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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplication
#define LOG_FOR_RECOVERY(level) \
MONGO_LOG_COMPONENT(level, ::mongo::logger::LogComponent::kStorageRecovery)
#include "mongo/platform/basic.h"
#include "mongo/db/repl/replication_recovery.h"
#include "mongo/db/catalog/document_validation.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/repl/apply_ops.h"
#include "mongo/db/repl/oplog_applier_impl.h"
#include "mongo/db/repl/oplog_buffer.h"
#include "mongo/db/repl/replication_consistency_markers_impl.h"
#include "mongo/db/repl/storage_interface.h"
#include "mongo/db/repl/transaction_oplog_application.h"
#include "mongo/db/server_recovery.h"
#include "mongo/db/session.h"
#include "mongo/db/storage/storage_parameters_gen.h"
#include "mongo/db/transaction_history_iterator.h"
#include "mongo/db/transaction_participant.h"
#include "mongo/logv2/log.h"
#include "mongo/util/log.h"
#include "mongo/util/timer.h"
namespace mongo {
namespace repl {
namespace {
const auto kRecoveryBatchLogLevel = logger::LogSeverity::Debug(2);
const auto kRecoveryOperationLogLevel = logger::LogSeverity::Debug(3);
/**
* Tracks and logs operations applied during recovery.
*/
class RecoveryOplogApplierStats : public OplogApplier::Observer {
public:
void onBatchBegin(const std::vector<OplogEntry>& batch) final {
_numBatches++;
LOG_FOR_RECOVERY(kRecoveryBatchLogLevel)
<< "Applying operations in batch: " << _numBatches << "(" << batch.size()
<< " operations from " << batch.front().getOpTime() << " (inclusive) to "
<< batch.back().getOpTime()
<< " (inclusive)). Operations applied so far: " << _numOpsApplied;
_numOpsApplied += batch.size();
if (shouldLog(::mongo::logger::LogComponent::kStorageRecovery,
kRecoveryOperationLogLevel)) {
std::size_t i = 0;
for (const auto& entry : batch) {
i++;
LOG_FOR_RECOVERY(kRecoveryOperationLogLevel)
<< "Applying op " << i << " of " << batch.size() << " (in batch " << _numBatches
<< ") during replication recovery: " << redact(entry.getRaw());
}
}
}
void onBatchEnd(const StatusWith<OpTime>&, const std::vector<OplogEntry>&) final {}
void complete(const OpTime& applyThroughOpTime) const {
LOGV2(21536,
"Applied {numOpsApplied} operations in {numBatches} batches. Last operation applied "
"with optime: {applyThroughOpTime}",
"numOpsApplied"_attr = _numOpsApplied,
"numBatches"_attr = _numBatches,
"applyThroughOpTime"_attr = applyThroughOpTime);
}
private:
std::size_t _numBatches = 0;
std::size_t _numOpsApplied = 0;
};
/**
* OplogBuffer adaptor for a DBClient query on the oplog.
* Implements only functions used by OplogApplier::getNextApplierBatch().
*/
class OplogBufferLocalOplog final : public OplogBuffer {
public:
explicit OplogBufferLocalOplog(Timestamp oplogApplicationStartPoint,
boost::optional<Timestamp> oplogApplicationEndPoint)
: _oplogApplicationStartPoint(oplogApplicationStartPoint),
_oplogApplicationEndPoint(oplogApplicationEndPoint) {}
void startup(OperationContext* opCtx) final {
_client = std::make_unique<DBDirectClient>(opCtx);
BSONObj predicate = _oplogApplicationEndPoint
? BSON("$gte" << _oplogApplicationStartPoint << "$lte" << *_oplogApplicationEndPoint)
: BSON("$gte" << _oplogApplicationStartPoint);
_cursor = _client->query(NamespaceString::kRsOplogNamespace,
QUERY("ts" << predicate),
/*batchSize*/ 0,
/*skip*/ 0,
/*projection*/ nullptr,
QueryOption_OplogReplay);
// Check that the first document matches our appliedThrough point then skip it since it's
// already been applied.
if (!_cursor->more()) {
// This should really be impossible because we check above that the top of the oplog is
// strictly > appliedThrough. If this fails it represents a serious bug in either the
// storage engine or query's implementation of OplogReplay.
std::stringstream ss;
ss << " >= " << _oplogApplicationStartPoint.toBSON();
if (_oplogApplicationEndPoint) {
ss << " and <= " << _oplogApplicationEndPoint->toBSON();
}
LOGV2_FATAL(
21559,
"Couldn't find any entries in the oplog{ss_str}, which should be impossible.",
"ss_str"_attr = ss.str());
fassertFailedNoTrace(40293);
}
auto firstTimestampFound =
fassert(40291, OpTime::parseFromOplogEntry(_cursor->nextSafe())).getTimestamp();
if (firstTimestampFound != _oplogApplicationStartPoint) {
LOGV2_FATAL(21560,
"Oplog entry at {oplogApplicationStartPoint} is missing; actual entry "
"found is {firstTimestampFound}",
"oplogApplicationStartPoint"_attr = _oplogApplicationStartPoint.toBSON(),
"firstTimestampFound"_attr = firstTimestampFound.toBSON());
fassertFailedNoTrace(40292);
}
}
void shutdown(OperationContext*) final {
_cursor = {};
_client = {};
}
bool isEmpty() const final {
return !_cursor->more();
}
bool tryPop(OperationContext*, Value* value) final {
return _peekOrPop(value, Mode::kPop);
}
bool peek(OperationContext*, Value* value) final {
return _peekOrPop(value, Mode::kPeek);
}
void push(OperationContext*, Batch::const_iterator, Batch::const_iterator) final {
MONGO_UNREACHABLE;
}
void waitForSpace(OperationContext*, std::size_t) final {
MONGO_UNREACHABLE;
}
std::size_t getMaxSize() const final {
MONGO_UNREACHABLE;
}
std::size_t getSize() const final {
MONGO_UNREACHABLE;
}
std::size_t getCount() const final {
MONGO_UNREACHABLE;
}
void clear(OperationContext*) final {
MONGO_UNREACHABLE;
}
bool waitForData(Seconds) final {
MONGO_UNREACHABLE;
}
boost::optional<Value> lastObjectPushed(OperationContext*) const final {
MONGO_UNREACHABLE;
}
private:
enum class Mode { kPeek, kPop };
bool _peekOrPop(Value* value, Mode mode) {
if (isEmpty()) {
return false;
}
*value = mode == Mode::kPeek ? _cursor->peekFirst() : _cursor->nextSafe();
invariant(!value->isEmpty());
return true;
}
const Timestamp _oplogApplicationStartPoint;
const boost::optional<Timestamp> _oplogApplicationEndPoint;
std::unique_ptr<DBDirectClient> _client;
std::unique_ptr<DBClientCursor> _cursor;
};
boost::optional<Timestamp> recoverFromOplogPrecursor(OperationContext* opCtx,
StorageInterface* storageInterface) {
if (!storageInterface->supportsRecoveryTimestamp(opCtx->getServiceContext())) {
LOGV2_FATAL(21561,
"Cannot recover from the oplog with a storage engine that does not support "
"recover to stable timestamp.");
fassertFailedNoTrace(50805);
}
// A non-existent recoveryTS means the checkpoint is unstable. If the recoveryTS exists but
// is null, that means a stable checkpoint was taken at a null timestamp. This should never
// happen.
auto recoveryTS = storageInterface->getRecoveryTimestamp(opCtx->getServiceContext());
if (recoveryTS && recoveryTS->isNull()) {
LOGV2_FATAL(21562,
"Cannot recover from the oplog with stable checkpoint at null timestamp.");
fassertFailedNoTrace(50806);
}
return recoveryTS;
}
} // namespace
ReplicationRecoveryImpl::ReplicationRecoveryImpl(StorageInterface* storageInterface,
ReplicationConsistencyMarkers* consistencyMarkers)
: _storageInterface(storageInterface), _consistencyMarkers(consistencyMarkers) {}
void ReplicationRecoveryImpl::_assertNoRecoveryNeededOnUnstableCheckpoint(OperationContext* opCtx) {
invariant(_storageInterface->supportsRecoveryTimestamp(opCtx->getServiceContext()));
invariant(!_storageInterface->getRecoveryTimestamp(opCtx->getServiceContext()));
if (_consistencyMarkers->getInitialSyncFlag(opCtx)) {
LOGV2_FATAL(21563, "Unexpected recovery needed, initial sync flag set.");
fassertFailedNoTrace(31362);
}
const auto truncateAfterPoint = _consistencyMarkers->getOplogTruncateAfterPoint(opCtx);
if (!truncateAfterPoint.isNull()) {
LOGV2_FATAL(21564,
"Unexpected recovery needed, oplog requires truncation. Truncate after point: "
"{truncateAfterPoint}",
"truncateAfterPoint"_attr = truncateAfterPoint.toString());
fassertFailedNoTrace(31363);
}
auto topOfOplogSW = _getTopOfOplog(opCtx);
if (!topOfOplogSW.isOK()) {
LOGV2_FATAL(21565,
"Recovery not possible, no oplog found: {topOfOplogSW_getStatus}",
"topOfOplogSW_getStatus"_attr = topOfOplogSW.getStatus());
fassertFailedNoTrace(31364);
}
const auto topOfOplog = topOfOplogSW.getValue();
const auto appliedThrough = _consistencyMarkers->getAppliedThrough(opCtx);
if (!appliedThrough.isNull() && appliedThrough != topOfOplog) {
LOGV2_FATAL(21566,
"Unexpected recovery needed, appliedThrough is not at top of oplog, indicating "
"oplog has not been fully applied. appliedThrough: {appliedThrough}",
"appliedThrough"_attr = appliedThrough.toString());
fassertFailedNoTrace(31365);
}
const auto minValid = _consistencyMarkers->getMinValid(opCtx);
if (minValid > topOfOplog) {
LOGV2_FATAL(21567,
"Unexpected recovery needed, top of oplog is not consistent. topOfOplog: "
"{topOfOplog}, minValid: {minValid}",
"topOfOplog"_attr = topOfOplog,
"minValid"_attr = minValid);
fassertFailedNoTrace(31366);
}
}
void ReplicationRecoveryImpl::recoverFromOplogAsStandalone(OperationContext* opCtx) {
auto recoveryTS = recoverFromOplogPrecursor(opCtx, _storageInterface);
// Initialize the cached pointer to the oplog collection.
acquireOplogCollectionForLogging(opCtx);
if (recoveryTS) {
// We pass in "none" for the stable timestamp so that recoverFromOplog asks storage
// for the recoveryTimestamp just like on replica set recovery.
const auto stableTimestamp = boost::none;
recoverFromOplog(opCtx, stableTimestamp);
} else {
if (gTakeUnstableCheckpointOnShutdown) {
// Ensure 'recoverFromOplogAsStandalone' with 'takeUnstableCheckpointOnShutdown'
// is safely idempotent when it succeeds.
LOGV2(21537,
"Recovering from unstable checkpoint with 'takeUnstableCheckpointOnShutdown'. "
"Confirming that no oplog recovery is needed.");
_assertNoRecoveryNeededOnUnstableCheckpoint(opCtx);
LOGV2(21538,
"Not doing any oplog recovery since there is an unstable checkpoint that is up "
"to date.");
} else {
LOGV2_FATAL(21568,
"Cannot use 'recoverFromOplogAsStandalone' without a stable checkpoint.");
fassertFailedNoTrace(31229);
}
}
reconstructPreparedTransactions(opCtx, OplogApplication::Mode::kRecovering);
LOGV2_WARNING(21558,
"Setting mongod to readOnly mode as a result of specifying "
"'recoverFromOplogAsStandalone'.");
storageGlobalParams.readOnly = true;
}
void ReplicationRecoveryImpl::recoverFromOplogUpTo(OperationContext* opCtx, Timestamp endPoint) {
uassert(
ErrorCodes::InitialSyncActive,
str::stream() << "Cannot recover from oplog while the node is performing an initial sync",
!_consistencyMarkers->getInitialSyncFlag(opCtx));
auto recoveryTS = recoverFromOplogPrecursor(opCtx, _storageInterface);
if (!recoveryTS) {
LOGV2_FATAL(21569, "Cannot use 'recoverToOplogTimestamp' without a stable checkpoint.");
fassertFailedNoTrace(31399);
}
// This may take an IS lock on the oplog collection.
_truncateOplogIfNeededAndThenClearOplogTruncateAfterPoint(opCtx, recoveryTS);
Timestamp startPoint = _consistencyMarkers->getAppliedThrough(opCtx).getTimestamp();
if (startPoint.isNull()) {
LOGV2(21539, "No stored oplog entries to apply for recovery.");
return;
}
invariant(!endPoint.isNull());
if (startPoint == endPoint) {
LOGV2(21540,
"No oplog entries to apply for recovery. Start point '{startPoint}' is at the end "
"point '{endPoint}' in the oplog.",
"startPoint"_attr = startPoint,
"endPoint"_attr = endPoint);
return;
} else if (startPoint > endPoint) {
uasserted(ErrorCodes::BadValue,
str::stream() << "No oplog entries to apply for recovery. Start point '"
<< startPoint.toString() << "' is beyond the end point '"
<< endPoint.toString() << "' in the oplog.");
}
Timestamp appliedUpTo = _applyOplogOperations(opCtx, startPoint, endPoint);
if (appliedUpTo.isNull()) {
LOGV2(21541,
"No stored oplog entries to apply for recovery between {startPoint} (inclusive) and "
"{endPoint} (inclusive).",
"startPoint"_attr = startPoint.toString(),
"endPoint"_attr = endPoint.toString());
} else {
invariant(appliedUpTo <= endPoint);
}
reconstructPreparedTransactions(opCtx, OplogApplication::Mode::kRecovering);
}
void ReplicationRecoveryImpl::recoverFromOplog(OperationContext* opCtx,
boost::optional<Timestamp> stableTimestamp) try {
if (_consistencyMarkers->getInitialSyncFlag(opCtx)) {
LOGV2(21542, "No recovery needed. Initial sync flag set.");
return; // Initial Sync will take over so no cleanup is needed.
}
const auto serviceCtx = getGlobalServiceContext();
inReplicationRecovery(serviceCtx) = true;
ON_BLOCK_EXIT([serviceCtx] {
invariant(
inReplicationRecovery(serviceCtx),
"replication recovery flag is unexpectedly unset when exiting recoverFromOplog()");
inReplicationRecovery(serviceCtx) = false;
});
// If we were passed in a stable timestamp, we are in rollback recovery and should recover from
// that stable timestamp. Otherwise, we're recovering at startup. If this storage engine
// supports recover to stable timestamp or enableMajorityReadConcern=false, we ask it for the
// recovery timestamp. If the storage engine returns a timestamp, we recover from that point.
// However, if the storage engine returns "none", the storage engine does not have a stable
// checkpoint and we must recover from an unstable checkpoint instead.
const bool supportsRecoveryTimestamp =
_storageInterface->supportsRecoveryTimestamp(opCtx->getServiceContext());
if (!stableTimestamp && supportsRecoveryTimestamp) {
stableTimestamp = _storageInterface->getRecoveryTimestamp(opCtx->getServiceContext());
}
const auto appliedThrough = _consistencyMarkers->getAppliedThrough(opCtx);
invariant(!stableTimestamp || stableTimestamp->isNull() || appliedThrough.isNull() ||
*stableTimestamp == appliedThrough.getTimestamp(),
str::stream() << "Stable timestamp " << stableTimestamp->toString()
<< " does not equal appliedThrough timestamp "
<< appliedThrough.toString());
// This may take an IS lock on the oplog collection.
_truncateOplogIfNeededAndThenClearOplogTruncateAfterPoint(opCtx, stableTimestamp);
auto topOfOplogSW = _getTopOfOplog(opCtx);
if (topOfOplogSW.getStatus() == ErrorCodes::CollectionIsEmpty ||
topOfOplogSW.getStatus() == ErrorCodes::NamespaceNotFound) {
// Oplog is empty. There are no oplog entries to apply, so we exit recovery and go into
// initial sync.
LOGV2(21543, "No oplog entries to apply for recovery. Oplog is empty.");
return;
}
fassert(40290, topOfOplogSW);
const auto topOfOplog = topOfOplogSW.getValue();
if (stableTimestamp) {
invariant(supportsRecoveryTimestamp);
_recoverFromStableTimestamp(opCtx, *stableTimestamp, appliedThrough, topOfOplog);
} else {
_recoverFromUnstableCheckpoint(opCtx, appliedThrough, topOfOplog);
}
} catch (...) {
LOGV2_FATAL(21570,
"Caught exception during replication recovery: {exceptionToStatus}",
"exceptionToStatus"_attr = exceptionToStatus());
std::terminate();
}
void ReplicationRecoveryImpl::_recoverFromStableTimestamp(OperationContext* opCtx,
Timestamp stableTimestamp,
OpTime appliedThrough,
OpTime topOfOplog) {
invariant(!stableTimestamp.isNull());
invariant(!topOfOplog.isNull());
const auto truncateAfterPoint = _consistencyMarkers->getOplogTruncateAfterPoint(opCtx);
LOGV2(21544,
"Recovering from stable timestamp: {stableTimestamp} (top of oplog: {topOfOplog}, "
"appliedThrough: {appliedThrough}, TruncateAfter: {truncateAfterPoint})",
"stableTimestamp"_attr = stableTimestamp,
"topOfOplog"_attr = topOfOplog,
"appliedThrough"_attr = appliedThrough,
"truncateAfterPoint"_attr = truncateAfterPoint);
LOGV2(21545,
"Starting recovery oplog application at the stable timestamp: {stableTimestamp}",
"stableTimestamp"_attr = stableTimestamp);
_applyToEndOfOplog(opCtx, stableTimestamp, topOfOplog.getTimestamp());
}
void ReplicationRecoveryImpl::_recoverFromUnstableCheckpoint(OperationContext* opCtx,
OpTime appliedThrough,
OpTime topOfOplog) {
invariant(!topOfOplog.isNull());
LOGV2(21546,
"Recovering from an unstable checkpoint (top of oplog: {topOfOplog}, appliedThrough: "
"{appliedThrough})",
"topOfOplog"_attr = topOfOplog,
"appliedThrough"_attr = appliedThrough);
if (appliedThrough.isNull()) {
// The appliedThrough would be null if we shut down cleanly or crashed as a primary. Either
// way we are consistent at the top of the oplog.
LOGV2(21547, "No oplog entries to apply for recovery. appliedThrough is null.");
} else {
// If the appliedThrough is not null, then we shut down uncleanly during secondary oplog
// application and must apply from the appliedThrough to the top of the oplog.
LOGV2(21548,
"Starting recovery oplog application at the appliedThrough: {appliedThrough}, "
"through the top of the oplog: {topOfOplog}",
"appliedThrough"_attr = appliedThrough,
"topOfOplog"_attr = topOfOplog);
// When `recoverFromOplog` truncates the oplog, that also happens to set the "oldest
// timestamp" to the truncation point[1]. `_applyToEndOfOplog` will then perform writes
// before the truncation point. Doing so violates the constraint that all updates must be
// timestamped newer than the "oldest timestamp". This call will move the "oldest
// timestamp" back to the `startPoint`.
//
// [1] This is arguably incorrect. On rollback for nodes that are not keeping history to
// the "majority point", the "oldest timestamp" likely needs to go back in time. The
// oplog's `cappedTruncateAfter` method was a convenient location for this logic, which,
// unfortunately, conflicts with the usage above.
opCtx->getServiceContext()->getStorageEngine()->setOldestTimestamp(
appliedThrough.getTimestamp());
_applyToEndOfOplog(opCtx, appliedThrough.getTimestamp(), topOfOplog.getTimestamp());
}
// `_recoverFromUnstableCheckpoint` is only expected to be called on startup.
_storageInterface->setInitialDataTimestamp(opCtx->getServiceContext(),
topOfOplog.getTimestamp());
// Ensure the `appliedThrough` is set to the top of oplog, specifically if the node was
// previously running as a primary. If a crash happens before the first stable checkpoint on
// upgrade, replication recovery will know it must apply from this point and not assume the
// datafiles contain any writes that were taken before the crash.
_consistencyMarkers->setAppliedThrough(opCtx, topOfOplog);
// Force the set `appliedThrough` to become durable on disk in a checkpoint. This method would
// typically take a stable checkpoint, but because we're starting up from a checkpoint that
// has no checkpoint timestamp, the stable checkpoint "degrades" into an unstable checkpoint.
//
// Not waiting for checkpoint durability here can result in a scenario where the node takes
// writes and persists them to the oplog, but crashes before a stable checkpoint persists a
// "recovery timestamp". The typical startup path for data-bearing nodes is to use the recovery
// timestamp to determine where to play oplog forward from. As this method shows, when a
// recovery timestamp does not exist, the applied through is used to determine where to start
// playing oplog entries from.
opCtx->recoveryUnit()->waitUntilUnjournaledWritesDurable(opCtx, /*stableCheckpoint*/ true);
}
void ReplicationRecoveryImpl::_applyToEndOfOplog(OperationContext* opCtx,
const Timestamp& oplogApplicationStartPoint,
const Timestamp& topOfOplog) {
invariant(!oplogApplicationStartPoint.isNull());
invariant(!topOfOplog.isNull());
// Check if we have any unapplied ops in our oplog. It is important that this is done after
// deleting the ragged end of the oplog.
if (oplogApplicationStartPoint == topOfOplog) {
LOGV2(21549,
"No oplog entries to apply for recovery. Start point is at the top of the oplog.");
return; // We've applied all the valid oplog we have.
} else if (oplogApplicationStartPoint > topOfOplog) {
LOGV2_FATAL(
21571,
"Applied op {oplogApplicationStartPoint} not found. Top of oplog is {topOfOplog}.",
"oplogApplicationStartPoint"_attr = oplogApplicationStartPoint.toBSON(),
"topOfOplog"_attr = topOfOplog.toBSON());
fassertFailedNoTrace(40313);
}
Timestamp appliedUpTo = _applyOplogOperations(opCtx, oplogApplicationStartPoint, topOfOplog);
invariant(!appliedUpTo.isNull());
invariant(appliedUpTo == topOfOplog,
str::stream() << "Did not apply to top of oplog. Applied through: "
<< appliedUpTo.toString()
<< ". Top of oplog: " << topOfOplog.toString());
}
Timestamp ReplicationRecoveryImpl::_applyOplogOperations(OperationContext* opCtx,
const Timestamp& startPoint,
const Timestamp& endPoint) {
LOGV2(21550,
"Replaying stored operations from {startPoint} (inclusive) to {endPoint} (inclusive).",
"startPoint"_attr = startPoint,
"endPoint"_attr = endPoint);
OplogBufferLocalOplog oplogBuffer(startPoint, endPoint);
oplogBuffer.startup(opCtx);
RecoveryOplogApplierStats stats;
auto writerPool = makeReplWriterPool();
OplogApplierImpl oplogApplier(nullptr,
&oplogBuffer,
&stats,
ReplicationCoordinator::get(opCtx),
_consistencyMarkers,
_storageInterface,
OplogApplier::Options(OplogApplication::Mode::kRecovering),
writerPool.get());
OplogApplier::BatchLimits batchLimits;
batchLimits.bytes = getBatchLimitOplogBytes(opCtx, _storageInterface);
batchLimits.ops = getBatchLimitOplogEntries();
OpTime applyThroughOpTime;
std::vector<OplogEntry> batch;
while (
!(batch = fassert(50763, oplogApplier.getNextApplierBatch(opCtx, batchLimits))).empty()) {
applyThroughOpTime = uassertStatusOK(oplogApplier.applyOplogBatch(opCtx, std::move(batch)));
}
stats.complete(applyThroughOpTime);
invariant(oplogBuffer.isEmpty(),
str::stream() << "Oplog buffer not empty after applying operations. Last operation "
"applied with optime: "
<< applyThroughOpTime.toBSON());
oplogBuffer.shutdown(opCtx);
// The applied up to timestamp will be null if no oplog entries were applied.
if (applyThroughOpTime.isNull()) {
return Timestamp();
}
// We may crash before setting appliedThrough. If we have a stable checkpoint, we will recover
// to that checkpoint at a replication consistent point, and applying the oplog is safe.
// If we don't have a stable checkpoint, then we must be in startup recovery, and not rollback
// recovery, because we only roll back to a stable timestamp when we have a stable checkpoint.
// Startup recovery from an unstable checkpoint only ever applies a single batch and it is safe
// to replay the batch from any point.
_consistencyMarkers->setAppliedThrough(opCtx, applyThroughOpTime);
return applyThroughOpTime.getTimestamp();
}
StatusWith<OpTime> ReplicationRecoveryImpl::_getTopOfOplog(OperationContext* opCtx) const {
const auto docsSW = _storageInterface->findDocuments(opCtx,
NamespaceString::kRsOplogNamespace,
boost::none, // Collection scan
StorageInterface::ScanDirection::kBackward,
{},
BoundInclusion::kIncludeStartKeyOnly,
1U);
if (!docsSW.isOK()) {
return docsSW.getStatus();
}
const auto docs = docsSW.getValue();
if (docs.empty()) {
return Status(ErrorCodes::CollectionIsEmpty, "oplog is empty");
}
invariant(1U == docs.size());
return OpTime::parseFromOplogEntry(docs.front());
}
void ReplicationRecoveryImpl::_truncateOplogTo(OperationContext* opCtx,
Timestamp truncateAfterTimestamp) {
Timer timer;
// Fetch the oplog collection.
const NamespaceString oplogNss(NamespaceString::kRsOplogNamespace);
AutoGetDb autoDb(opCtx, oplogNss.db(), MODE_IX);
Lock::CollectionLock oplogCollectionLoc(opCtx, oplogNss, MODE_X);
Collection* oplogCollection =
CollectionCatalog::get(opCtx).lookupCollectionByNamespace(opCtx, oplogNss);
if (!oplogCollection) {
fassertFailedWithStatusNoTrace(
34418,
Status(ErrorCodes::NamespaceNotFound,
str::stream() << "Can't find " << NamespaceString::kRsOplogNamespace.ns()));
}
// Find an oplog entry <= truncateAfterTimestamp.
boost::optional<BSONObj> truncateAfterOplogEntryBSON =
_storageInterface->findOplogEntryLessThanOrEqualToTimestamp(
opCtx, oplogCollection, truncateAfterTimestamp);
if (!truncateAfterOplogEntryBSON) {
LOGV2_FATAL(21572,
"Reached end of oplog looking for an oplog entry lte to "
"{truncateAfterTimestamp} but did not find one",
"truncateAfterTimestamp"_attr = truncateAfterTimestamp.toBSON());
fassertFailedNoTrace(40296);
}
// Parse the response.
auto truncateAfterOplogEntry =
fassert(51766, repl::OplogEntry::parse(truncateAfterOplogEntryBSON.get()));
auto truncateAfterRecordId = RecordId(truncateAfterOplogEntry.getTimestamp().asULL());
invariant(truncateAfterRecordId <= RecordId(truncateAfterTimestamp.asULL()),
str::stream() << "Should have found a oplog entry timestamp lte to "
<< truncateAfterTimestamp.toString() << ", but instead found "
<< truncateAfterOplogEntry.toString() << " with timestamp "
<< Timestamp(truncateAfterRecordId.repr()).toString());
// Truncate the oplog AFTER the oplog entry found to be <= truncateAfterTimestamp.
LOGV2(21553,
"Truncating oplog from {truncateAfterOplogEntry_timestamp} (non-inclusive). Truncate "
"after point is {truncateAfterTimestamp}",
"truncateAfterOplogEntry_timestamp"_attr = truncateAfterOplogEntry.getTimestamp(),
"truncateAfterTimestamp"_attr = truncateAfterTimestamp);
oplogCollection->cappedTruncateAfter(opCtx, truncateAfterRecordId, /*inclusive*/ false);
LOGV2(21554,
"Replication recovery oplog truncation finished in: {timer_millis}ms",
"timer_millis"_attr = timer.millis());
}
void ReplicationRecoveryImpl::_truncateOplogIfNeededAndThenClearOplogTruncateAfterPoint(
OperationContext* opCtx, boost::optional<Timestamp> stableTimestamp) {
Timestamp truncatePoint = _consistencyMarkers->getOplogTruncateAfterPoint(opCtx);
if (truncatePoint.isNull()) {
// There are no holes in the oplog that necessitate truncation.
return;
}
if (stableTimestamp && !stableTimestamp->isNull() && truncatePoint <= stableTimestamp) {
AutoGetCollectionForRead oplog(opCtx, NamespaceString::kRsOplogNamespace);
invariant(oplog.getCollection());
LOGV2(21556,
"The oplog truncation point ({truncatePoint}) is equal to or earlier than the stable "
"timestamp ({stableTimestamp_get}), so truncating after the stable timestamp instead",
"truncatePoint"_attr = truncatePoint,
"stableTimestamp_get"_attr = stableTimestamp.get());
truncatePoint = stableTimestamp.get();
}
LOGV2(21557,
"Removing unapplied oplog entries starting after: {truncatePoint}",
"truncatePoint"_attr = truncatePoint.toBSON());
_truncateOplogTo(opCtx, truncatePoint);
// Clear the oplogTruncateAfterPoint now that we have removed any holes that might exist in the
// oplog -- and so that we do not truncate future entries erroneously.
_consistencyMarkers->setOplogTruncateAfterPoint(opCtx, Timestamp());
opCtx->recoveryUnit()->waitUntilDurable(opCtx);
}
} // namespace repl
} // namespace mongo
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