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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/repl/transaction_oplog_application.h"
#include "mongo/db/commands/txn_cmds_gen.h"
#include "mongo/db/repl/apply_ops.h"
#include "mongo/db/session_catalog_mongod.h"
#include "mongo/db/transaction_history_iterator.h"
#include "mongo/db/transaction_participant.h"
namespace mongo {
/**
* Helper that will find the previous oplog entry for that transaction, transform it to be a normal
* applyOps command and applies the oplog entry. Currently used for oplog application of a
* commitTransaction oplog entry during recovery, rollback and initial sync.
*/
Status _applyTransactionFromOplogChain(OperationContext* opCtx,
const repl::OplogEntry& entry,
repl::OplogApplication::Mode mode) {
invariant(mode == repl::OplogApplication::Mode::kRecovering ||
mode == repl::OplogApplication::Mode::kInitialSync);
// Since the TransactionHistoryIterator uses DBDirectClient, it cannot come with snapshot
// isolation.
invariant(!opCtx->recoveryUnit()->getPointInTimeReadTimestamp());
// Get the corresponding prepareTransaction oplog entry.
const auto prepareOpTime = entry.getPrevWriteOpTimeInTransaction();
invariant(prepareOpTime);
TransactionHistoryIterator iter(prepareOpTime.get());
invariant(iter.hasNext());
const auto prepareOplogEntry = iter.next(opCtx);
// Transform prepare command into a normal applyOps command.
const auto prepareCmd = prepareOplogEntry.getOperationToApply().removeField("prepare");
BSONObjBuilder resultWeDontCareAbout;
return applyOps(
opCtx, entry.getNss().db().toString(), prepareCmd, mode, &resultWeDontCareAbout);
}
Status applyCommitTransaction(OperationContext* opCtx,
const repl::OplogEntry& entry,
repl::OplogApplication::Mode mode) {
// Return error if run via applyOps command.
uassert(50987,
"commitTransaction is only used internally by secondaries.",
mode != repl::OplogApplication::Mode::kApplyOpsCmd);
IDLParserErrorContext ctx("commitTransaction");
auto commitCommand = CommitTransactionOplogObject::parse(ctx, entry.getObject());
if (mode == repl::OplogApplication::Mode::kRecovering) {
const auto replCoord = repl::ReplicationCoordinator::get(opCtx);
const auto recoveryTimestamp = replCoord->getRecoveryTimestamp();
invariant(recoveryTimestamp);
// If the commitTimestamp is before the recoveryTimestamp, then the data already
// reflects the operations from the transaction.
const auto& commitTimestamp = commitCommand.getCommitTimestamp();
if (recoveryTimestamp.get() > commitTimestamp) {
return Status::OK();
}
return _applyTransactionFromOplogChain(opCtx, entry, mode);
}
if (mode == repl::OplogApplication::Mode::kInitialSync) {
return _applyTransactionFromOplogChain(opCtx, entry, mode);
}
invariant(mode == repl::OplogApplication::Mode::kSecondary);
// Transaction operations are in its own batch, so we can modify their opCtx.
invariant(entry.getSessionId());
invariant(entry.getTxnNumber());
opCtx->setLogicalSessionId(*entry.getSessionId());
opCtx->setTxnNumber(*entry.getTxnNumber());
// The write on transaction table may be applied concurrently, so refreshing state
// from disk may read that write, causing starting a new transaction on an existing
// txnNumber. Thus, we start a new transaction without refreshing state from disk.
MongoDOperationContextSessionWithoutRefresh sessionCheckout(opCtx);
auto transaction = TransactionParticipant::get(opCtx);
invariant(transaction);
transaction->unstashTransactionResources(opCtx, "commitTransaction");
transaction->commitPreparedTransaction(
opCtx, commitCommand.getCommitTimestamp(), entry.getOpTime());
return Status::OK();
}
Status applyAbortTransaction(OperationContext* opCtx,
const repl::OplogEntry& entry,
repl::OplogApplication::Mode mode) {
// Return error if run via applyOps command.
uassert(50972,
"abortTransaction is only used internally by secondaries.",
mode != repl::OplogApplication::Mode::kApplyOpsCmd);
// We don't put transactions into the prepare state until the end of recovery, so there is
// no transaction to abort.
if (mode == repl::OplogApplication::Mode::kRecovering) {
return Status::OK();
}
// TODO: SERVER-36492 Only run on secondary until we support initial sync.
invariant(mode == repl::OplogApplication::Mode::kSecondary);
// Transaction operations are in its own batch, so we can modify their opCtx.
invariant(entry.getSessionId());
invariant(entry.getTxnNumber());
opCtx->setLogicalSessionId(*entry.getSessionId());
opCtx->setTxnNumber(*entry.getTxnNumber());
// The write on transaction table may be applied concurrently, so refreshing state
// from disk may read that write, causing starting a new transaction on an existing
// txnNumber. Thus, we start a new transaction without refreshing state from disk.
MongoDOperationContextSessionWithoutRefresh sessionCheckout(opCtx);
auto transaction = TransactionParticipant::get(opCtx);
transaction->unstashTransactionResources(opCtx, "abortTransaction");
transaction->abortActiveTransaction(opCtx);
return Status::OK();
}
} // namespace mongo
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