1
0
Fork 0
arangodb/arangod/RocksDBEngine/RocksDBSettingsManager.cpp

286 lines
9.6 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2017 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Simon Grätzer
/// @author Daniel Larkin-York
////////////////////////////////////////////////////////////////////////////////
#include "RocksDBSettingsManager.h"
#include "ApplicationFeatures/ApplicationServer.h"
#include "Basics/ReadLocker.h"
#include "Basics/StringUtils.h"
#include "Basics/VelocyPackHelper.h"
#include "Basics/WriteLocker.h"
#include "Logger/Logger.h"
#include "RestServer/DatabaseFeature.h"
#include "RocksDBEngine/RocksDBCollection.h"
#include "RocksDBEngine/RocksDBColumnFamily.h"
#include "RocksDBEngine/RocksDBCommon.h"
#include "RocksDBEngine/RocksDBCuckooIndexEstimator.h"
#include "RocksDBEngine/RocksDBEdgeIndex.h"
#include "RocksDBEngine/RocksDBEngine.h"
#include "RocksDBEngine/RocksDBKey.h"
#include "RocksDBEngine/RocksDBKeyBounds.h"
#include "RocksDBEngine/RocksDBRecoveryHelper.h"
#include "RocksDBEngine/RocksDBVPackIndex.h"
#include "RocksDBEngine/RocksDBValue.h"
#include "StorageEngine/EngineSelectorFeature.h"
#include "VocBase/ticks.h"
#include <rocksdb/utilities/transaction_db.h>
#include <rocksdb/utilities/write_batch_with_index.h>
#include <rocksdb/write_batch.h>
#include <velocypack/Iterator.h>
#include <velocypack/Parser.h>
#include <velocypack/Slice.h>
#include <velocypack/velocypack-aliases.h>
namespace {
arangodb::Result writeSettings(rocksdb::WriteBatch& batch, VPackBuilder& b, uint64_t seqNumber) {
using arangodb::EngineSelectorFeature;
using arangodb::Logger;
using arangodb::Result;
using arangodb::RocksDBColumnFamily;
using arangodb::RocksDBKey;
using arangodb::RocksDBSettingsType;
using arangodb::StorageEngine;
// now write global settings
StorageEngine* engine = EngineSelectorFeature::ENGINE;
b.clear();
b.openObject();
b.add("tick", VPackValue(std::to_string(TRI_CurrentTickServer())));
b.add("hlc", VPackValue(std::to_string(TRI_HybridLogicalClock())));
b.add("releasedTick", VPackValue(std::to_string(engine->releasedTick())));
b.add("lastSync", VPackValue(std::to_string(seqNumber)));
b.close();
VPackSlice slice = b.slice();
LOG_TOPIC("f5e34", DEBUG, Logger::ENGINES) << "writing settings: " << slice.toJson();
RocksDBKey key;
key.constructSettingsValue(RocksDBSettingsType::ServerTick);
rocksdb::Slice value(slice.startAs<char>(), slice.byteSize());
rocksdb::Status s = batch.Put(RocksDBColumnFamily::definitions(), key.string(), value);
if (!s.ok()) {
LOG_TOPIC("140ec", WARN, Logger::ENGINES) << "writing settings failed: " << s.ToString();
return arangodb::rocksutils::convertStatus(s);
}
return Result();
}
} // namespace
namespace arangodb {
/// Constructor needs to be called synchrunously,
/// will load counts from the db and scan the WAL
RocksDBSettingsManager::RocksDBSettingsManager(rocksdb::TransactionDB* db)
: _lastSync(0), _syncing(false), _db(db->GetRootDB()), _initialReleasedTick(0) {}
/// retrieve initial values from the database
void RocksDBSettingsManager::retrieveInitialValues() {
loadSettings();
EngineSelectorFeature::ENGINE->releaseTick(_initialReleasedTick);
}
bool RocksDBSettingsManager::lockForSync(bool force) {
if (force) {
while (true) {
bool expected = false;
bool res = _syncing.compare_exchange_strong(expected, true, std::memory_order_acquire,
std::memory_order_relaxed);
if (res) {
break;
}
std::this_thread::sleep_for(std::chrono::milliseconds(10));
}
} else {
bool expected = false;
if (!_syncing.compare_exchange_strong(expected, true, std::memory_order_acquire,
std::memory_order_relaxed)) {
return false;
}
}
return true;
}
/// Thread-Safe force sync
Result RocksDBSettingsManager::sync(bool force) {
TRI_IF_FAILURE("RocksDBSettingsManagerSync") { return Result(); }
if (!_db) {
return Result();
}
if (!lockForSync(force)) {
return Result();
}
// only one thread can enter here at a time
// make sure we give up our lock when we exit this function
auto guard =
scopeGuard([this]() { _syncing.store(false, std::memory_order_release); });
// fetch the seq number prior to any writes; this guarantees that we save
// any subsequent updates in the WAL to replay if we crash in the middle
auto const maxSeqNr = _db->GetLatestSequenceNumber();
auto minSeqNr = maxSeqNr;
rocksdb::TransactionOptions opts;
opts.lock_timeout = 50; // do not wait for locking keys
rocksdb::WriteOptions wo;
rocksdb::WriteBatch batch;
_tmpBuilder.clear(); // recycle our builder
RocksDBEngine* engine = rocksutils::globalRocksEngine();
auto dbfeature = arangodb::DatabaseFeature::DATABASE;
TRI_ASSERT(!engine->inRecovery()); // just don't
bool didWork = false;
auto mappings = engine->collectionMappings();
for (auto const& pair : mappings) {
TRI_voc_tick_t dbid = pair.first;
TRI_voc_cid_t cid = pair.second;
TRI_vocbase_t* vocbase = dbfeature->useDatabase(dbid);
if (!vocbase) {
continue;
}
TRI_ASSERT(!vocbase->isDangling());
TRI_DEFER(vocbase->release());
// intentionally do not `useCollection`, tends to break CI tests
TRI_vocbase_col_status_e status;
std::shared_ptr<LogicalCollection> coll = vocbase->useCollection(cid, status);
if (!coll) {
continue;
}
TRI_DEFER(vocbase->releaseCollection(coll.get()));
LOG_TOPIC("afb17", TRACE, Logger::ENGINES) << "syncing metadata for collection '" << coll->name() << "'";
auto* rcoll = static_cast<RocksDBCollection*>(coll->getPhysical());
rocksdb::SequenceNumber appliedSeq = maxSeqNr;
Result res = rcoll->meta().serializeMeta(batch, *coll, force, _tmpBuilder, appliedSeq);
minSeqNr = std::min(minSeqNr, appliedSeq);
const std::string err = "could not sync metadata for collection '";
if (res.fail()) {
LOG_TOPIC("1038d", WARN, Logger::ENGINES) << err << coll->name() << "'";
return res;
}
if (batch.Count() > 0) {
auto s = _db->Write(wo, &batch);
if (!s.ok()) {
LOG_TOPIC("afa17", WARN, Logger::ENGINES) << err << coll->name() << "'";
return rocksutils::convertStatus(s);
}
didWork = true;
}
batch.Clear();
}
TRI_ASSERT(_lastSync.load() <= minSeqNr);
if (!didWork) {
_lastSync.store(minSeqNr);
return Result(); // nothing was written
}
_tmpBuilder.clear();
Result res = ::writeSettings(batch, _tmpBuilder, std::max(_lastSync.load(), minSeqNr));
if (res.fail()) {
LOG_TOPIC("8a5e6", WARN, Logger::ENGINES)
<< "could not store metadata settings " << res.errorMessage();
return res;
}
// we have to commit all counters in one batch
auto s = _db->Write(wo, &batch);
if (s.ok()) {
_lastSync.store(std::max(_lastSync.load(), minSeqNr));
}
return rocksutils::convertStatus(s);
}
void RocksDBSettingsManager::loadSettings() {
RocksDBKey key;
key.constructSettingsValue(RocksDBSettingsType::ServerTick);
rocksdb::PinnableSlice result;
rocksdb::Status status =
_db->Get(rocksdb::ReadOptions(), RocksDBColumnFamily::definitions(),
key.string(), &result);
if (status.ok()) {
// key may not be there, so don't fail when not found
VPackSlice slice = VPackSlice(reinterpret_cast<uint8_t const*>(result.data()));
TRI_ASSERT(slice.isObject());
LOG_TOPIC("7458b", TRACE, Logger::ENGINES) << "read initial settings: " << slice.toJson();
if (!result.empty()) {
try {
if (slice.hasKey("tick")) {
uint64_t lastTick =
basics::VelocyPackHelper::stringUInt64(slice.get("tick"));
LOG_TOPIC("369d3", TRACE, Logger::ENGINES) << "using last tick: " << lastTick;
TRI_UpdateTickServer(lastTick);
}
if (slice.hasKey("hlc")) {
uint64_t lastHlc =
basics::VelocyPackHelper::stringUInt64(slice.get("hlc"));
LOG_TOPIC("647a8", TRACE, Logger::ENGINES) << "using last hlc: " << lastHlc;
TRI_HybridLogicalClock(lastHlc);
}
if (slice.hasKey("releasedTick")) {
_initialReleasedTick =
basics::VelocyPackHelper::stringUInt64(slice.get("releasedTick"));
LOG_TOPIC("e13f4", TRACE, Logger::ENGINES) << "using released tick: " << _initialReleasedTick;
EngineSelectorFeature::ENGINE->releaseTick(_initialReleasedTick);
}
if (slice.hasKey("lastSync")) {
_lastSync =
basics::VelocyPackHelper::stringUInt64(slice.get("lastSync"));
LOG_TOPIC("9e695", TRACE, Logger::ENGINES) << "last background settings sync: " << _lastSync;
}
} catch (...) {
LOG_TOPIC("1b3de", WARN, Logger::ENGINES)
<< "unable to read initial settings: invalid data";
}
}
}
}
/// earliest safe sequence number to throw away from wal
rocksdb::SequenceNumber RocksDBSettingsManager::earliestSeqNeeded() const {
return _lastSync.load();
}
} // namespace arangodb