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/**
* Copyright (C) 2013 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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
#include "mongo/platform/basic.h"
#include "mongo/db/write_concern.h"
#include "mongo/base/counter.h"
#include "mongo/bson/util/bson_extract.h"
#include "mongo/db/client.h"
#include "mongo/db/commands/server_status_metric.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/repl/optime.h"
#include "mongo/db/repl/replication_coordinator_global.h"
#include "mongo/db/server_options.h"
#include "mongo/db/service_context.h"
#include "mongo/db/stats/timer_stats.h"
#include "mongo/db/storage/storage_engine.h"
#include "mongo/db/write_concern_options.h"
#include "mongo/rpc/protocol.h"
#include "mongo/util/fail_point_service.h"
#include "mongo/util/log.h"
namespace mongo {
using std::string;
using repl::OpTime;
static TimerStats gleWtimeStats;
static ServerStatusMetricField<TimerStats> displayGleLatency("getLastError.wtime", &gleWtimeStats);
static Counter64 gleWtimeouts;
static ServerStatusMetricField<Counter64> gleWtimeoutsDisplay("getLastError.wtimeouts",
&gleWtimeouts);
MONGO_FP_DECLARE(hangBeforeWaitingForWriteConcern);
bool commandSpecifiesWriteConcern(const BSONObj& cmdObj) {
return cmdObj.hasField(WriteConcernOptions::kWriteConcernField);
}
StatusWith<WriteConcernOptions> extractWriteConcern(OperationContext* opCtx,
const BSONObj& cmdObj,
const std::string& dbName) {
// The default write concern if empty is {w:1}. Specifying {w:0} is/was allowed, but is
// interpreted identically to {w:1}.
auto wcResult = WriteConcernOptions::extractWCFromCommand(
cmdObj, dbName, repl::ReplicationCoordinator::get(opCtx)->getGetLastErrorDefault());
if (!wcResult.isOK()) {
return wcResult.getStatus();
}
WriteConcernOptions writeConcern = wcResult.getValue();
if (writeConcern.usedDefault) {
if (serverGlobalParams.clusterRole == ClusterRole::ConfigServer &&
!opCtx->getClient()->isInDirectClient()) {
// This is here only for backwards compatibility with 3.2 clusters which have commands
// that do not specify write concern when writing to the config server.
writeConcern = {
WriteConcernOptions::kMajority, WriteConcernOptions::SyncMode::UNSET, Seconds(30)};
}
} else {
Status wcStatus = validateWriteConcern(opCtx, writeConcern, dbName);
if (!wcStatus.isOK()) {
return wcStatus;
}
}
return writeConcern;
}
Status validateWriteConcern(OperationContext* opCtx,
const WriteConcernOptions& writeConcern,
StringData dbName) {
if (writeConcern.syncMode == WriteConcernOptions::SyncMode::JOURNAL &&
!opCtx->getServiceContext()->getGlobalStorageEngine()->isDurable()) {
return Status(ErrorCodes::BadValue,
"cannot use 'j' option when a host does not have journaling enabled");
}
const auto replMode = repl::ReplicationCoordinator::get(opCtx)->getReplicationMode();
if (replMode == repl::ReplicationCoordinator::modeNone && writeConcern.wNumNodes > 1) {
return Status(ErrorCodes::BadValue, "cannot use 'w' > 1 when a host is not replicated");
}
if (replMode != repl::ReplicationCoordinator::modeReplSet && !writeConcern.wMode.empty() &&
writeConcern.wMode != WriteConcernOptions::kMajority) {
return Status(ErrorCodes::BadValue,
string("cannot use non-majority 'w' mode ") + writeConcern.wMode +
" when a host is not a member of a replica set");
}
return Status::OK();
}
void WriteConcernResult::appendTo(const WriteConcernOptions& writeConcern,
BSONObjBuilder* result) const {
if (syncMillis >= 0)
result->appendNumber("syncMillis", syncMillis);
if (fsyncFiles >= 0)
result->appendNumber("fsyncFiles", fsyncFiles);
if (wTime >= 0) {
if (wTimedOut)
result->appendNumber("waited", wTime);
else
result->appendNumber("wtime", wTime);
}
if (wTimedOut)
result->appendBool("wtimeout", true);
if (writtenTo.size()) {
BSONArrayBuilder hosts(result->subarrayStart("writtenTo"));
for (size_t i = 0; i < writtenTo.size(); ++i) {
hosts.append(writtenTo[i].toString());
}
} else {
result->appendNull("writtenTo");
}
if (err.empty())
result->appendNull("err");
else
result->append("err", err);
// For ephemeral storage engines, 0 files may be fsynced
invariant(writeConcern.syncMode != WriteConcernOptions::SyncMode::FSYNC ||
(result->asTempObj()["fsyncFiles"].numberLong() >= 0 ||
!result->asTempObj()["waited"].eoo()));
}
Status waitForWriteConcern(OperationContext* opCtx,
const OpTime& replOpTime,
const WriteConcernOptions& writeConcern,
WriteConcernResult* result) {
LOG(2) << "Waiting for write concern. OpTime: " << replOpTime
<< ", write concern: " << writeConcern.toBSON();
auto replCoord = repl::ReplicationCoordinator::get(opCtx);
MONGO_FAIL_POINT_PAUSE_WHILE_SET(hangBeforeWaitingForWriteConcern);
// Next handle blocking on disk
Timer syncTimer;
WriteConcernOptions writeConcernWithPopulatedSyncMode =
replCoord->populateUnsetWriteConcernOptionsSyncMode(writeConcern);
switch (writeConcernWithPopulatedSyncMode.syncMode) {
case WriteConcernOptions::SyncMode::UNSET:
severe() << "Attempting to wait on a WriteConcern with an unset sync option";
fassertFailed(34410);
case WriteConcernOptions::SyncMode::NONE:
break;
case WriteConcernOptions::SyncMode::FSYNC: {
StorageEngine* storageEngine = getGlobalServiceContext()->getGlobalStorageEngine();
if (!storageEngine->isDurable()) {
result->fsyncFiles = storageEngine->flushAllFiles(opCtx, true);
} else {
// We only need to commit the journal if we're durable
opCtx->recoveryUnit()->waitUntilDurable();
}
break;
}
case WriteConcernOptions::SyncMode::JOURNAL:
if (replCoord->getReplicationMode() != repl::ReplicationCoordinator::Mode::modeNone) {
// Wait for ops to become durable then update replication system's
// knowledge of this.
OpTime appliedOpTime = replCoord->getMyLastAppliedOpTime();
opCtx->recoveryUnit()->waitUntilDurable();
replCoord->setMyLastDurableOpTimeForward(appliedOpTime);
} else {
opCtx->recoveryUnit()->waitUntilDurable();
}
break;
}
result->syncMillis = syncTimer.millis();
// Now wait for replication
if (replOpTime.isNull()) {
// no write happened for this client yet
return Status::OK();
}
// needed to avoid incrementing gleWtimeStats SERVER-9005
if (writeConcernWithPopulatedSyncMode.wNumNodes <= 1 &&
writeConcernWithPopulatedSyncMode.wMode.empty()) {
// no desired replication check
return Status::OK();
}
// Replica set stepdowns and gle mode changes are thrown as errors
repl::ReplicationCoordinator::StatusAndDuration replStatus =
replCoord->awaitReplication(opCtx, replOpTime, writeConcernWithPopulatedSyncMode);
if (replStatus.status == ErrorCodes::WriteConcernFailed) {
gleWtimeouts.increment();
result->err = "timeout";
result->wTimedOut = true;
}
// Add stats
result->writtenTo = repl::getGlobalReplicationCoordinator()->getHostsWrittenTo(
replOpTime,
writeConcernWithPopulatedSyncMode.syncMode == WriteConcernOptions::SyncMode::JOURNAL);
gleWtimeStats.recordMillis(durationCount<Milliseconds>(replStatus.duration));
result->wTime = durationCount<Milliseconds>(replStatus.duration);
return replStatus.status;
}
} // namespace mongo
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