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/**
* Copyright (C) 2019-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::kIndex
#include "mongo/db/catalog/index_timestamp_helper.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/logical_clock.h"
#include "mongo/db/repl/member_state.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/logv2/log.h"
namespace mongo {
namespace {
Status setGhostTimestamp(OperationContext* opCtx, Timestamp timestamp) {
if (auto status = opCtx->recoveryUnit()->setTimestamp(timestamp); !status.isOK()) {
return status;
}
opCtx->recoveryUnit()->setOrderedCommit(false);
auto replCoord = repl::ReplicationCoordinator::get(opCtx);
if (replCoord->isReplEnabled()) {
opCtx->recoveryUnit()->onCommit(
[replCoord](auto commitTime) { replCoord->attemptToAdvanceStableTimestamp(); });
}
return Status::OK();
}
bool requiresGhostCommitTimestampForWrite(OperationContext* opCtx, const NamespaceString& nss) {
if (!nss.isReplicated()) {
return false;
}
auto replCoord = repl::ReplicationCoordinator::get(opCtx);
if (!replCoord->isReplEnabled()) {
return false;
}
if (replCoord->getMemberState().startup2()) {
return false;
}
// Only storage engines that support recover-to-stable need ghost commit timestamps.
if (!opCtx->getServiceContext()->getStorageEngine()->supportsRecoveryTimestamp()) {
return false;
}
return true;
}
} // namespace
void IndexTimestampHelper::setGhostCommitTimestampForWrite(OperationContext* opCtx,
const NamespaceString& nss) {
invariant(opCtx->lockState()->inAWriteUnitOfWork());
if (!requiresGhostCommitTimestampForWrite(opCtx, nss)) {
return;
}
// The lastApplied timestamp is the last OpTime that a node has applied. We choose this
// timestamp on primaries because it is the most recent point-in-time a reader would be able to
// to read at, despite it lagging slighly behind recently committed writes. Because of this lag,
// both on primaries and secondaries, the lastApplied time may be older than any newly committed
// writes. It is therefore required that all callers holding intent locks and wishing to apply
// ghost timestamps also establish a storage engine snapshot for reading that is less than or
// equal to the lastApplied timestamp.
const auto replCoord = repl::ReplicationCoordinator::get(opCtx);
const auto commitTimestamp = replCoord->getMyLastAppliedOpTime().getTimestamp();
const auto mySnapshot = opCtx->recoveryUnit()->getPointInTimeReadTimestamp();
// If a lock that blocks writes is held, there can be no uncommitted writes, so there is no
// need to check snapshot visibility, especially if a caller is not reading with a timestamp.
invariant(mySnapshot || opCtx->lockState()->isCollectionLockedForMode(nss, MODE_S),
"a write-blocking lock is required when applying a ghost timestamp without a read "
"timestamp");
invariant(!mySnapshot || *mySnapshot <= commitTimestamp,
str::stream() << "commit timestamp " << commitTimestamp.toString()
<< " cannot be older than current read timestamp "
<< mySnapshot->toString());
auto status = setGhostTimestamp(opCtx, commitTimestamp);
if (status.code() == ErrorCodes::BadValue) {
LOGV2(20379,
"Temporarily could not apply ghost commit timestamp. {status_reason}",
"status_reason"_attr = status.reason());
throw WriteConflictException();
}
LOGV2_DEBUG(20380,
1,
"assigning ghost commit timestamp: {commitTimestamp}",
"commitTimestamp"_attr = commitTimestamp.toString());
fassert(51053, status);
}
bool IndexTimestampHelper::requiresGhostCommitTimestampForCatalogWrite(OperationContext* opCtx,
NamespaceString nss) {
if (opCtx->writesAreReplicated()) {
return false;
}
if (!nss.isReplicated() || nss.coll().startsWith("tmp.mr.")) {
return false;
}
auto replCoord = repl::ReplicationCoordinator::get(opCtx);
if (!replCoord->isReplEnabled()) {
return false;
}
// If there is a commit timestamp already assigned, there's no need to explicitly assign a
// timestamp. This case covers foreground index builds.
if (!opCtx->recoveryUnit()->getCommitTimestamp().isNull()) {
return false;
}
// Only oplog entries (including a user's `applyOps` command) construct indexes via
// `IndexBuilder`. Nodes in `startup` may not yet have initialized the `LogicalClock`, however
// index builds during startup replication recovery must be timestamped. These index builds
// are foregrounded and timestamp their catalog writes with a "commit timestamp". Nodes in the
// oplog application phase of initial sync (`startup2`) must not timestamp index builds before
// the `initialDataTimestamp`.
const auto memberState = replCoord->getMemberState();
if (memberState.startup() || memberState.startup2()) {
return false;
}
// When in rollback via refetch, it's valid for all writes to be untimestamped. Additionally,
// it's illegal to timestamp a write later than the timestamp associated with the node exiting
// the rollback state. This condition opts for being conservative.
if (!serverGlobalParams.enableMajorityReadConcern && memberState.rollback()) {
return false;
}
return true;
}
bool IndexTimestampHelper::setGhostCommitTimestampForCatalogWrite(OperationContext* opCtx,
const NamespaceString& nss) {
invariant(opCtx->lockState()->inAWriteUnitOfWork());
if (!requiresGhostCommitTimestampForCatalogWrite(opCtx, nss)) {
return false;
}
auto status =
setGhostTimestamp(opCtx, LogicalClock::get(opCtx)->getClusterTime().asTimestamp());
if (status.code() == ErrorCodes::BadValue) {
LOGV2(20381,
"Temporarily could not timestamp the index build commit, retrying. {status_reason}",
"status_reason"_attr = status.reason());
throw WriteConflictException();
}
fassert(50701, status);
return true;
}
} // namespace mongo
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