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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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/rs_local_client.h"
#include "mongo/db/curop.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/repl/repl_client_info.h"
#include "mongo/db/repl/repl_set_config.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/rpc/unique_message.h"
#include "mongo/util/scopeguard.h"
namespace mongo {
void RSLocalClient::_updateLastOpTimeFromClient(OperationContext* opCtx,
const repl::OpTime& previousOpTimeOnClient) {
const auto lastOpTimeFromClient =
repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
if (lastOpTimeFromClient.isNull() || lastOpTimeFromClient == previousOpTimeOnClient) {
return;
}
stdx::lock_guard<Latch> lk(_mutex);
if (lastOpTimeFromClient >= _lastOpTime) {
// It's always possible for lastOpTimeFromClient to be less than _lastOpTime if another
// thread started and completed a write through this ShardLocal (updating _lastOpTime)
// after this operation had completed its write but before it got here.
_lastOpTime = lastOpTimeFromClient;
}
}
repl::OpTime RSLocalClient::_getLastOpTime() {
stdx::lock_guard<Latch> lk(_mutex);
return _lastOpTime;
}
StatusWith<Shard::CommandResponse> RSLocalClient::runCommandOnce(OperationContext* opCtx,
StringData dbName,
const BSONObj& cmdObj) {
const auto currentOpTimeFromClient =
repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
ON_BLOCK_EXIT([this, &opCtx, ¤tOpTimeFromClient] {
_updateLastOpTimeFromClient(opCtx, currentOpTimeFromClient);
});
try {
DBDirectClient client(opCtx);
rpc::UniqueReply commandResponse =
client.runCommand(OpMsgRequest::fromDBAndBody(dbName, cmdObj));
auto result = commandResponse->getCommandReply().getOwned();
return Shard::CommandResponse(boost::none,
result,
getStatusFromCommandResult(result),
getWriteConcernStatusFromCommandResult(result));
} catch (const DBException& ex) {
return ex.toStatus();
}
}
StatusWith<Shard::QueryResponse> RSLocalClient::queryOnce(
OperationContext* opCtx,
const ReadPreferenceSetting& readPref,
const repl::ReadConcernLevel& readConcernLevel,
const NamespaceString& nss,
const BSONObj& query,
const BSONObj& sort,
boost::optional<long long> limit,
const boost::optional<BSONObj>& hint) {
auto replCoord = repl::ReplicationCoordinator::get(opCtx);
boost::optional<ScopeGuard<std::function<void()>>> readSourceGuard;
if (readConcernLevel == repl::ReadConcernLevel::kMajorityReadConcern) {
// Resets to the original read source at the end of this operation.
auto originalReadSource = opCtx->recoveryUnit()->getTimestampReadSource();
boost::optional<Timestamp> originalReadTimestamp;
if (originalReadSource == RecoveryUnit::ReadSource::kProvided) {
originalReadTimestamp = opCtx->recoveryUnit()->getPointInTimeReadTimestamp(opCtx);
}
readSourceGuard.emplace([opCtx, originalReadSource, originalReadTimestamp] {
if (originalReadSource == RecoveryUnit::ReadSource::kProvided) {
opCtx->recoveryUnit()->setTimestampReadSource(originalReadSource,
originalReadTimestamp);
} else {
opCtx->recoveryUnit()->setTimestampReadSource(originalReadSource);
}
});
// Sets up operation context with majority read snapshot so correct optime can be retrieved.
opCtx->recoveryUnit()->setTimestampReadSource(RecoveryUnit::ReadSource::kMajorityCommitted);
Status status = opCtx->recoveryUnit()->majorityCommittedSnapshotAvailable();
// Waits for any writes performed by this ShardLocal instance to be committed and visible.
Status readConcernStatus = replCoord->waitUntilOpTimeForRead(
opCtx, repl::ReadConcernArgs{_getLastOpTime(), readConcernLevel});
if (!readConcernStatus.isOK()) {
return readConcernStatus;
}
// Informs the storage engine to read from the committed snapshot for the rest of this
// operation.
status = opCtx->recoveryUnit()->majorityCommittedSnapshotAvailable();
if (!status.isOK()) {
return status;
}
} else {
invariant(readConcernLevel == repl::ReadConcernLevel::kLocalReadConcern);
}
DBDirectClient client(opCtx);
FindCommandRequest findRequest{nss};
findRequest.setFilter(query);
if (!sort.isEmpty()) {
findRequest.setSort(sort);
}
if (hint) {
findRequest.setHint(*hint);
}
if (limit) {
findRequest.setLimit(*limit);
}
try {
std::unique_ptr<DBClientCursor> cursor = client.find(std::move(findRequest), readPref);
if (!cursor) {
return {ErrorCodes::OperationFailed,
str::stream() << "Failed to establish a cursor for reading " << nss.ns()
<< " from local storage"};
}
std::vector<BSONObj> documentVector;
while (cursor->more()) {
BSONObj document = cursor->nextSafe().getOwned();
documentVector.push_back(std::move(document));
}
return Shard::QueryResponse{std::move(documentVector),
replCoord->getCurrentCommittedSnapshotOpTime()};
} catch (const DBException& ex) {
return ex.toStatus();
}
}
Status RSLocalClient::runAggregation(
OperationContext* opCtx,
const AggregateCommandRequest& aggRequest,
std::function<bool(const std::vector<BSONObj>& batch,
const boost::optional<BSONObj>& postBatchResumeToken)> callback) {
DBDirectClient client(opCtx);
auto cursor = uassertStatusOKWithContext(
DBClientCursor::fromAggregationRequest(
&client, aggRequest, true /* secondaryOk */, true /* useExhaust */),
"Failed to establish a cursor for aggregation");
while (cursor->more()) {
std::vector<BSONObj> batchDocs;
batchDocs.reserve(cursor->objsLeftInBatch());
while (cursor->moreInCurrentBatch()) {
batchDocs.emplace_back(cursor->nextSafe().getOwned());
}
try {
// TODO SERVER-58938 pass DBClientCursor::_postBatchResumeToken to callback
if (!callback(batchDocs, boost::none)) {
break;
}
} catch (const DBException& ex) {
return ex
.toStatus(str::stream()
<< "Exception while running aggregation retrieval of results callback");
}
}
return Status::OK();
}
} // namespace mongo
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