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author | Kaloian Manassiev <kaloian.manassiev@mongodb.com> | 2016-07-06 13:54:16 -0400 |
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committer | Kaloian Manassiev <kaloian.manassiev@mongodb.com> | 2016-07-08 17:18:46 -0400 |
commit | 71c38ae1c608e1fa4abd9c8d8642508b87d333e5 (patch) | |
tree | 4462e263bcec66cc2fb898402b29c875f8449e05 /src/mongo/db/read_concern.cpp | |
parent | 8aa68afc0ec5043d13c2d0a131974c0ac6da7e6d (diff) | |
download | mongo-71c38ae1c608e1fa4abd9c8d8642508b87d333e5.tar.gz |
SERVER-24939 Pull read concern extract, check and wait to separate utility
Diffstat (limited to 'src/mongo/db/read_concern.cpp')
-rw-r--r-- | src/mongo/db/read_concern.cpp | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/src/mongo/db/read_concern.cpp b/src/mongo/db/read_concern.cpp new file mode 100644 index 00000000000..f4baada6218 --- /dev/null +++ b/src/mongo/db/read_concern.cpp @@ -0,0 +1,133 @@ +/** + * Copyright (C) 2016 MongoDB 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::kCommand + +#include "mongo/platform/basic.h" + +#include "mongo/db/read_concern.h" + +#include "mongo/base/status.h" +#include "mongo/base/status_with.h" +#include "mongo/db/commands.h" +#include "mongo/db/curop.h" +#include "mongo/db/operation_context.h" +#include "mongo/db/repl/read_concern_args.h" +#include "mongo/db/repl/replication_coordinator.h" +#include "mongo/db/server_options.h" +#include "mongo/db/server_parameters.h" +#include "mongo/util/log.h" + +namespace mongo { +namespace { + +// This is a special flag that allows for testing of snapshot behavior by skipping the replication +// related checks and isolating the storage/query side of snapshotting. +bool testingSnapshotBehaviorInIsolation = false; +ExportedServerParameter<bool, ServerParameterType::kStartupOnly> TestingSnapshotBehaviorInIsolation( + ServerParameterSet::getGlobal(), + "testingSnapshotBehaviorInIsolation", + &testingSnapshotBehaviorInIsolation); + +} // namespace + +StatusWith<repl::ReadConcernArgs> extractReadConcern(OperationContext* txn, + const BSONObj& cmdObj, + bool supportsReadConcern) { + repl::ReadConcernArgs readConcernArgs; + + auto readConcernParseStatus = readConcernArgs.initialize(cmdObj); + if (!readConcernParseStatus.isOK()) { + return readConcernParseStatus; + } + + if (!supportsReadConcern && !readConcernArgs.isEmpty()) { + return {ErrorCodes::InvalidOptions, + str::stream() << "Command does not support read concern"}; + } + + return readConcernArgs; +} + +Status waitForReadConcern(OperationContext* txn, const repl::ReadConcernArgs& readConcernArgs) { + repl::ReplicationCoordinator* const replCoord = repl::ReplicationCoordinator::get(txn); + + // Skip waiting for the OpTime when testing snapshot behavior + if (!testingSnapshotBehaviorInIsolation && !readConcernArgs.isEmpty()) { + Status status = replCoord->waitUntilOpTimeForRead(txn, readConcernArgs); + if (!status.isOK()) { + return status; + } + } + + if ((replCoord->getReplicationMode() == repl::ReplicationCoordinator::Mode::modeReplSet || + testingSnapshotBehaviorInIsolation) && + (readConcernArgs.getLevel() == repl::ReadConcernLevel::kMajorityReadConcern || + readConcernArgs.getLevel() == repl::ReadConcernLevel::kLinearizableReadConcern)) { + // ReadConcern Majority is not supported in ProtocolVersion 0. + if (!testingSnapshotBehaviorInIsolation && !replCoord->isV1ElectionProtocol()) { + return {ErrorCodes::ReadConcernMajorityNotEnabled, + str::stream() << "Replica sets running protocol version 0 do not support " + "readConcern: majority"}; + } + + const int debugLevel = serverGlobalParams.clusterRole == ClusterRole::ConfigServer ? 1 : 2; + + LOG(debugLevel) << "Waiting for 'committed' snapshot to be available for reading: " + << readConcernArgs; + + Status status = txn->recoveryUnit()->setReadFromMajorityCommittedSnapshot(); + + // Wait until a snapshot is available. + while (status == ErrorCodes::ReadConcernMajorityNotAvailableYet) { + LOG(debugLevel) << "Snapshot not available yet."; + replCoord->waitUntilSnapshotCommitted(txn, SnapshotName::min()); + status = txn->recoveryUnit()->setReadFromMajorityCommittedSnapshot(); + } + + if (!status.isOK()) { + return status; + } + + LOG(debugLevel) << "Using 'committed' snapshot: " << CurOp::get(txn)->query(); + } + + if (readConcernArgs.getLevel() == repl::ReadConcernLevel::kLinearizableReadConcern) { + if (!readConcernArgs.getOpTime().isNull()) + return {ErrorCodes::FailedToParse, + "afterOpTime not compatible with linearizable read concern"}; + + if (!replCoord->getMemberState().primary()) + return {ErrorCodes::NotMaster, + "cannot satisfy linearizable read concern on non-primary node"}; + } + + return Status::OK(); +} + +} // namespace mongo |