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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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplicationRollback
#include "mongo/platform/basic.h"
#include "mongo/db/repl/roll_back_local_operations.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/log.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
namespace repl {
// After the release of MongoDB 3.8, these fail point declarations can
// be moved into the rs_rollback.cpp file, as we no longer need to maintain
// functionality for rs_rollback_no_uuid.cpp. See SERVER-29766.
// Failpoint which causes rollback to hang before finishing.
MONGO_FP_DECLARE(rollbackHangBeforeFinish);
// Failpoint which causes rollback to hang and then fail after minValid is written.
MONGO_FP_DECLARE(rollbackHangThenFailAfterWritingMinValid);
// This is needed by rs_rollback and rollback_impl.
MONGO_FP_DECLARE(rollbackHangAfterTransitionToRollback);
namespace {
OpTime getOpTime(const OplogInterface::Iterator::Value& oplogValue) {
return fassertStatusOK(40298, OpTime::parseFromOplogEntry(oplogValue.first));
}
Timestamp getTimestamp(const BSONObj& operation) {
return operation["ts"].timestamp();
}
Timestamp getTimestamp(const OplogInterface::Iterator::Value& oplogValue) {
return getTimestamp(oplogValue.first);
}
long long getHash(const BSONObj& operation) {
return operation["h"].Long();
}
long long getHash(const OplogInterface::Iterator::Value& oplogValue) {
return getHash(oplogValue.first);
}
} // namespace
RollBackLocalOperations::RollBackLocalOperations(const OplogInterface& localOplog,
const RollbackOperationFn& rollbackOperation)
: _localOplogIterator(localOplog.makeIterator()),
_rollbackOperation(rollbackOperation),
_scanned(0) {
uassert(ErrorCodes::BadValue, "invalid local oplog iterator", _localOplogIterator);
uassert(ErrorCodes::BadValue, "null roll back operation function", rollbackOperation);
}
StatusWith<RollBackLocalOperations::RollbackCommonPoint> RollBackLocalOperations::onRemoteOperation(
const BSONObj& operation) {
if (_scanned == 0) {
auto result = _localOplogIterator->next();
if (!result.isOK()) {
return StatusWith<RollbackCommonPoint>(ErrorCodes::OplogStartMissing,
"no oplog during initsync");
}
_localOplogValue = result.getValue();
long long diff = static_cast<long long>(getTimestamp(_localOplogValue).getSecs()) -
getTimestamp(operation).getSecs();
// diff could be positive, negative, or zero
log() << "our last optime: " << getTimestamp(_localOplogValue);
log() << "their last optime: " << getTimestamp(operation);
log() << "diff in end of log times: " << diff << " seconds";
if (diff > 1800) {
severe() << "rollback too long a time period for a rollback.";
return StatusWith<RollbackCommonPoint>(
ErrorCodes::ExceededTimeLimit,
"rollback error: not willing to roll back more than 30 minutes of data");
}
}
while (getTimestamp(_localOplogValue) > getTimestamp(operation)) {
_scanned++;
LOG(2) << "Local oplog entry to roll back: " << redact(_localOplogValue.first);
auto status = _rollbackOperation(_localOplogValue.first);
if (!status.isOK()) {
invariant(ErrorCodes::NoSuchKey != status.code());
return status;
}
auto result = _localOplogIterator->next();
if (!result.isOK()) {
severe() << "rollback error RS101 reached beginning of local oplog";
log() << " scanned: " << _scanned;
log() << " theirTime: " << getTimestamp(operation);
log() << " ourTime: " << getTimestamp(_localOplogValue);
return StatusWith<RollbackCommonPoint>(ErrorCodes::NoMatchingDocument,
"RS101 reached beginning of local oplog [2]");
}
_localOplogValue = result.getValue();
}
if (getTimestamp(_localOplogValue) == getTimestamp(operation)) {
_scanned++;
if (getHash(_localOplogValue) == getHash(operation)) {
return StatusWith<RollbackCommonPoint>(
std::make_pair(getOpTime(_localOplogValue), _localOplogValue.second));
}
LOG(2) << "Local oplog entry to roll back: " << redact(_localOplogValue.first);
auto status = _rollbackOperation(_localOplogValue.first);
if (!status.isOK()) {
invariant(ErrorCodes::NoSuchKey != status.code());
return status;
}
auto result = _localOplogIterator->next();
if (!result.isOK()) {
severe() << "rollback error RS101 reached beginning of local oplog";
log() << " scanned: " << _scanned;
log() << " theirTime: " << getTimestamp(operation);
log() << " ourTime: " << getTimestamp(_localOplogValue);
return StatusWith<RollbackCommonPoint>(ErrorCodes::NoMatchingDocument,
"RS101 reached beginning of local oplog [1]");
}
_localOplogValue = result.getValue();
return StatusWith<RollbackCommonPoint>(
ErrorCodes::NoSuchKey,
"Unable to determine common point - same timestamp but different hash. "
"Need to process additional remote operations.");
}
invariant(getTimestamp(_localOplogValue) < getTimestamp(operation));
_scanned++;
return StatusWith<RollbackCommonPoint>(ErrorCodes::NoSuchKey,
"Unable to determine common point. "
"Need to process additional remote operations.");
}
StatusWith<RollBackLocalOperations::RollbackCommonPoint> syncRollBackLocalOperations(
const OplogInterface& localOplog,
const OplogInterface& remoteOplog,
const RollBackLocalOperations::RollbackOperationFn& rollbackOperation) {
auto remoteIterator = remoteOplog.makeIterator();
auto remoteResult = remoteIterator->next();
if (!remoteResult.isOK()) {
return StatusWith<RollBackLocalOperations::RollbackCommonPoint>(
ErrorCodes::InvalidSyncSource, "remote oplog empty or unreadable");
}
RollBackLocalOperations finder(localOplog, rollbackOperation);
Timestamp theirTime;
while (remoteResult.isOK()) {
theirTime = remoteResult.getValue().first["ts"].timestamp();
BSONObj theirObj = remoteResult.getValue().first;
auto result = finder.onRemoteOperation(theirObj);
if (result.isOK()) {
return result.getValue();
} else if (result.getStatus().code() != ErrorCodes::NoSuchKey) {
return result;
}
remoteResult = remoteIterator->next();
}
severe() << "rollback error RS100 reached beginning of remote oplog";
log() << " them: " << remoteOplog.toString();
log() << " theirTime: " << theirTime;
return StatusWith<RollBackLocalOperations::RollbackCommonPoint>(
ErrorCodes::NoMatchingDocument, "RS100 reached beginning of remote oplog [1]");
}
} // namespace repl
} // namespace mongo
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