/WaitFailure.h"
#include "fdbserver/WorkerInterface.actor.h"
#include "fdbclient/DatabaseContext.h"
#include "fdbclient/NativeAPI.actor.h"
#include "flow/Trace.h"
#include "flow/actorcompiler.h" // This must be the last #include.
// TODO storageCache server shares quite a bit of storageServer functionality, although simplified
// Need to look into refactoring common code out for better code readability and to avoid duplication
namespace {
// TODO rename wrong_shard_server error to wrong_cache_server
bool canReplyWith(Error e) {
switch (e.code()) {
case error_code_transaction_too_old:
case error_code_future_version:
case error_code_wrong_shard_server:
case error_code_cold_cache_server:
case error_code_process_behind:
// case error_code_all_alternatives_failed:
return true;
default:
return false;
};
}
} // namespace
class StorageCacheUpdater;
struct AddingCacheRange : NonCopyable {
KeyRange keys;
Future<Void> fetchClient; // holds FetchKeys() actor
Promise<Void> fetchComplete;
Promise<Void> readWrite;
std::deque<Standalone<VerUpdateRef>>
updates; // during the Fetching phase, mutations with key in keys and version>=(fetchClient's) fetchVersion;
struct StorageCacheData* server;
Version transferredVersion;
enum Phase { WaitPrevious, Fetching, Waiting };
Phase phase;
AddingCacheRange(StorageCacheData* server, KeyRangeRef const& keys);
~AddingCacheRange() {
if (!fetchComplete.isSet())
fetchComplete.send(Void());
if (!readWrite.isSet())
readWrite.send(Void());
}
void addMutation(Version version, MutationRef const& mutation);
bool isTransferred() const { return phase == Waiting; }
};
class CacheRangeInfo : public ReferenceCounted<CacheRangeInfo>, NonCopyable {
CacheRangeInfo(KeyRange keys, std::unique_ptr<AddingCacheRange>&& adding, StorageCacheData* readWrite)
: adding(std::move(adding)), readWrite(readWrite), keys(keys) {}
public:
std::unique_ptr<AddingCacheRange> adding;
struct StorageCacheData* readWrite;
KeyRange keys;
uint64_t changeCounter;
static CacheRangeInfo* newNotAssigned(KeyRange keys) { return new CacheRangeInfo(keys, nullptr, nullptr); }
static CacheRangeInfo* newReadWrite(KeyRange keys, StorageCacheData* data) {
return new CacheRangeInfo(keys, nullptr, data);
}
static CacheRangeInfo* newAdding(StorageCacheData* data, KeyRange keys) {
return new CacheRangeInfo(keys, std::make_unique<AddingCacheRange>(data, keys), nullptr);
}
bool isReadable() const { return readWrite != nullptr; }
bool isAdding() const { return adding != nullptr; }
bool notAssigned() const { return !readWrite && !adding; }
bool assigned() const { return readWrite || adding; }
bool isInVersionedData() const { return readWrite || (adding && adding->isTransferred()); }
void addMutation(Version version, MutationRef const& mutation);
bool isFetched() const { return readWrite || (adding && adding->fetchComplete.isSet()); }
const char* debugDescribeState() const {
if (notAssigned())
return "NotAssigned";
else if (adding && !adding->isTransferred())
return "AddingFetching";
else if (adding)
return "AddingTransferred";
else
return "ReadWrite";
}
};
const int VERSION_OVERHEAD =
64 + sizeof(Version) + sizeof(Standalone<VerUpdateRef>) + // mutationLog, 64b overhead for map
2 * (64 + sizeof(Version) +
sizeof(
Reference<VersionedMap<KeyRef,
ValueOrClearToRef>::PTreeT>)); // versioned map [ x2 for createNewVersion(version+1)
// ], 64b overhead for map
static int mvccStorageBytes(MutationRef const& m) {
return VersionedMap<KeyRef, ValueOrClearToRef>::overheadPerItem * 2 +
(MutationRef::OVERHEAD_BYTES + m.param1.size() + m.param2.size()) * 2;
}
struct FetchInjectionInfo {
Arena arena;
vector<VerUpdateRef> changes;
};
struct StorageCacheData {
typedef VersionedMap<KeyRef, ValueOrClearToRef> VersionedData;
// typedef VersionedMap<KeyRef, ValueOrClearToRef, FastAllocPTree<KeyRef>> VersionedData;
private:
// in-memory versioned struct (PTree as of now. Subject to change)
VersionedData versionedData;
// in-memory mutationLog that the versionedData contains references to
// TODO change it to a deque, already contains mutations in version order
std::map<Version, Standalone<VerUpdateRef>> mutationLog; // versions (durableVersion, version]
public:
UID thisServerID; // unique id
uint16_t index; // server index
ProtocolVersion logProtocol;
Reference<ILogSystem> logSystem;
Key ck; // cacheKey
Reference<AsyncVar<ServerDBInfo>> const& db;
Database cx;
StorageCacheUpdater* updater;
// KeyRangeMap <bool> cachedRangeMap; // map of cached key-ranges
KeyRangeMap<Reference<CacheRangeInfo>> cachedRangeMap; // map of cached key-ranges
uint64_t cacheRangeChangeCounter; // Max( CacheRangeInfo->changecounter )
// TODO Add cache metrics, such as available memory/in-use memory etc to help dat adistributor assign cached ranges
// StorageCacheMetrics metrics;
// newestAvailableVersion[k]
// == invalidVersion -> k is unavailable at all versions
// <= compactVersion -> k is unavailable at all versions
// == v -> k is readable (from versionedData) @ (oldestVersion,v], and not being updated when version
// increases
// == latestVersion -> k is readable (from versionedData) @ (oldestVersion,version.get()], and thus stays
// available when version increases
CoalescedKeyRangeMap<Version> newestAvailableVersion;
CoalescedKeyRangeMap<Version> newestDirtyVersion; // Similar to newestAvailableVersion, but includes (only) keys
// that were only partly available (due to cancelled fetchKeys)
// The following are in rough order from newest to oldest
// TODO double check which ones we need for storageCache servers
Version lastTLogVersion, lastVersionWithData;
Version peekVersion; // version to peek the log at
NotifiedVersion version; // current version i.e. the max version that can be read from the cache
NotifiedVersion desiredOldestVersion; // oldestVersion can be increased to this after compaction
NotifiedVersion oldestVersion; // Min version that might be read from the cache
// TODO not really in use as of now. may need in some failure cases. Revisit and remove if no plausible use
Future<Void> compactionInProgress;
FlowLock updateVersionLock;
FlowLock fetchKeysParallelismLock;
vector<Promise<FetchInjectionInfo*>> readyFetchKeys;
// TODO do we need otherError here?
Promise<Void> otherError;
Promise<Void> coreStarted;
bool debug_inApplyUpdate;
double debug_lastValidateTime;
int64_t versionLag; // An estimate for how many versions it takes for the data to move from the logs to this cache
// server
bool behind;
// TODO double check which ones we need for storageCache servers
struct Counters {
CounterCollection cc;
Counter allQueries, getKeyQueries, getValueQueries, getRangeQueries, finishedQueries, rowsQueried, bytesQueried;
Counter bytesInput, bytesFetched, mutationBytes; // Like bytesInput but without MVCC accounting
Counter mutations, setMutations, clearRangeMutations, atomicMutations;
Counter updateBatches, updateVersions;
Counter loops;
Counter readsRejected;
// LatencyBands readLatencyBands;
Counters(StorageCacheData* self)
: cc("StorageCacheServer", self->thisServerID.toString()), getKeyQueries("GetKeyQueries", cc),
getValueQueries("GetValueQueries", cc), getRangeQueries("GetRangeQueries", cc),
allQueries("QueryQueue", cc), finishedQueries("FinishedQueries", cc), rowsQueried("RowsQueried", cc),
bytesQueried("BytesQueried", cc), bytesInput("BytesInput", cc), bytesFetched("BytesFetched", cc),
mutationBytes("MutationBytes", cc), mutations("Mutations", cc), setMutations("SetMutations", cc),
clearRangeMutations("ClearRangeMutations", cc), atomicMutations("AtomicMutations", cc),
updateBatches("UpdateBatches", cc), updateVersions("UpdateVersions", cc), loops("Loops", cc),
readsRejected("ReadsRejected", cc) {
specialCounter(cc, "LastTLogVersion", [self]() { return self->lastTLogVersion; });
specialCounter(cc, "Version", [self]() { return self->version.get(); });
specialCounter(cc, "VersionLag", [self]() { return self->versionLag; });
}
} counters;
explicit StorageCacheData(UID thisServerID, uint16_t index, Reference<AsyncVar<ServerDBInfo>> const& db)
: /*versionedData(FastAllocPTree<KeyRef>{std::make_shared<int>(0)}), */
thisServerID(thisServerID), index(index), logProtocol(0), db(db), cacheRangeChangeCounter(0),
lastTLogVersion(0), lastVersionWithData(0), peekVersion(0), compactionInProgress(Void()),
fetchKeysParallelismLock(SERVER_KNOBS->FETCH_KEYS_PARALLELISM_BYTES), debug_inApplyUpdate(false),
debug_lastValidateTime(0), versionLag(0), behind(false), counters(this) {
version.initMetric(LiteralStringRef("StorageCacheData.Version"), counters.cc.id);
desiredOldestVersion.initMetric(LiteralStringRef("StorageCacheData.DesriedOldestVersion"), counters.cc.id);
oldestVersion.initMetric(LiteralStringRef("StorageCacheData.OldestVersion"), counters.cc.id);
newestAvailableVersion.insert(allKeys, invalidVersion);
newestDirtyVersion.insert(allKeys, invalidVersion);
addCacheRange(CacheRangeInfo::newNotAssigned(allKeys));
cx = openDBOnServer(db, TaskPriority::DefaultEndpoint, true, true);
}
// Puts the given cacheRange into cachedRangeMap. The caller is responsible for adding cacheRanges
// for all ranges in cachedRangeMap.getAffectedRangesAfterInsertion(newCacheRange->keys)), because these
// cacheRanges are invalidated by the call.
void addCacheRange(CacheRangeInfo* newCacheRange) {
ASSERT(!newCacheRange->keys.empty());
newCacheRange->changeCounter = ++cacheRangeChangeCounter;
//TraceEvent(SevDebug, "AddCacheRange", this->thisServerID).detail("KeyBegin", newCacheRange->keys.begin).detail("KeyEnd", newCacheRange->keys.end).
// detail("State", newCacheRange->isReadable() ? "Readable" : newCacheRange->notAssigned() ? "NotAssigned" :
// "Adding").detail("Version", this->version.get());
cachedRangeMap.insert(newCacheRange->keys, Reference<CacheRangeInfo>(newCacheRange));
}
void addMutation(KeyRangeRef const& cachedKeyRange, Version version, MutationRef const& mutation);
void applyMutation(MutationRef const& m, Arena& arena, VersionedData& data);
bool isReadable(KeyRangeRef const& keys) {
auto cr = cachedRangeMap.intersectingRanges(keys);
for (auto i = cr.begin(); i != cr.end(); ++i)
if (!i->value()->isReadable())
return false;
return true;
}
void checkChangeCounter(uint64_t oldCacheRangeChangeCounter, KeyRef const& key) {
if (oldCacheRangeChangeCounter != cacheRangeChangeCounter &&
cachedRangeMap[key]->changeCounter > oldCacheRangeChangeCounter) {
TEST(true); // CacheRange change during getValueQ
// TODO: should we throw the cold_cache_server() error here instead?
throw wrong_shard_server();
}
}
void checkChangeCounter(uint64_t oldCacheRangeChangeCounter, KeyRangeRef const& keys) {
if (oldCacheRangeChangeCounter != cacheRangeChangeCounter) {
auto sh = cachedRangeMap.intersectingRanges(keys);
for (auto i = sh.begin(); i != sh.end(); ++i)
if (i->value()->changeCounter > oldCacheRangeChangeCounter) {
TEST(true); // CacheRange change during range operation
// TODO: should we throw the cold_cache_server() error here instead?
throw wrong_shard_server();
}
}
}
Arena lastArena;
std::map<Version, Standalone<VerUpdateRef>> const& getMutationLog() const { return mutationLog; }
std::map<Version, Standalone<VerUpdateRef>>& getMutableMutationLog() { return mutationLog; }
VersionedData const& data() const { return versionedData; }
VersionedData& mutableData() { return versionedData; }
Standalone<VerUpdateRef>& addVersionToMutationLog(Version v) {
// return existing version...
auto m = mutationLog.find(v);
if (m != mutationLog.end())
return m->second;
// ...or create a new one
auto& u = mutationLog[v];
u.version = v;
if (lastArena.getSize() >= 65536)
lastArena = Arena(4096);
u.arena() = lastArena;
counters.bytesInput += VERSION_OVERHEAD;
return u;
}
MutationRef addMutationToMutationLog(Standalone<VerUpdateRef>& mLV, MutationRef const& m) {
// TODO find out more
// byteSampleApplyMutation(m, mLV.version);
counters.bytesInput += mvccStorageBytes(m);
return mLV.push_back_deep(mLV.arena(), m);
}
};
void applyMutation(StorageCacheUpdater* updater, StorageCacheData* data, MutationRef const& mutation, Version version);
/////////////////////////////////// Validation ///////////////////////////////////////
#pragma region Validation
bool validateCacheRange(StorageCacheData::VersionedData::ViewAtVersion const& view,
KeyRangeRef range,
Version version,
UID id,
Version minInsertVersion) {
// * Nonoverlapping: No clear overlaps a set or another clear, or adjoins another clear.
// * Old mutations are erased: All items in versionedData.atLatest() have insertVersion() > oldestVersion()
//TraceEvent(SevDebug, "ValidateRange", id).detail("KeyBegin", range.begin).detail("KeyEnd", range.end).detail("Version", version);
KeyRef k;
bool ok = true;
bool kIsClear = false;
auto i = view.lower_bound(range.begin);
if (i != view.begin())
--i;
for (; i != view.end() && i.key() < range.end; ++i) {
// TODO revisit this check. there could be nodes in PTree that were inserted, but never updated. their
// insertVersion thus maybe lower than the current oldest version of the versioned map
// if (i.insertVersion() <= minInsertVersion)
// TraceEvent(SevError,"SCValidateCacheRange",id).detail("IKey", i.key()).detail("Version",
// version).detail("InsertVersion", i.insertVersion()).detail("MinInsertVersion", minInsertVersion); ASSERT(
// i.insertVersion() > minInsertVersion );
if (kIsClear && i->isClearTo() ? i.key() <= k : i.key() < k) {
TraceEvent(SevError, "SCInvalidRange", id)
.detail("Key1", k)
.detail("Key2", i.key())
.detail("Version", version);
ok = false;
}
// ASSERT( i.key() >= k );
kIsClear = i->isClearTo();
k = kIsClear ? i->getEndKey() : i.key();
}
return ok;
}
void validate(StorageCacheData* data, bool force = false) {
try {
if (force || (EXPENSIVE_VALIDATION)) {
data->newestAvailableVersion.validateCoalesced();
data->newestDirtyVersion.validateCoalesced();
for (auto range = data->cachedRangeMap.ranges().begin(); range != data->cachedRangeMap.ranges().end();
++range) {
ASSERT(range->value()->keys == range->range());
ASSERT(!range->value()->keys.empty());
}
for (auto range = data->cachedRangeMap.ranges().begin(); range != data->cachedRangeMap.ranges().end();
++range)
if (range->value()->isReadable()) {
auto ar = data->newestAvailableVersion.intersectingRanges(range->range());
for (auto a = ar.begin(); a != ar.end(); ++a)
ASSERT(a->value() == latestVersion);
}
// * versionedData contains versions [oldestVersion.get(), version.get()]. It might also contain later
// versions if applyUpdate is on the stack.
ASSERT(data->data().getOldestVersion() == data->oldestVersion.get());
ASSERT(data->data().getLatestVersion() == data->version.get() ||
data->data().getLatestVersion() == data->version.get() + 1 ||
(data->debug_inApplyUpdate && data->data().getLatestVersion() > data->version.get()));
auto latest = data->data().atLatest();
latest.validate();
validateCacheRange(latest, allKeys, data->version.get(), data->thisServerID, data->oldestVersion.get());
data->debug_lastValidateTime = now();
//TraceEvent(SevDebug, "SCValidationDone", data->thisServerID).detail("LastValidTime", data->debug_lastValidateTime);
}
} catch (...) {
TraceEvent(SevError, "SCValidationFailure", data->thisServerID)
.detail("LastValidTime", data->debug_lastValidateTime);
throw;
}
}
#pragma endregion
///////////////////////////////////// Queries /////////////////////////////////
#pragma region Queries
ACTOR Future<Version> waitForVersion(StorageCacheData* data, Version version) {
// This could become an Actor transparently, but for now it just does the lookup
if (version == latestVersion)
version = std::max(Version(1), data->version.get());
if (version < data->oldestVersion.get() || version <= 0)
throw transaction_too_old();
else if (version <= data->version.get())
return version;
if (data->behind && version > data->version.get()) {
throw process_behind();
}
if (deterministicRandom()->random01() < 0.001)
TraceEvent("WaitForVersion1000x");
choose {
when(wait(data->version.whenAtLeast(version))) {
// FIXME: A bunch of these can block with or without the following delay 0.
// wait( delay(0) ); // don't do a whole bunch of these at once
if (version < data->oldestVersion.get())
throw transaction_too_old();
return version;
}
when(wait(delay(SERVER_KNOBS->FUTURE_VERSION_DELAY))) {
if (deterministicRandom()->random01() < 0.001)
TraceEvent(SevWarn, "CacheServerFutureVersion1000x", data->thisServerID)
.detail("Version", version)
.detail("MyVersion", data->version.get())
.detail("ServerID", data->thisServerID);
throw future_version();
}
}
}
ACTOR Future<Version> waitForVersionNoTooOld(StorageCacheData* data, Version version) {
// This could become an Actor transparently, but for now it just does the lookup
if (version == latestVersion)
version = std::max(Version(1), data->version.get());
if (version <= data->version.get())
return version;
choose {
when(wait(data->version.whenAtLeast(version))) { return version; }
when(wait(delay(SERVER_KNOBS->FUTURE_VERSION_DELAY))) {
if (deterministicRandom()->random01() < 0.001)
TraceEvent(SevWarn, "CacheServerFutureVersion1000x", data->thisServerID)
.detail("Version", version)
.detail("MyVersion", data->version.get())
.detail("ServerID", data->thisServerID);
throw future_version();
}
}
}
ACTOR Future<Void> getValueQ(StorageCacheData* data, GetValueRequest req) {
state int64_t resultSize = 0;
try {
++data->counters.getValueQueries;
++data->counters.allQueries;
//++data->readQueueSizeMetric;
// TODO later
// data->maxQueryQueue = std::max<int>( data->maxQueryQueue, data->counters.allQueries.getValue() -
// data->counters.finishedQueries.getValue());
// Active load balancing runs at a very high priority (to obtain accurate queue lengths)
// so we need to downgrade here
// TODO what's this?
wait(delay(0, TaskPriority::DefaultEndpoint));
if (req.debugID.present()) {
g_traceBatch.addEvent("GetValueDebug",
req.debugID.get().first(),
"getValueQ.DoRead"); //.detail("TaskID", g_network->getCurrentTask());
// FIXME
}
state Optional<Value> v;
state Version version = wait(waitForVersion(data, req.version));
if (req.debugID.present())
g_traceBatch.addEvent("GetValueDebug",
req.debugID.get().first(),
"getValueQ.AfterVersion"); //.detail("TaskID", g_network->getCurrentTask());
state uint64_t changeCounter = data->cacheRangeChangeCounter;
if (data->cachedRangeMap[req.key]->notAssigned()) {
//TraceEvent(SevWarn, "WrongCacheServer", data->thisServerID).detail("Key", req.key).detail("ReqVersion", req.version).detail("DataVersion", data->version.get()).detail("In", "getValueQ");
throw wrong_shard_server();
} else if (!data->cachedRangeMap[req.key]->isReadable()) {
//TraceEvent(SevWarn, "ColdCacheServer", data->thisServerID).detail("Key", req.key).detail("IsAdding", data->cachedRangeMap[req.key]->isAdding())
// .detail("ReqVersion", req.version).detail("DataVersion", data->version.get()).detail("In", "getValueQ");
throw future_version();
}
state int path = 0;
auto i = data->data().at(version).lastLessOrEqual(req.key);
if (i && i->isValue() && i.key() == req.key) {
v = (Value)i->getValue();
path = 1;
// TODO: do we need to check changeCounter here?
data->checkChangeCounter(changeCounter, req.key);
}
// DEBUG_MUTATION("CacheGetValue", version, MutationRef(MutationRef::DebugKey, req.key,
// v.present()?v.get():LiteralStringRef("<null>"))); DEBUG_MUTATION("CacheGetPath", version,
// MutationRef(MutationRef::DebugKey, req.key,
// path==0?LiteralStringRef("0"):path==1?LiteralStringRef("1"):LiteralStringRef("2")));
if (v.present()) {
++data->counters.rowsQueried;
resultSize = v.get().size();
data->counters.bytesQueried += resultSize;
//TraceEvent(SevDebug, "SCGetValueQPresent", data->thisServerID).detail("ResultSize",resultSize).detail("Version", version).detail("ReqKey",req.key).detail("Value",v);
}
if (req.debugID.present())
g_traceBatch.addEvent("GetValueDebug",
req.debugID.get().first(),
"getValueQ.AfterRead"); //.detail("TaskID", g_network->getCurrentTask());
GetValueReply reply(v, true);
req.reply.send(reply);
} catch (Error& e) {
//TraceEvent(SevWarn, "SCGetValueQError", data->thisServerID).detail("Code",e.code()).detail("ReqKey",req.key)
// .detail("ReqVersion", req.version).detail("DataVersion", data->version.get());
if (!canReplyWith(e))
throw;
req.reply.sendError(e);
}
++data->counters.finishedQueries;
//--data->readQueueSizeMetric;
// if(data->latencyBandConfig.present()) {
// int maxReadBytes =
// data->latencyBandConfig.get().readConfig.maxReadBytes.orDefault(std::numeric_limits<int>::max());
// data->counters.readLatencyBands.addMeasurement(timer() - req.requestTime(), resultSize > maxReadBytes);
//}
return Void();
};
GetKeyValuesReply readRange(StorageCacheData* data, Version version, KeyRangeRef range, int limit, int* pLimitBytes) {
GetKeyValuesReply result;
StorageCacheData::VersionedData::ViewAtVersion view = data->data().at(version);
StorageCacheData::VersionedData::iterator vCurrent = view.end();
KeyRef readBegin;
KeyRef readEnd;
KeyRef rangeBegin = range.begin;
KeyRef rangeEnd = range.end;
int accumulatedBytes = 0;
// printf("\nSCReadRange\n");
// if (limit >= 0) we are reading forward, else backward
if (limit >= 0) {
// We might care about a clear beginning before start that runs into range
vCurrent = view.lastLessOrEqual(rangeBegin);
if (vCurrent && vCurrent->isClearTo() && vCurrent->getEndKey() > rangeBegin)
readBegin = vCurrent->getEndKey();
else
readBegin = rangeBegin;
vCurrent = view.lower_bound(readBegin);
ASSERT(!vCurrent || vCurrent.key() >= readBegin);
if (vCurrent) {
auto b = vCurrent;
--b;
ASSERT(!b || b.key() < readBegin);
}
accumulatedBytes = 0;
while (vCurrent && vCurrent.key() < rangeEnd && limit > 0 && accumulatedBytes < *pLimitBytes) {
if (!vCurrent->isClearTo()) {
result.data.push_back_deep(result.arena, KeyValueRef(vCurrent.key(), vCurrent->getValue()));
accumulatedBytes += sizeof(KeyValueRef) + result.data.end()[-1].expectedSize();
--limit;
}
++vCurrent;
}
} else { // reverse readRange
vCurrent = view.lastLess(rangeEnd);
// A clear might extend all the way to range.end
if (vCurrent && vCurrent->isClearTo() && vCurrent->getEndKey() >= rangeEnd) {
readEnd = vCurrent.key();
--vCurrent;
} else {
readEnd = rangeEnd;
}
ASSERT(!vCurrent || vCurrent.key() < readEnd);
if (vCurrent) {
auto b = vCurrent;
--b;
ASSERT(!b || b.key() >= readEnd);
}
accumulatedBytes = 0;
while (vCurrent && vCurrent.key() >= rangeEnd && limit > 0 && accumulatedBytes < *pLimitBytes) {
if (!vCurrent->isClearTo()) {
result.data.push_back_deep(result.arena, KeyValueRef(vCurrent.key(), vCurrent->getValue()));
accumulatedBytes += sizeof(KeyValueRef) + result.data.end()[-1].expectedSize();
--limit;
}
--vCurrent;
}
}
*pLimitBytes -= accumulatedBytes;
ASSERT(result.data.size() == 0 || *pLimitBytes + result.data.end()[-1].expectedSize() + sizeof(KeyValueRef) > 0);
result.more = limit == 0 || *pLimitBytes <= 0; // FIXME: Does this have to be exact?
result.version = version;
result.cached = true;
return result;
}
Key findKey(StorageCacheData* data, KeySelectorRef sel, Version version, KeyRange range, int* pOffset)
// Attempts to find the key indicated by sel in the data at version, within range.
// Precondition: selectorInRange(sel, range)
// If it is found, offset is set to 0 and a key is returned which falls inside range.
// If the search would depend on any key outside range OR if the key selector offset is too large (range read returns
// too many bytes), it returns either
// a negative offset and a key in [range.begin, sel.getKey()], indicating the key is (the first key <= returned key) +
// offset, or a positive offset and a key in (sel.getKey(), range.end], indicating the key is (the first key >=
// returned key) + offset-1
// The range passed in to this function should specify a cacheRange. If range.begin is repeatedly not the beginning of
// a cacheRange, then it is possible to get stuck looping here
{
ASSERT(version != latestVersion);
ASSERT(selectorInRange(sel, range) && version >= data->oldestVersion.get());
// Count forward or backward distance items, skipping the first one if it == key and skipEqualKey
bool forward = sel.offset > 0; // If forward, result >= sel.getKey(); else result <= sel.getKey()
int sign = forward ? +1 : -1;
bool skipEqualKey = sel.orEqual == forward;
int distance = forward ? sel.offset : 1 - sel.offset;
// Don't limit the number of bytes if this is a trivial key selector (there will be at most two items returned from
// the read range in this case)
int maxBytes;
if (sel.offset <= 1 && sel.offset >= 0)
maxBytes = std::numeric_limits<int>::max();
else
maxBytes = BUGGIFY ? SERVER_KNOBS->BUGGIFY_LIMIT_BYTES : SERVER_KNOBS->STORAGE_LIMIT_BYTES;
GetKeyValuesReply rep =
readRange(data,
version,
forward ? KeyRangeRef(sel.getKey(), range.end) : KeyRangeRef(range.begin, keyAfter(sel.getKey())),
(distance + skipEqualKey) * sign,
&maxBytes);
bool more = rep.more && rep.data.size() != distance + skipEqualKey;
// If we get only one result in the reverse direction as a result of the data being too large, we could get stuck in
// a loop
if (more && !forward && rep.data.size() == 1) {
TEST(true); // Reverse key selector returned only one result in range read
maxBytes = std::numeric_limits<int>::max();
GetKeyValuesReply rep2 =
readRange(data, version, KeyRangeRef(range.begin, keyAfter(sel.getKey())), -2, &maxBytes);
rep = rep2;
more = rep.more && rep.data.size() != distance + skipEqualKey;
ASSERT(rep.data.size() == 2 || !more);
}
int index = distance - 1;
if (skipEqualKey && rep.data.size() && rep.data[0].key == sel.getKey())
++index;
if (index < rep.data.size()) {
*pOffset = 0;
return rep.data[index].key;
} else {
// FIXME: If range.begin=="" && !forward, return success?
*pOffset = index - rep.data.size() + 1;
if (!forward)
*pOffset = -*pOffset;
if (more) {
TEST(true); // Key selector read range had more results
ASSERT(rep.data.size());
Key returnKey = forward ? keyAfter(rep.data.back().key) : rep.data.back().key;
// This is possible if key/value pairs are very large and only one result is returned on a last less than
// query SOMEDAY: graceful handling of exceptionally sized values
ASSERT(returnKey != sel.getKey());
return returnKey;
} else
return forward ? range.end : range.begin;
}
}
KeyRange getCachedKeyRange(StorageCacheData* data, const KeySelectorRef& sel)
// Returns largest range that is cached on this server and selectorInRange(sel, range) or wrong_shard_server if no such
// range exists
{
auto i = sel.isBackward() ? data->cachedRangeMap.rangeContainingKeyBefore(sel.getKey())
: data->cachedRangeMap.rangeContaining(sel.getKey());
if (i->value()->notAssigned())
throw wrong_shard_server();
else if (!i->value()->isReadable())
throw future_version();
ASSERT(selectorInRange(sel, i->range()));
return i->range();
}
ACTOR Future<Void> getKeyValues(StorageCacheData* data, GetKeyValuesRequest req)
// Throws a wrong_shard_server if the keys in the request or result depend on data outside this server OR if a large
// selector offset prevents all data from being read in one range read
{
state int64_t resultSize = 0;
++data->counters.getRangeQueries;
++data->counters.allQueries;
// printf("\nSCGetKeyValues\n");
//++data->readQueueSizeMetric;
// data->maxQueryQueue = std::max<int>( data->maxQueryQueue, data->counters.allQueries.getValue() -
// data->counters.finishedQueries.getValue());
// Active load balancing runs at a very high priority (to obtain accurate queue lengths)
// so we need to downgrade here
TaskPriority taskType = TaskPriority::DefaultEndpoint;
if (SERVER_KNOBS->FETCH_KEYS_LOWER_PRIORITY && req.isFetchKeys) {
taskType = TaskPriority::FetchKeys;
// } else if (false) {
// // Placeholder for up-prioritizing fetches for important requests
// taskType = TaskPriority::DefaultDelay;
}
wait(delay(0, taskType));
try {
if (req.debugID.present())
g_traceBatch.addEvent("TransactionDebug", req.debugID.get().first(), "storagecache.getKeyValues.Before");
state Version version = wait(waitForVersion(data, req.version));
state uint64_t changeCounter = data->cacheRangeChangeCounter;
state KeyRange cachedKeyRange = getCachedKeyRange(data, req.begin);
if (req.debugID.present())
g_traceBatch.addEvent(
"TransactionDebug", req.debugID.get().first(), "storagecache.getKeyValues.AfterVersion");
//.detail("CacheRangeBegin", cachedKeyRange.begin).detail("CacheRangeEnd", cachedKeyRange.end);
if (!selectorInRange(req.end, cachedKeyRange) &&
!(req.end.isFirstGreaterOrEqual() && req.end.getKey() == cachedKeyRange.end)) {
//TraceEvent(SevDebug, "WrongCacheRangeServer1", data->thisServerID).detail("Begin", req.begin.toString()).detail("End", req.end.toString()).detail("Version", version).
// detail("CacheRangeBegin", cachedKeyRange.begin).detail("CacheRangeEnd", cachedKeyRange.end).detail("In",
// "getKeyValues>checkShardExtents");
throw wrong_shard_server();
}
state int offset1;
state int offset2;
state Key begin = req.begin.isFirstGreaterOrEqual()
? req.begin.getKey()
: findKey(data, req.begin, version, cachedKeyRange, &offset1);
state Key end = req.end.isFirstGreaterOrEqual() ? req.end.getKey()
: findKey(data, req.end, version, cachedKeyRange, &offset2);
if (req.debugID.present())
g_traceBatch.addEvent("TransactionDebug", req.debugID.get().first(), "storagecache.getKeyValues.AfterKeys");
//.detail("Off1",offset1).detail("Off2",offset2).detail("ReqBegin",req.begin.getKey()).detail("ReqEnd",req.end.getKey());
// Offsets of zero indicate begin/end keys in this cachedKeyRange, which obviously means we can answer the query
// An end offset of 1 is also OK because the end key is exclusive, so if the first key of the next
// cachedKeyRange is the end the last actual key returned must be from this cachedKeyRange. A begin offset of 1
// is also OK because then either begin is past end or equal to end (so the result is definitely empty)
if ((offset1 && offset1 != 1) || (offset2 && offset2 != 1)) {
TEST(true); // wrong_cache_server due to offset
// We could detect when offset1 takes us off the beginning of the database or offset2 takes us off the end,
// and return a clipped range rather than an error (since that is what the NativeAPI.getRange will do anyway
// via its "slow path"), but we would have to add some flags to the response to encode whether we went off
// the beginning and the end, since it needs that information.
//TraceEvent(SevDebug, "WrongCacheRangeServer2", data->thisServerID).detail("Begin", req.begin.toString()).detail("End", req.end.toString()).detail("Version", version).
// detail("CacheRangeBegin", cachedKeyRange.begin).detail("CacheRangeEnd", cachedKeyRange.end).detail("In",
// "getKeyValues>checkOffsets"). detail("BeginKey", begin).detail("EndKey", end).detail("BeginOffset",
// offset1).detail("EndOffset", offset2);
throw wrong_shard_server();
}
//TraceEvent(SevDebug, "SCGetKeyValues", data->thisServerID).detail("Begin", req.begin.toString()).detail("End", req.end.toString()).detail("Version", version).
// detail("CacheRangeBegin", cachedKeyRange.begin).detail("CacheRangeEnd", cachedKeyRange.end).detail("In",
//"getKeyValues>checkOffsets"). detail("BeginKey", begin).detail("EndKey", end).detail("BeginOffset",
// offset1).detail("EndOffset", offset2);
if (begin >= end) {
if (req.debugID.present())
g_traceBatch.addEvent("TransactionDebug", req.debugID.get().first(), "storagecache.getKeyValues.Send");
//.detail("Begin",begin).detail("End",end);
GetKeyValuesReply none;
none.version = version;
none.more = false;
data->checkChangeCounter(changeCounter,
KeyRangeRef(std::min<KeyRef>(req.begin.getKey(), req.end.getKey()),
std::max<KeyRef>(req.begin.getKey(), req.end.getKey())));
req.reply.send(none);
} else {
state int remainingLimitBytes = req.limitBytes;
GetKeyValuesReply _r = readRange(data, version, KeyRangeRef(begin, end), req.limit, &remainingLimitBytes);
GetKeyValuesReply r = _r;
if (req.debugID.present())
g_traceBatch.addEvent(
"TransactionDebug", req.debugID.get().first(), "storagecache.getKeyValues.AfterReadRange");
data->checkChangeCounter(
changeCounter,
KeyRangeRef(std::min<KeyRef>(begin, std::min<KeyRef>(req.begin.getKey(), req.end.getKey())),
std::max<KeyRef>(end, std::max<KeyRef>(req.begin.getKey(), req.end.getKey()))));
//.detail("Begin",begin).detail("End",end).detail("SizeOf",r.data.size());
if (EXPENSIVE_VALIDATION) {
for (int i = 0; i < r.data.size(); i++)
ASSERT(r.data[i].key >= begin && r.data[i].key < end);
ASSERT(r.data.size() <= std::abs(req.limit));
}
req.reply.send(r);
resultSize = req.limitBytes - remainingLimitBytes;
data->counters.bytesQueried += resultSize;
data->counters.rowsQueried += r.data.size();
}
} catch (Error& e) {
TraceEvent(SevWarn, "SCGetKeyValuesError", data->thisServerID)
.detail("Code", e.code())
.detail("ReqBegin", req.begin.getKey())
.detail("ReqEnd", req.end.getKey())
.detail("ReqVersion", req.version)
.detail("DataVersion", data->version.get());
if (!canReplyWith(e))
throw;
req.reply.sendError(e);
}
++data->counters.finishedQueries;
return Void();
}
ACTOR Future<Void> getKey(StorageCacheData* data, GetKeyRequest req) {
state int64_t resultSize = 0;
++data->counters.getKeyQueries;
++data->counters.allQueries;
// printf("\nSCGetKey\n");
// Active load balancing runs at a very high priority (to obtain accurate queue lengths)
// so we need to downgrade here
wait(delay(0, TaskPriority::DefaultEndpoint));
try {
state Version version = wait(waitForVersion(data, req.version));
state uint64_t changeCounter = data->cacheRangeChangeCounter;
state KeyRange cachedKeyRange = getCachedKeyRange(data, req.sel);
state int offset;
Key k = findKey(data, req.sel, version, cachedKeyRange, &offset);
data->checkChangeCounter(
changeCounter, KeyRangeRef(std::min<KeyRef>(req.sel.getKey(), k), std::max<KeyRef>(req.sel.getKey(), k)));
KeySelector updated;
if (offset < 0)
updated =
firstGreaterOrEqual(k) +
offset; // first thing on this cacheRange OR (large offset case) smallest key retrieved in range read
else if (offset > 0)
updated =
firstGreaterOrEqual(k) + offset -
1; // first thing on next cacheRange OR (large offset case) keyAfter largest key retrieved in range read
else
updated = KeySelectorRef(k, true, 0); // found
resultSize = k.size();
data->counters.bytesQueried += resultSize;
++data->counters.rowsQueried;
GetKeyReply reply(updated, true);
req.reply.send(reply);
} catch (Error& e) {
// if (e.code() == error_code_wrong_shard_server) TraceEvent("SCWrongCacheRangeServer").detail("In","getKey");
// if (e.code() == error_code_future_version) TraceEvent("SCColdCacheRangeServer").detail("In","getKey");
if (!canReplyWith(e))
throw;
req.reply.sendError(e);
}
++data->counters.finishedQueries;
return Void();
}
#pragma endregion
bool expandMutation(MutationRef& m, StorageCacheData::VersionedData const& data, KeyRef eagerTrustedEnd, Arena& ar) {
// After this function call, m should be copied into an arena immediately (before modifying data, cacheRanges, or
// eager)
if (m.type == MutationRef::ClearRange) {
// Expand the clear
const auto& d = data.atLatest();
// If another clear overlaps the beginning of this one, engulf it
auto i = d.lastLess(m.param1);
if (i && i->isClearTo() && i->getEndKey() >= m.param1)
m.param1 = i.key();
// If another clear overlaps the end of this one, engulf it; otherwise expand
i = d.lastLessOrEqual(m.param2);
if (i && i->isClearTo() && i->getEndKey() >= m.param2) {
m.param2 = i->getEndKey();
} else {
// Expand to the next set or clear (from storage or latestVersion), and if it
// is a clear, engulf it as well
i = d.lower_bound(m.param2);
// TODO check if the following is correct
KeyRef endKey = eagerTrustedEnd;
if (!i || endKey < i.key())
m.param2 = endKey;
else if (i->isClearTo())
m.param2 = i->getEndKey();
else
m.param2 = i.key();
}
} else if (m.type != MutationRef::SetValue && (m.type)) {
Optional<StringRef> oldVal;
auto it = data.atLatest().lastLessOrEqual(m.param1);
if (it != data.atLatest().end() && it->isValue() && it.key() == m.param1)
oldVal = it->getValue();
else if (it != data.atLatest().end() && it->isClearTo() && it->getEndKey() > m.param1) {
TEST(true); // Atomic op right after a clear.
}
switch (m.type) {
case MutationRef::AddValue:
m.param2 = doLittleEndianAdd(oldVal, m.param2, ar);
break;
case MutationRef::And:
m.param2 = doAnd(oldVal, m.param2, ar);
break;
case MutationRef::Or:
m.param2 = doOr(oldVal, m.param2, ar);
break;
case MutationRef::Xor:
m.param2 = doXor(oldVal, m.param2, ar);
break;
case MutationRef::AppendIfFits:
m.param2 = doAppendIfFits(oldVal, m.param2, ar);
break;
case MutationRef::Max:
m.param2 = doMax(oldVal, m.param2, ar);
break;
case MutationRef::Min:
m.param2 = doMin(oldVal, m.param2, ar);
break;
case MutationRef::ByteMin:
m.param2 = doByteMin(oldVal, m.param2, ar);
break;
case MutationRef::ByteMax:
m.param2 = doByteMax(oldVal, m.param2, ar);
break;
case MutationRef::MinV2:
m.param2 = doMinV2(oldVal, m.param2, ar);
break;
case MutationRef::AndV2:
m.param2 = doAndV2(oldVal, m.param2, ar);
break;
case MutationRef::CompareAndClear:
if (oldVal.present() && m.param2 == oldVal.get()) {
m.type = MutationRef::ClearRange;
m.param2 = keyAfter(m.param1, ar);
return expandMutation(m, data, eagerTrustedEnd, ar);
}
return false;
}
m.type = MutationRef::SetValue;
}
return true;
}
// Applies a write mutation (SetValue or ClearRange) to the in-memory versioned data structure
void StorageCacheData::applyMutation(MutationRef const& m, Arena& arena, StorageCacheData::VersionedData& data) {
// m is expected to be in arena already
// Clear split keys are added to arena
if (m.type == MutationRef::SetValue) {
auto prev = data.atLatest().lastLessOrEqual(m.param1);
if (prev && prev->isClearTo() && prev->getEndKey() > m.param1) {
ASSERT(prev.key() <= m.param1);
KeyRef end = prev->getEndKey();
// TODO double check if the insert version of the previous clear needs to be preserved for the "left half",
// insert() invalidates prev, so prev.key() is not safe to pass to it by reference
data.insert(KeyRef(prev.key()),
ValueOrClearToRef::clearTo(m.param1),
prev.insertVersion()); // overwritten by below insert if empty
//TraceEvent(SevDebug, "ApplyMutationClearTo")
//.detail("Key1", prev.key())
//.detail("Key2",m.param1)
//.detail("Version1", prev.insertVersion());
KeyRef nextKey = keyAfter(m.param1, arena);
if (end != nextKey) {
ASSERT(end > nextKey);
// TODO double check if it's okay to let go of the the insert version of the "right half"
// FIXME: This copy is technically an asymptotic problem, definitely a waste of memory (copy of keyAfter
// is a waste, but not asymptotic)
data.insert(nextKey, ValueOrClearToRef::clearTo(KeyRef(arena, end)));
//TraceEvent(SevDebug, "ApplyMutationClearTo2")
//.detail("K1", nextKey)
//.detail("K2", end)
//.detail("V", data.latestVersion);
}
}
data.insert(m.param1, ValueOrClearToRef::value(m.param2));
//TraceEvent(SevDebug, "ApplyMutation")
// .detail("Key", m.param1)
// .detail("Value",m.param2)
// .detail("Version", data.latestVersion);
} else if (m.type == MutationRef::ClearRange) {
data.erase(m.param1, m.param2);
ASSERT(m.param2 > m.param1);
ASSERT(!data.isClearContaining(data.atLatest(), m.param1));
data.insert(m.param1, ValueOrClearToRef::clearTo(m.param2));
//TraceEvent(SevDebug, "ApplyMutationClearTo3")
// .detail("Key21", m.param1)
// .detail("Key22", m.param2)
// .detail("V2", data.latestVersion);
}
}
template <class T>
void addMutation(T& target, Version version, MutationRef const& mutation) {
target.addMutation(version, mutation);
}
template <class T>
void addMutation(Reference<T>& target, Version version, MutationRef const& mutation) {
addMutation(*target, version, mutation);
}
template <class T>
void splitMutation(StorageCacheData* data, KeyRangeMap<T>& map, MutationRef const& m, Version ver) {
if (isSingleKeyMutation((MutationRef::Type)m.type)) {
auto i = map.rangeContaining(m.param1);
if (i->value()) // If this key lies in the cached key-range on this server
data->addMutation(i->range(), ver, m);
} else if (m.type == MutationRef::ClearRange) {
KeyRangeRef mKeys(m.param1, m.param2);
auto r = map.intersectingRanges(mKeys);
for (auto i = r.begin(); i != r.end(); ++i) {
if (i->value()) { // if this sub-range exists on this cache server
KeyRangeRef k = mKeys & i->range();
data->addMutation(i->range(), ver, MutationRef((MutationRef::Type)m.type, k.begin, k.end));
}
}
} else
ASSERT(false); // Unknown mutation type in splitMutations
}
void rollback(StorageCacheData* data, Version rollbackVersion, Version nextVersion) {
TEST(true); // call to cacheRange rollback
// FIXME: enable when debugKeyRange is active
// debugKeyRange("Rollback", rollbackVersion, allKeys);
// FIXME: It's not straightforward to rollback certain versions from the VersionedMap.
// It's doable. But for now, we choose to just throw away this cache role
throw please_reboot();
}
void StorageCacheData::addMutation(KeyRangeRef const& cachedKeyRange, Version version, MutationRef const& mutation) {
MutationRef expanded = mutation;
auto& mLog = addVersionToMutationLog(version);
if (!expandMutation(expanded, data(), cachedKeyRange.end, mLog.arena())) {
return;
}
expanded = addMutationToMutationLog(mLog, expanded);
DEBUG_MUTATION("expandedMutation", version, expanded)
.detail("Begin", cachedKeyRange.begin)
.detail("End", cachedKeyRange.end);
applyMutation(expanded, mLog.arena(), mutableData());
// printf("\nSCUpdate: Printing versioned tree after applying mutation\n");
// mutableData().printTree(version);
}
void removeDataRange(StorageCacheData* sc,
Standalone<VerUpdateRef>& mLV,
KeyRangeMap<Reference<CacheRangeInfo>>& cacheRanges,
KeyRangeRef range) {
// modify the latest version of data to remove all sets and trim all clears to exclude range.
// Add a clear to mLV (mutationLog[data.getLatestVersion()]) that ensures all keys in range are removed from the
// disk when this latest version becomes durable mLV is also modified if necessary to ensure that split clears can
// be forgotten
MutationRef clearRange(MutationRef::ClearRange, range.begin, range.end);
clearRange = sc->addMutationToMutationLog(mLV, clearRange);
auto& data = sc->mutableData();
// Expand the range to the right to include other cacheRanges not in versionedData
for (auto r = cacheRanges.rangeContaining(range.end);
r != cacheRanges.ranges().end() && !r->value()->isInVersionedData();
++r)
range = KeyRangeRef(range.begin, r->end());
auto endClear = data.atLatest().lastLess(range.end);
if (endClear && endClear->isClearTo() && endClear->getEndKey() > range.end) {
// This clear has been bumped up to insertVersion==data.getLatestVersion and needs a corresponding mutation log
// entry to forget
MutationRef m(MutationRef::ClearRange, range.end, endClear->getEndKey());
m = sc->addMutationToMutationLog(mLV, m);
data.insert(m.param1, ValueOrClearToRef::clearTo(m.param2));
}
auto beginClear = data.atLatest().lastLess(range.begin);
if (beginClear && beginClear->isClearTo() && beginClear->getEndKey() > range.begin) {
// We don't need any special mutationLog entry - because the begin key and insert version are unchanged the
// original clear
// mutation works to forget this one - but we need range.begin in the right arena
KeyRef rb(mLV.arena(), range.begin);
// insert() invalidates beginClear, so beginClear.key() is not safe to pass to it by reference
data.insert(KeyRef(beginClear.key()), ValueOrClearToRef::clearTo(rb), beginClear.insertVersion());
}
data.erase(range.begin, range.end);
}
// void setAvailableStatus( StorageServer* self, KeyRangeRef keys, bool available );
// void setAssignedStatus( StorageServer* self, KeyRangeRef keys, bool nowAssigned );
void coalesceCacheRanges(StorageCacheData* data, KeyRangeRef keys) {
auto cacheRanges = data->cachedRangeMap.intersectingRanges(keys);
auto fullRange = data->cachedRangeMap.ranges();
auto iter = cacheRanges.begin();
if (iter != fullRange.begin())
--iter;
auto iterEnd = cacheRanges.end();
if (iterEnd != fullRange.end())
++iterEnd;
bool lastReadable = false;
bool lastNotAssigned = false;
KeyRangeMap<Reference<CacheRangeInfo>>::iterator lastRange;
for (; iter != iterEnd; ++iter) {
if (lastReadable && iter->value()->isReadable()) {
KeyRange range = KeyRangeRef(lastRange->begin(), iter->end());
data->addCacheRange(CacheRangeInfo::newReadWrite(range, data));
iter = data->cachedRangeMap.rangeContaining(range.begin);
} else if (lastNotAssigned && iter->value()->notAssigned()) {
KeyRange range = KeyRangeRef(lastRange->begin(), iter->end());
data->addCacheRange(CacheRangeInfo::newNotAssigned(range));
iter = data->cachedRangeMap.rangeContaining(range.begin);
}
lastReadable = iter->value()->isReadable();
lastNotAssigned = iter->value()->notAssigned();
lastRange = iter;
}
}
ACTOR Future<RangeResult> tryFetchRange(Database cx,
Version version,
KeyRangeRef keys,
GetRangeLimits limits,
bool* isTooOld) {
state Transaction tr(cx);
state RangeResult output;
state KeySelectorRef begin = firstGreaterOrEqual(keys.begin);
state KeySelectorRef end = firstGreaterOrEqual(keys.end);
if (*isTooOld)
throw transaction_too_old();
ASSERT(!cx->switchable);
tr.setVersion(version);
tr.info.taskID = TaskPriority::FetchKeys;
limits.minRows = 0;
try {
loop {
RangeResult rep = wait(tr.getRange(begin, end, limits, true));
limits.decrement(rep);
if (limits.isReached() || !rep.more) {
if (output.size()) {
output.arena().dependsOn(rep.arena());
output.append(output.arena(), rep.begin(), rep.size());
if (limits.isReached() && rep.readThrough.present())
output.readThrough = rep.readThrough.get();
} else {
output = rep;
}
output.more = limits.isReached();
return output;
} else if (rep.readThrough.present()) {
output.arena().dependsOn(rep.arena());
if (rep.size()) {
output.append(output.arena(), rep.begin(), rep.size());
ASSERT(rep.readThrough.get() > rep.end()[-1].key);
} else {
ASSERT(rep.readThrough.get() > keys.begin);
}
begin = firstGreaterOrEqual(rep.readThrough.get());
} else {
output.arena().dependsOn(rep.arena());
output.append(output.arena(), rep.begin(), rep.size());
begin = firstGreaterThan(output.end()[-1].key);
}
}
} catch (Error& e) {
if (begin.getKey() != keys.begin &&
(e.code() == error_code_transaction_too_old || e.code() == error_code_future_version ||
e.code() == error_code_process_behind)) {
if (e.code() == error_code_transaction_too_old)
*isTooOld = true;
output.more = true;
if (begin.isFirstGreaterOrEqual())
output.readThrough = begin.getKey();
return output;
}
throw;
}
}
ACTOR Future<Void> fetchKeys(StorageCacheData* data, AddingCacheRange* cacheRange) {
state TraceInterval interval("SCFetchKeys");
state KeyRange keys = cacheRange->keys;
// state Future<Void> warningLogger = logFetchKeysWarning(cacheRange);
state double startt = now();
// TODO we should probably change this for cache server
state int fetchBlockBytes = BUGGIFY ? SERVER_KNOBS->BUGGIFY_BLOCK_BYTES : SERVER_KNOBS->FETCH_BLOCK_BYTES;
// delay(0) to force a return to the run loop before the work of fetchKeys is started.
// This allows adding->start() to be called inline with CSK.
wait(data->coreStarted.getFuture() && delay(0));
try {
// FIXME: enable when debugKeyRange is active
// debugKeyRange("fetchKeysBegin", data->version.get(), cacheRange->keys);
//TraceEvent(SevDebug, interval.begin(), data->thisServerID)
// .detail("KeyBegin", cacheRange->keys.begin)
// .detail("KeyEnd",cacheRange->keys.end);
validate(data);
// TODO: double check the following block of code!!
// We want to make sure that we can't query below lastAvailable, by waiting for the oldestVersion to become
// lastAvaialble
auto navr = data->newestAvailableVersion.intersectingRanges(keys);
Version lastAvailable = invalidVersion;
for (auto r = navr.begin(); r != navr.end(); ++r) {
ASSERT(r->value() != latestVersion);
lastAvailable = std::max(lastAvailable, r->value());
}
auto ndvr = data->newestDirtyVersion.intersectingRanges(keys);
for (auto r = ndvr.begin(); r != ndvr.end(); ++r)
lastAvailable = std::max(lastAvailable, r->value());
if (lastAvailable != invalidVersion && lastAvailable >= data->oldestVersion.get()) {
TEST(true); // wait for oldest version
wait(data->oldestVersion.whenAtLeast(lastAvailable + 1));
}
TraceEvent(SevDebug, "SCFetchKeysVersionSatisfied", data->thisServerID).detail("FKID", interval.pairID);
wait(data->fetchKeysParallelismLock.take(TaskPriority::DefaultYield, fetchBlockBytes));
state FlowLock::Releaser holdingFKPL(data->fetchKeysParallelismLock, fetchBlockBytes);
// state double executeStart = now();
//++data->counters.fetchWaitingCount;
// data->counters.fetchWaitingMS += 1000*(executeStart - startt);
// Fetch keys gets called while the update actor is processing mutations. data->version will not be updated
// until all mutations for a version have been processed. We need to take the updateVersionLock to ensure
// data->version is greater than the version of the mutation which caused the fetch to be initiated.
wait(data->updateVersionLock.take());
cacheRange->phase = AddingCacheRange::Fetching;
state Version fetchVersion = data->version.get();
data->updateVersionLock.release();
wait(delay(0));
TraceEvent(SevDebug, "SCFetchKeysUnblocked", data->thisServerID)
.detail("FKID", interval.pairID)
.detail("Version", fetchVersion);
// Get the history
state int debug_getRangeRetries = 0;
state int debug_nextRetryToLog = 1;
state bool isTooOld = false;
// FIXME: this should invalidate the location cache for cacheServers
// data->cx->invalidateCache(keys);
loop {
try {
TEST(true); // Fetching keys for transferred cacheRange
state RangeResult this_block =
wait(tryFetchRange(data->cx,
fetchVersion,
keys,
GetRangeLimits(GetRangeLimits::ROW_LIMIT_UNLIMITED, fetchBlockBytes),
&isTooOld));
state int expectedSize =
(int)this_block.expectedSize() + (8 - (int)sizeof(KeyValueRef)) * this_block.size();
TraceEvent(SevDebug, "SCFetchKeysBlock", data->thisServerID)
.detail("FKID", interval.pairID)
.detail("BlockRows", this_block.size())
.detail("BlockBytes", expectedSize)
.detail("KeyBegin", keys.begin)
.detail("KeyEnd", keys.end)
.detail("Last", this_block.size() ? this_block.end()[-1].key : std::string())
.detail("Version", fetchVersion)
.detail("More", this_block.more);
// FIXME: enable when debugKeyRange is active
// debugKeyRange("fetchRange", fetchVersion, keys);
// FIXME: enable when debugMutation is active
// for(auto k = this_block.begin(); k != this_block.end(); ++k) debugMutation("fetch", fetchVersion,
// MutationRef(MutationRef::SetValue, k->key, k->value));
data->counters.bytesFetched += expectedSize;
if (fetchBlockBytes > expectedSize) {
holdingFKPL.release(fetchBlockBytes - expectedSize);
}
// Write this_block to mutationLog and versionedMap
state KeyValueRef* kvItr = this_block.begin();
for (; kvItr != this_block.end(); ++kvItr) {
applyMutation(data->updater,
data,
MutationRef(MutationRef::SetValue, kvItr->key, kvItr->value),
fetchVersion);
data->counters.bytesFetched += expectedSize;
wait(yield());
}
// TODO: If there was more to be fetched and we hit the limit before - possibly a case where data
// doesn't fit on this cache. For now, we can just fail this cache role. In future, we should think
// about evicting some data to make room for the remaining keys
if (this_block.more) {
TraceEvent(SevDebug, "CacheWarmupMoreDataThanLimit", data->thisServerID);
throw please_reboot();
}
this_block = RangeResult();
if (BUGGIFY)
wait(delay(1));
break;
} catch (Error& e) {
TraceEvent("SCFKBlockFail", data->thisServerID)
.error(e, true)
.suppressFor(1.0)
.detail("FKID", interval.pairID);
if (e.code() == error_code_transaction_too_old) {
TEST(true); // A storage server has forgotten the history data we are fetching
Version lastFV = fetchVersion;
fetchVersion = data->version.get();
isTooOld = false;
// Throw away deferred updates from before fetchVersion, since we don't need them to use blocks
// fetched at that version
while (!cacheRange->updates.empty() && cacheRange->updates[0].version <= fetchVersion)
cacheRange->updates.pop_front();
// TODO: NEELAM: what's this for?
// FIXME: remove when we no longer support upgrades from 5.X
if (debug_getRangeRetries >= 100) {
data->cx->enableLocalityLoadBalance = false;
}
debug_getRangeRetries++;
if (debug_nextRetryToLog == debug_getRangeRetries) {
debug_nextRetryToLog += std::min(debug_nextRetryToLog, 1024);
TraceEvent(SevWarn, "SCFetchPast", data->thisServerID)
.detail("TotalAttempts", debug_getRangeRetries)
.detail("FKID", interval.pairID)
.detail("V", lastFV)
.detail("N", fetchVersion)
.detail("E", data->version.get());
}
} else if (e.code() == error_code_future_version || e.code() == error_code_process_behind) {
TEST(true); // fetchKeys got future_version or process_behind, so there must be a huge storage lag
// somewhere. Keep trying.
} else {
throw;
}
wait(delayJittered(FLOW_KNOBS->PREVENT_FAST_SPIN_DELAY));
}
}
// We have completed the fetch and write of the data, now we wait for MVCC window to pass.
// As we have finished this work, we will allow more work to start...
cacheRange->fetchComplete.send(Void());
// TODO revisit the following block of code
//TraceEvent(SevDebug, "SCFKBeforeFinalCommit", data->thisServerID).detail("FKID", interval.pairID).detail("SV", data->storageVersion()).detail("DV", data->durableVersion.get());
// Directly commit()ing the IKVS would interfere with updateStorage, possibly resulting in an incomplete version
// being recovered. Instead we wait for the updateStorage loop to commit something (and consequently also what
// we have written)
// TODO: do we need this kind of wait? we are not going to make anything durable and hence no fear of wrong
// recovery
// wait( data->durableVersion.whenAtLeast( data->storageVersion()+1 ) );
holdingFKPL.release();
//TraceEvent(SevDebug, "SCFKAfterFinalCommit", data->thisServerID).detail("FKID", interval.pairID).detail("SV", data->storageVersion()).detail("DV", data->durableVersion.get());
// Wait to run during pullAsyncData, after a new batch of versions is received from the tlog
Promise<FetchInjectionInfo*> p;
data->readyFetchKeys.push_back(p);
FetchInjectionInfo* batch = wait(p.getFuture());
TraceEvent(SevDebug, "SCFKUpdateBatch", data->thisServerID).detail("FKID", interval.pairID);
cacheRange->phase = AddingCacheRange::Waiting;
// Choose a transferredVersion. This choice and timing ensure that
// * The transferredVersion can be mutated in versionedData
// * The transferredVersion isn't yet committed to storage (so we can write the availability status change)
// * The transferredVersion is <= the version of any of the updates in batch, and if there is an equal version
// its mutations haven't been processed yet
cacheRange->transferredVersion = data->version.get() + 1;
data->mutableData().createNewVersion(cacheRange->transferredVersion);
ASSERT(cacheRange->transferredVersion > data->oldestVersion.get());
ASSERT(cacheRange->transferredVersion == data->data().getLatestVersion());
TraceEvent(SevDebug, "SCFetchKeysHaveData", data->thisServerID)
.detail("FKID", interval.pairID)
.detail("Version", cacheRange->transferredVersion)
.detail("OldestVersion", data->oldestVersion.get());
validate(data);
// Put the updates that were collected during the FinalCommit phase into the batch at the transferredVersion.
// The mutations will come back through AddingCacheRange::addMutations and be applied to versionedMap and
// mutationLog as normal. The lie about their version is acceptable because this cacheRange will never be read
// at versions < transferredVersion
for (auto i = cacheRange->updates.begin(); i != cacheRange->updates.end(); ++i) {
i->version = cacheRange->transferredVersion;
batch->arena.dependsOn(i->arena());
}
int startSize = batch->changes.size();
TEST(startSize); // Adding fetch data to a batch which already has changes
batch->changes.resize(batch->changes.size() + cacheRange->updates.size());
// FIXME: pass the deque back rather than copy the data
std::copy(cacheRange->updates.begin(), cacheRange->updates.end(), batch->changes.begin() + startSize);
Version checkv = cacheRange->transferredVersion;
for (auto b = batch->changes.begin() + startSize; b != batch->changes.end(); ++b) {
ASSERT(b->version >= checkv);
checkv = b->version;
// FIXME: enable when debugMutation is active
// for(auto& m : b->mutations)
// debugMutation("fetchKeysFinalCommitInject", batch->changes[0].version, m);
}
cacheRange->updates.clear();
// TODO: NEELAM: what exactly does it do? Writing some mutations to log. Do we need it for caches?
// setAvailableStatus(data, keys, true); // keys will be available when getLatestVersion()==transferredVersion
// is durable
// Wait for the transferredVersion (and therefore the cacheRange data) to be committed and compacted.
// TODO: double check.
wait(data->oldestVersion.whenAtLeast(cacheRange->transferredVersion));
ASSERT(data->cachedRangeMap[cacheRange->keys.begin]->assigned() &&
data->cachedRangeMap[cacheRange->keys.begin]->keys ==
cacheRange->keys); // We aren't changing whether the cacheRange is assigned
data->newestAvailableVersion.insert(cacheRange->keys, latestVersion);
cacheRange->readWrite.send(Void());
data->addCacheRange(CacheRangeInfo::newReadWrite(cacheRange->keys, data)); // invalidates cacheRange!
coalesceCacheRanges(data, keys);
validate(data);
//++data->counters.fetchExecutingCount;
// data->counters.fetchExecutingMS += 1000*(now() - executeStart);
// TraceEvent(SevDebug, interval.end(), data->thisServerID);
} catch (Error& e) {
// TraceEvent(SevDebug, interval.end(), data->thisServerID).error(e, true).detail("Version", data->version.get());
// TODO define the shuttingDown state of cache server
if (e.code() == error_code_actor_cancelled &&
/* !data->shuttingDown &&*/ cacheRange->phase >= AddingCacheRange::Fetching) {
if (cacheRange->phase < AddingCacheRange::Waiting) {
// TODO Not sure if it's okay to do this here!!
removeDataRange(
data, data->addVersionToMutationLog(data->data().getLatestVersion()), data->cachedRangeMap, keys);
// data->storage.clearRange( keys );
} else {
ASSERT(data->data().getLatestVersion() > data->version.get());
removeDataRange(
data, data->addVersionToMutationLog(data->data().getLatestVersion()), data->cachedRangeMap, keys);
// setAvailableStatus(data, keys, false);
// Prevent another, overlapping fetchKeys from entering the Fetching phase until
// data->data().getLatestVersion() is durable
data->newestDirtyVersion.insert(keys, data->data().getLatestVersion());
}
}
TraceEvent(SevError, "SCFetchKeysError", data->thisServerID)
.error(e)
.detail("Elapsed", now() - startt)
.detail("KeyBegin", keys.begin)
.detail("KeyEnd", keys.end);
if (e.code() != error_code_actor_cancelled)
data->otherError.sendError(e); // Kill the cache server. Are there any recoverable errors?
throw; // goes nowhere
}
return Void();
};
AddingCacheRange::AddingCacheRange(StorageCacheData* server, KeyRangeRef const& keys)
: server(server), keys(keys), transferredVersion(invalidVersion), phase(WaitPrevious) {
fetchClient = fetchKeys(server, this);
}
void AddingCacheRange::addMutation(Version version, MutationRef const& mutation) {
if (mutation.type == mutation.ClearRange) {
ASSERT(keys.begin <= mutation.param1 && mutation.param2 <= keys.end);
} else if (isSingleKeyMutation((MutationRef::Type)mutation.type)) {
ASSERT(keys.contains(mutation.param1));
}
if (phase == WaitPrevious) {
// Updates can be discarded
} else if (phase == Fetching) {
if (!updates.size() || version > updates.end()[-1].version) {
VerUpdateRef v;
v.version = version;
v.isPrivateData = false;
updates.push_back(v);
} else {
ASSERT(version == updates.end()[-1].version);
}
updates.back().mutations.push_back_deep(updates.back().arena(), mutation);
} else if (phase == Waiting) {
server->addMutation(keys, version, mutation);
} else
ASSERT(false);
}
void CacheRangeInfo::addMutation(Version version, MutationRef const& mutation) {
ASSERT((void*)this);
ASSERT(keys.contains(mutation.param1));
if (adding)
adding->addMutation(version, mutation);
else if (readWrite)
readWrite->addMutation(this->keys, version, mutation);
else if (mutation.type != MutationRef::ClearRange) { // TODO NEELAM: ClearRange mutations are ignored (why do we
// even allow them on un-assigned range?)
TraceEvent(SevError, "DeliveredToNotAssigned")
.detail("Version", version)
.detail("Mutation", mutation.toString());
ASSERT(false); // Mutation delivered to notAssigned cacheRange!
}
}
void cacheWarmup(StorageCacheData* data, const KeyRangeRef& keys, bool nowAssigned, Version version) {
ASSERT(!keys.empty());
validate(data);
// FIXME: enable when debugKeyRange is active
// debugKeyRange( nowAssigned ? "KeysAssigned" : "KeysUnassigned", version, keys );
bool isDifferent = false;
auto existingCacheRanges = data->cachedRangeMap.intersectingRanges(keys);
for (auto it = existingCacheRanges.begin(); it != existingCacheRanges.end(); ++it) {
if (nowAssigned != it->value()->assigned()) {
isDifferent = true;
TraceEvent("SCWRangeDifferent", data->thisServerID)
.detail("KeyBegin", it->range().begin)
.detail("KeyEnd", it->range().end);
break;
}
}
if (!isDifferent) {
TraceEvent("SCWShortCircuit", data->thisServerID).detail("KeyBegin", keys.begin).detail("KeyEnd", keys.end);
return;
}
// Save a backup of the CacheRangeInfo references before we start messing with cacheRanges, in order to defer
// fetchKeys cancellation (and its potential call to removeDataRange()) until cacheRanges is again valid
vector<Reference<CacheRangeInfo>> oldCacheRanges;
auto ocr = data->cachedRangeMap.intersectingRanges(keys);
for (auto r = ocr.begin(); r != ocr.end(); ++r)
oldCacheRanges.push_back(r->value());
// As addCacheRange (called below)'s documentation requires, reinitialize any overlapping range(s)
auto ranges = data->cachedRangeMap.getAffectedRangesAfterInsertion(
keys, Reference<CacheRangeInfo>()); // null reference indicates the range being changed
for (int i = 0; i < ranges.size(); i++) {
if (!ranges[i].value) {
ASSERT((KeyRangeRef&)ranges[i] == keys); // there shouldn't be any nulls except for the range being inserted
} else if (ranges[i].value->notAssigned())
data->addCacheRange(CacheRangeInfo::newNotAssigned(ranges[i]));
else if (ranges[i].value->isReadable())
data->addCacheRange(CacheRangeInfo::newReadWrite(ranges[i], data));
else {
ASSERT(ranges[i].value->adding);
data->addCacheRange(CacheRangeInfo::newAdding(data, ranges[i]));
TEST(true); // cacheWarmup reFetchKeys
}
}
// CacheRange state depends on nowAssigned and whether the data is available (actually assigned in memory or on the
// disk) up to the given version. The latter depends on data->newestAvailableVersion, so loop over the ranges of
// that. SOMEDAY: Could this just use cacheRanges? Then we could explicitly do the removeDataRange here when an
// adding/transferred cacheRange is cancelled
auto vr = data->newestAvailableVersion.intersectingRanges(keys);
std::vector<std::pair<KeyRange, Version>> changeNewestAvailable;
std::vector<KeyRange> removeRanges;
for (auto r = vr.begin(); r != vr.end(); ++r) {
KeyRangeRef range = keys & r->range();
bool dataAvailable = r->value() == latestVersion || r->value() >= version;
/*TraceEvent("CSKRange", data->thisServerID)
.detail("KeyBegin", range.begin)
.detail("KeyEnd", range.end)
.detail("Available", dataAvailable)
.detail("NowAssigned", nowAssigned)
.detail("NewestAvailable", r->value())
.detail("CacheRangeState0", data->cachedRangeMap[range.begin]->debugDescribeState());*/
if (!nowAssigned) {
if (dataAvailable) {
ASSERT(r->value() ==
latestVersion); // Not that we care, but this used to be checked instead of dataAvailable
ASSERT(data->mutableData().getLatestVersion() > version);
changeNewestAvailable.emplace_back(range, version);
removeRanges.push_back(range);
}
data->addCacheRange(CacheRangeInfo::newNotAssigned(range));
} else if (!dataAvailable) {
// SOMEDAY: Avoid restarting adding/transferred cacheRanges
if (version == 0) { // bypass fetchkeys; cacheRange is known empty at version 0
changeNewestAvailable.emplace_back(range, latestVersion);
data->addCacheRange(CacheRangeInfo::newReadWrite(range, data));
// setAvailableStatus(data, range, true);
} else {
auto& cacheRange = data->cachedRangeMap[range.begin];
if (!cacheRange->assigned() || cacheRange->keys != range)
data->addCacheRange(CacheRangeInfo::newAdding(data, range));
}
} else {
changeNewestAvailable.emplace_back(range, latestVersion);
data->addCacheRange(CacheRangeInfo::newReadWrite(range, data));
}
}
// Update newestAvailableVersion when a cacheRange becomes (un)available (in a separate loop to avoid invalidating
// vr above)
for (auto r = changeNewestAvailable.begin(); r != changeNewestAvailable.end(); ++r)
data->newestAvailableVersion.insert(r->first, r->second);
// TODO
// if (!nowAssigned)
// data->metrics.notifyNotReadable( keys );
coalesceCacheRanges(data, KeyRangeRef(ranges[0].begin, ranges[ranges.size() - 1].end));
// Now it is OK to do removeDataRanges, directly and through fetchKeys cancellation (and we have to do so before
// validate())
oldCacheRanges.clear();
ranges.clear();
for (auto r = removeRanges.begin(); r != removeRanges.end(); ++r) {
removeDataRange(data, data->addVersionToMutationLog(data->data().getLatestVersion()), data->cachedRangeMap, *r);
// setAvailableStatus(data, *r, false);
}
validate(data);
}
// Helper class for updating the storage cache (i.e. applying mutations)
class StorageCacheUpdater {
public:
StorageCacheUpdater()
: fromVersion(invalidVersion), currentVersion(invalidVersion), processedCacheStartKey(false) {}
StorageCacheUpdater(Version currentVersion)
: fromVersion(currentVersion), currentVersion(currentVersion), processedCacheStartKey(false) {}
void applyMutation(StorageCacheData* data, MutationRef const& m, Version ver) {
//TraceEvent("SCNewVersion", data->thisServerID).detail("VerWas", data->mutableData().latestVersion).detail("ChVer", ver);
if (currentVersion != ver) {
fromVersion = currentVersion;
currentVersion = ver;
data->mutableData().createNewVersion(ver);
}
DEBUG_MUTATION("SCUpdateMutation", ver, m);
if (m.param1.startsWith(systemKeys.end)) {
//TraceEvent("SCPrivateData", data->thisServerID).detail("Mutation", m.toString()).detail("Version", ver);
applyPrivateCacheData(data, m);
} else {
splitMutation(data, data->cachedRangeMap, m, ver);
}
// TODO
if (data->otherError.getFuture().isReady())
data->otherError.getFuture().get();
}
Version currentVersion;
private:
Version fromVersion;
KeyRef cacheStartKey;
bool nowAssigned;
bool processedCacheStartKey;
// Applies private mutations, as the name suggests. It basically establishes the key-ranges
// that this cache server is responsible for
// TODO Revisit during failure handling. Might we loose some private mutations?
void applyPrivateCacheData(StorageCacheData* data, MutationRef const& m) {
//TraceEvent(SevDebug, "SCPrivateCacheMutation", data->thisServerID).detail("Mutation", m);
if (processedCacheStartKey) {
// we expect changes in pairs, [begin,end). This mutation is for end key of the range
ASSERT(m.type == MutationRef::SetValue && m.param1.startsWith(data->ck));
KeyRangeRef keys(cacheStartKey.removePrefix(data->ck), m.param1.removePrefix(data->ck));
// setAssignedStatus( data, keys, nowAssigned );
// data->cachedRangeMap.insert(keys, true);
// fprintf(stderr, "SCPrivateCacheMutation: begin: %s, end: %s\n", printable(keys.begin).c_str(),
// printable(keys.end).c_str());
// Warmup the cache for the newly added key-range
cacheWarmup(data, /*this,*/ keys, nowAssigned, currentVersion - 1);
processedCacheStartKey = false;
} else if (m.type == MutationRef::SetValue && m.param1.startsWith(data->ck)) {
// We expect changes in pairs, [begin,end), This mutation is for start key of the range
cacheStartKey = m.param1;
nowAssigned = m.param2 != serverKeysFalse;
processedCacheStartKey = true;
} else if (m.type == MutationRef::SetValue && m.param1 == lastEpochEndPrivateKey) {
// lastEpochEnd transactions are guaranteed by the master to be alone in their own batch (version)
// That means we don't have to worry about the impact on changeServerKeys
Version rollbackVersion;
BinaryReader br(m.param2, Unversioned());
br >> rollbackVersion;
if (rollbackVersion < fromVersion && rollbackVersion > data->oldestVersion.get()) {
TEST(true); // CacheRangeApplyPrivateData cacheRange rollback
TraceEvent(SevWarn, "Rollback", data->thisServerID)
.detail("FromVersion", fromVersion)
.detail("ToVersion", rollbackVersion)
.detail("AtVersion", currentVersion)
.detail("OldestVersion", data->oldestVersion.get());
rollback(data, rollbackVersion, currentVersion);
}
} else {
TraceEvent(SevWarn, "SCPrivateCacheMutation: Unknown private mutation");
// ASSERT(false); // Unknown private mutation
}
}
};
void applyMutation(StorageCacheUpdater* updater, StorageCacheData* data, MutationRef const& mutation, Version version) {
updater->applyMutation(data, mutation, version);
}
// Compacts the in-memory VersionedMap, i.e. removes versions below the desiredOldestVersion
// TODO revisit if we change the data structure of the VersionedMap
ACTOR Future<Void> compactCache(StorageCacheData* data) {
loop {
// TODO understand this, should we add delay here?
// if (g_network->isSimulated()) {
// double endTime = g_simulator.checkDisabled(format("%s/compactCache",
// data->thisServerID.toString().c_str())); if(endTime > now()) { wait(delay(endTime - now(),
// TaskPriority::CompactCache));
// }
//}
// Wait until the desiredOldestVersion is greater than the current oldestVersion
wait(data->desiredOldestVersion.whenAtLeast(data->oldestVersion.get() + 1));
wait(delay(0, TaskPriority::CompactCache));
// TODO not really in use as of now. may need in some failure cases. Revisit and remove if no plausible use
state Promise<Void> compactionInProgress;
data->compactionInProgress = compactionInProgress.getFuture();
// state Version oldestVersion = data->oldestVersion.get();
state Version desiredVersion = data->desiredOldestVersion.get();
// Call the compaction routine that does the actual work,
//TraceEvent(SevDebug, "SCCompactCache", data->thisServerID).detail("DesiredVersion", desiredVersion);
// TODO It's a synchronous function call as of now. Should it asynch?
data->mutableData().compact(desiredVersion);
Future<Void> finishedForgetting =
data->mutableData().forgetVersionsBeforeAsync(desiredVersion, TaskPriority::CompactCache);
data->oldestVersion.set(desiredVersion);
wait(finishedForgetting);
// TODO how do we yield here? This may not be enough, because compact() does the heavy lifting
// of compating the VersionedMap. We should probably look into per version compaction and then
// we can yield after compacting one version
wait(yield(TaskPriority::CompactCache));
// TODO what flowlock to acquire during compaction?
compactionInProgress.send(Void());
wait(delay(2.0)); // we want to wait at least some small amount of time before
// wait( delay(0, TaskPriority::CompactCache) ); //Setting compactionInProgess could cause the cache server to
// shut down, so delay to check for cancellation
}
}
ACTOR Future<Void> pullAsyncData(StorageCacheData* data) {
state Future<Void> dbInfoChange = Void();
state Reference<ILogSystem::IPeekCursor> cursor;
state Version tagAt = 0;
state double start = now();
state Version ver = invalidVersion;
++data->counters.updateBatches;
loop {
loop {
choose {
when(wait(cursor ? cursor->getMore(TaskPriority::TLogCommit) : Never())) { break; }
when(wait(dbInfoChange)) {
if (data->logSystem) {
cursor = data->logSystem->peekSingle(
data->thisServerID, data->peekVersion, cacheTag, std::vector<std::pair<Version, Tag>>());
} else
cursor = Reference<ILogSystem::IPeekCursor>();
dbInfoChange = data->db->onChange();
}
}
}
try {
// If the popped version is greater than our last version, we need to clear the cache
if (cursor->version().version <= cursor->popped())
throw please_reboot();
data->lastTLogVersion = cursor->getMaxKnownVersion();
data->versionLag = std::max<int64_t>(0, data->lastTLogVersion - data->version.get());
start = now();
wait(data->updateVersionLock.take(TaskPriority::TLogPeekReply, 1));
state FlowLock::Releaser holdingDVL(data->updateVersionLock);
if (now() - start > 0.1)
TraceEvent("SCSlowTakeLock1", data->thisServerID)
.detailf("From", "%016llx", debug_lastLoadBalanceResultEndpointToken)
.detail("Duration", now() - start)
.detail("Version", data->version.get());
state FetchInjectionInfo fii;
state Reference<ILogSystem::IPeekCursor> cloneCursor2;
loop {
state uint64_t changeCounter = data->cacheRangeChangeCounter;
bool epochEnd = false;
bool hasPrivateData = false;
bool firstMutation = true;
bool dbgLastMessageWasProtocol = false;
Reference<ILogSystem::IPeekCursor> cloneCursor1 = cursor->cloneNoMore();
cloneCursor2 = cursor->cloneNoMore();
// TODO cache servers should write the LogProtocolMessage when they are created
// cloneCursor1->setProtocolVersion(data->logProtocol);
cloneCursor1->setProtocolVersion(g_network->protocolVersion());
for (; cloneCursor1->hasMessage(); cloneCursor1->nextMessage()) {
ArenaReader& cloneReader = *cloneCursor1->reader();
if (LogProtocolMessage::isNextIn(cloneReader)) {
LogProtocolMessage lpm;
cloneReader >> lpm;
dbgLastMessageWasProtocol = true;
cloneCursor1->setProtocolVersion(cloneReader.protocolVersion());
} else if (cloneReader.protocolVersion().hasSpanContext() &&
SpanContextMessage::isNextIn(cloneReader)) {
SpanContextMessage scm;
cloneReader >> scm;
} else {
MutationRef msg;
cloneReader >> msg;
if (firstMutation && msg.param1.startsWith(systemKeys.end))
hasPrivateData = true;
firstMutation = false;
if (msg.param1 == lastEpochEndPrivateKey) {
epochEnd = true;
// ASSERT(firstMutation);
ASSERT(dbgLastMessageWasProtocol);
}
dbgLastMessageWasProtocol = false;
}
}
// Any fetchKeys which are ready to transition their cacheRanges to the adding,transferred state do so
// now. If there is an epoch end we skip this step, to increase testability and to prevent inserting a
// version in the middle of a rolled back version range.
while (!hasPrivateData && !epochEnd && !data->readyFetchKeys.empty()) {
auto fk = data->readyFetchKeys.back();
data->readyFetchKeys.pop_back();
fk.send(&fii);
}
if (data->cacheRangeChangeCounter == changeCounter)
break;
// TEST(true); // A fetchKeys completed while we were doing this, so eager might be outdated. Read it
// again.
}
data->debug_inApplyUpdate = true;
if (EXPENSIVE_VALIDATION)
data->data().atLatest().validate();
validate(data);
state bool injectedChanges = false;
state int changeNum = 0;
state int mutationBytes = 0;
for (; changeNum < fii.changes.size(); changeNum++) {
state int mutationNum = 0;
state VerUpdateRef* pUpdate = &fii.changes[changeNum];
for (; mutationNum < pUpdate->mutations.size(); mutationNum++) {
TraceEvent("SCInjectedChanges", data->thisServerID).detail("Version", pUpdate->version);
applyMutation(data->updater, data, pUpdate->mutations[mutationNum], pUpdate->version);
mutationBytes += pUpdate->mutations[mutationNum].totalSize();
injectedChanges = true;
if (false && mutationBytes > SERVER_KNOBS->DESIRED_UPDATE_BYTES) {
mutationBytes = 0;
wait(delay(SERVER_KNOBS->UPDATE_DELAY));
}
}
}
// FIXME: ensure this can only read data from the current version
// cloneCursor2->setProtocolVersion(data->logProtocol);
cloneCursor2->setProtocolVersion(g_network->protocolVersion());
ver = invalidVersion;
// Now process the mutations
for (; cloneCursor2->hasMessage(); cloneCursor2->nextMessage()) {
ArenaReader& reader = *cloneCursor2->reader();
if (cloneCursor2->version().version > ver && cloneCursor2->version().version > data->version.get()) {
++data->counters.updateVersions;
ver = cloneCursor2->version().version;
}
if (LogProtocolMessage::isNextIn(reader)) {
LogProtocolMessage lpm;
reader >> lpm;
// TODO should we store the logProtocol?
data->logProtocol = reader.protocolVersion();
cloneCursor2->setProtocolVersion(data->logProtocol);
} else if (reader.protocolVersion().hasSpanContext() && SpanContextMessage::isNextIn(reader)) {
SpanContextMessage scm;
reader >> scm;
} else {
MutationRef msg;
reader >> msg;
if (ver != invalidVersion) // This change belongs to a version < minVersion
{
applyMutation(data->updater, data, msg, ver);
data->counters.mutationBytes += msg.totalSize();
++data->counters.mutations;
switch (msg.type) {
case MutationRef::SetValue:
++data->counters.setMutations;
break;
case MutationRef::ClearRange:
++data->counters.clearRangeMutations;
break;
case MutationRef::AddValue:
case MutationRef::And:
case MutationRef::AndV2:
case MutationRef::AppendIfFits:
case MutationRef::ByteMax:
case MutationRef::ByteMin:
case MutationRef::Max:
case MutationRef::Min:
case MutationRef::MinV2:
case MutationRef::Or:
case MutationRef::Xor:
case MutationRef::CompareAndClear:
++data->counters.atomicMutations;
break;
}
} else {
TraceEvent(SevError, "DiscardingPeekedData", data->thisServerID)
.detail("Mutation", msg.toString())
.detail("CursorVersion", cloneCursor2->version().version)
.detail("DataVersion", data->version.get());
}
tagAt = cursor->version().version + 1;
}
}
if (ver != invalidVersion) {
data->lastVersionWithData = ver;
} else {
ver = cloneCursor2->version().version - 1;
}
if (injectedChanges)
data->lastVersionWithData = ver;
data->debug_inApplyUpdate = false;
if (ver != invalidVersion && ver > data->version.get()) {
DEBUG_KEY_RANGE("SCUpdate", ver, allKeys);
data->mutableData().createNewVersion(ver);
// TODO what about otherError
if (data->otherError.getFuture().isReady())
data->otherError.getFuture().get();
// TODO may enable these later
// data->noRecentUpdates.set(false);
// data->lastUpdate = now();
data->version.set(ver); // Triggers replies to waiting gets for new version(s)
data->peekVersion = ver + 1;
// TODO double check
// setDataVersion(data->thisServerID, data->version.get());
// TODO what about otherError
if (data->otherError.getFuture().isReady())
data->otherError.getFuture().get();
// we can get rid of versions beyond maxVerionsInMemory at any point. Update the
// desiredOldestVersion and that may invoke the compaction actor
Version maxVersionsInMemory = SERVER_KNOBS->MAX_READ_TRANSACTION_LIFE_VERSIONS;
Version proposedOldestVersion = data->version.get() - maxVersionsInMemory;
proposedOldestVersion = std::max(proposedOldestVersion, data->oldestVersion.get());
data->desiredOldestVersion.set(proposedOldestVersion);
}
validate(data);
data->lastTLogVersion = cloneCursor2->getMaxKnownVersion();
cursor->advanceTo(cloneCursor2->version());
data->versionLag = std::max<int64_t>(0, data->lastTLogVersion - data->version.get());
if (cursor->version().version >= data->lastTLogVersion) {
if (data->behind) {
TraceEvent("StorageCacheNoLongerBehind", data->thisServerID)
.detail("CursorVersion", cursor->version().version)
.detail("TLogVersion", data->lastTLogVersion);
}
data->behind = false;
}
} catch (Error& err) {
state Error e = err;
TraceEvent(SevDebug, "SCUpdateError", data->thisServerID).error(e).backtrace();
if (e.code() == error_code_worker_removed) {
throw please_reboot();
} else {
throw e;
}
}
tagAt = std::max(tagAt, cursor->version().version);
}
}
// Fetch metadata mutation from the database to establish cache ranges and apply them
ACTOR Future<Void> storageCacheStartUpWarmup(StorageCacheData* self) {
state Transaction tr(self->cx);
state Value trueValue = storageCacheValue(std::vector<uint16_t>{ 0 });
state Value falseValue = storageCacheValue(std::vector<uint16_t>{});
state Standalone<MutationRef> privatized;
privatized.type = MutationRef::SetValue;
state Version readVersion;
try {
loop {
tr.setOption(FDBTransactionOptions::READ_LOCK_AWARE);
tr.setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
try {
RangeResult range = wait(tr.getRange(storageCacheKeys, CLIENT_KNOBS->TOO_MANY));
ASSERT(!range.more);
readVersion = tr.getReadVersion().get();
bool currCached = false;
KeyRef begin, end;
for (const auto& kv : range) {
// These booleans have to flip consistently
ASSERT(currCached == (kv.value == falseValue));
if (kv.value == trueValue) {
begin = kv.key;
privatized.param1 = begin.withPrefix(systemKeys.begin, privatized.arena());
privatized.param2 = serverKeysTrue;
//TraceEvent(SevDebug, "SCStartupFetch", self->thisServerID).
// detail("BeginKey", begin.substr(storageCacheKeys.begin.size())).
// detail("ReadVersion", readVersion).detail("DataVersion", self->version.get());
applyMutation(self->updater, self, privatized, readVersion);
currCached = true;
} else {
currCached = false;
end = kv.key;
privatized.param1 = begin.withPrefix(systemKeys.begin, privatized.arena());
privatized.param2 = serverKeysFalse;
//TraceEvent(SevDebug, "SCStartupFetch", self->thisServerID).detail("EndKey", end.substr(storageCacheKeys.begin.size())).
// detail("ReadVersion", readVersion).detail("DataVersion", self->version.get());
applyMutation(self->updater, self, privatized, readVersion);
}
}
self->peekVersion = readVersion + 1;
break;
} catch (Error& e) {
wait(tr.onError(e));
}
}
} catch (Error& e) {
TraceEvent(SevError, "SCStartUpFailed").error(e);
throw;
}
return Void();
}
ACTOR Future<Void> watchInterface(StorageCacheData* self, StorageServerInterface ssi) {
state Transaction tr(self->cx);
state Key storageKey = storageCacheServerKey(ssi.id());
loop {
loop {
tr.setOption(FDBTransactionOptions::LOCK_AWARE);
tr.setOption(FDBTransactionOptions::ACCESS_SYSTEM_KEYS);
try {
Optional<Value> val = wait(tr.get(storageKey));
// This could race with the data distributor trying to remove
// the interface - but this is ok, as we don't need to kill
// ourselves if FailureMonitor marks us as down (this might save
// from unnecessary cache refreshes).
if (!val.present()) {
tr.set(storageKey, storageCacheServerValue(ssi));
wait(tr.commit());
}
break;
} catch (Error& e) {
wait(tr.onError(e));
}
}
wait(delay(5.0));
}
}
ACTOR Future<Void> storageCacheServer(StorageServerInterface ssi, uint16_t id, Reference<AsyncVar<ServerDBInfo>> db) {
state StorageCacheData self(ssi.id(), id, db);
state ActorCollection actors(false);
state Future<Void> dbInfoChange = Void();
state StorageCacheUpdater updater(self.lastVersionWithData);
self.updater = &updater;
//TraceEvent("StorageCache_CacheServerInterface", self.thisServerID).detail("UID", ssi.uniqueID);
// This helps identify the private mutations meant for this cache server
self.ck = cacheKeysPrefixFor(id).withPrefix(systemKeys.begin); // FFFF/02cacheKeys/[this server]/
actors.add(waitFailureServer(ssi.waitFailure.getFuture()));
actors.add(traceCounters("CacheMetrics",
self.thisServerID,
SERVER_KNOBS->STORAGE_LOGGING_DELAY,
&self.counters.cc,
self.thisServerID.toString() + "/CacheMetrics"));
// fetch already cached ranges from the database and apply them before proceeding
wait(storageCacheStartUpWarmup(&self));
// compactCache actor will periodically compact the cache when certain version condition is met
actors.add(compactCache(&self));
// pullAsyncData actor pulls mutations from the TLog and also applies them.
actors.add(pullAsyncData(&self));
actors.add(watchInterface(&self, ssi));
actors.add(traceRole(Role::STORAGE_CACHE, ssi.id()));
self.coreStarted.send(Void());
loop {
++self.counters.loops;
choose {
when(wait(dbInfoChange)) {
dbInfoChange = db->onChange();
self.logSystem = ILogSystem::fromServerDBInfo(self.thisServerID, self.db->get());
}
when(GetValueRequest req = waitNext(ssi.getValue.getFuture())) {
// TODO do we need to add throttling for cache servers? Probably not
// actors.add(self->readGuard(req , getValueQ));
actors.add(getValueQ(&self, req));
}
when(WatchValueRequest req = waitNext(ssi.watchValue.getFuture())) { ASSERT(false); }
when(GetKeyRequest req = waitNext(ssi.getKey.getFuture())) { actors.add(getKey(&self, req)); }
when(GetKeyValuesRequest req = waitNext(ssi.getKeyValues.getFuture())) {
actors.add(getKeyValues(&self, req));
}
when(GetShardStateRequest req = waitNext(ssi.getShardState.getFuture())) { ASSERT(false); }
when(StorageQueuingMetricsRequest req = waitNext(ssi.getQueuingMetrics.getFuture())) { ASSERT(false); }
// when( ReplyPromise<Version> reply = waitNext(ssi.getVersion.getFuture()) ) {
// ASSERT(false);
//}
when(ReplyPromise<KeyValueStoreType> reply = waitNext(ssi.getKeyValueStoreType.getFuture())) {
ASSERT(false);
}
when(wait(actors.getResult())) {}
}
}
}