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/**
* Copyright (C) 2015 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/catalog/apply_ops.h"
#include "mongo/db/client.h"
#include "mongo/db/commands/dbhash.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/curop.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/matcher/extensions_callback_disallow_extensions.h"
#include "mongo/db/matcher/matcher.h"
#include "mongo/db/op_observer.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/db/repl/oplog.h"
#include "mongo/db/repl/replication_coordinator_global.h"
#include "mongo/db/service_context.h"
#include "mongo/util/log.h"
namespace mongo {
Status applyOps(OperationContext* txn,
const std::string& dbName,
const BSONObj& applyOpCmd,
BSONObjBuilder* result) {
// SERVER-4328 todo : is global ok or does this take a long time? i believe multiple
// ns used so locking individually requires more analysis
ScopedTransaction scopedXact(txn, MODE_X);
Lock::GlobalWrite globalWriteLock(txn->lockState());
bool userInitiatedWritesAndNotPrimary = txn->writesAreReplicated() &&
!repl::getGlobalReplicationCoordinator()->canAcceptWritesForDatabase(dbName);
if (userInitiatedWritesAndNotPrimary) {
return Status(ErrorCodes::NotMaster,
str::stream() << "Not primary while applying ops to database " << dbName);
}
bool shouldReplicateWrites = txn->writesAreReplicated();
txn->setReplicatedWrites(false);
BSONObj ops = applyOpCmd.firstElement().Obj();
// Preconditions check reads the database state, so needs to be done locked
if (applyOpCmd["preCondition"].type() == Array) {
BSONObjIterator i(applyOpCmd["preCondition"].Obj());
while (i.more()) {
BSONObj f = i.next().Obj();
DBDirectClient db(txn);
BSONObj realres = db.findOne(f["ns"].String(), f["q"].Obj());
// Apply-ops would never have a $where/$text matcher. Using the "DisallowExtensions"
// callback ensures that parsing will throw an error if $where or $text are found.
Matcher m(f["res"].Obj(), ExtensionsCallbackDisallowExtensions());
if (!m.matches(realres)) {
result->append("got", realres);
result->append("whatFailed", f);
txn->setReplicatedWrites(shouldReplicateWrites);
return Status(ErrorCodes::BadValue, "pre-condition failed");
}
}
}
// apply
int num = 0;
int errors = 0;
BSONObjIterator i(ops);
BSONArrayBuilder ab;
const bool alwaysUpsert =
applyOpCmd.hasField("alwaysUpsert") ? applyOpCmd["alwaysUpsert"].trueValue() : true;
while (i.more()) {
BSONElement e = i.next();
const BSONObj& temp = e.Obj();
// Ignore 'n' operations.
const char* opType = temp["op"].valuestrsafe();
if (*opType == 'n')
continue;
const std::string ns = temp["ns"].String();
// Run operations under a nested lock as a hack to prevent yielding.
//
// The list of operations is supposed to be applied atomically; yielding
// would break atomicity by allowing an interruption or a shutdown to occur
// after only some operations are applied. We are already locked globally
// at this point, so taking a DBLock on the namespace creates a nested lock,
// and yields are disallowed for operations that hold a nested lock.
//
// We do not have a wrapping WriteUnitOfWork so it is possible for a journal
// commit to happen with a subset of ops applied.
// TODO figure out what to do about this.
Lock::GlobalWrite globalWriteLockDisallowTempRelease(txn->lockState());
// Ensures that yielding will not happen (see the comment above).
DEV {
Locker::LockSnapshot lockSnapshot;
invariant(!txn->lockState()->saveLockStateAndUnlock(&lockSnapshot));
};
Status status(ErrorCodes::InternalError, "");
try {
MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
if (*opType == 'c') {
status = repl::applyCommand_inlock(txn, temp);
break;
} else {
OldClientContext ctx(txn, ns);
status = repl::applyOperation_inlock(txn, ctx.db(), temp, alwaysUpsert);
break;
}
}
MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "applyOps", ns);
} catch (const DBException& ex) {
ab.append(false);
result->append("applied", ++num);
result->append("code", ex.getCode());
result->append("errmsg", ex.what());
result->append("results", ab.arr());
return Status(ErrorCodes::UnknownError, "");
}
ab.append(status.isOK());
if (!status.isOK()) {
errors++;
}
num++;
WriteUnitOfWork wuow(txn);
logOpForDbHash(txn, ns.c_str());
wuow.commit();
}
result->append("applied", num);
result->append("results", ab.arr());
txn->setReplicatedWrites(shouldReplicateWrites);
if (txn->writesAreReplicated()) {
// We want this applied atomically on slaves
// so we re-wrap without the pre-condition for speed
std::string tempNS = str::stream() << dbName << ".$cmd";
// TODO: possibly use mutable BSON to remove preCondition field
// once it is available
BSONObjBuilder cmdBuilder;
for (auto elem : applyOpCmd) {
auto name = elem.fieldNameStringData();
if (name == "preCondition")
continue;
if (name == "bypassDocumentValidation")
continue;
cmdBuilder.append(elem);
}
const BSONObj cmdRewritten = cmdBuilder.done();
// We currently always logOp the command regardless of whether the individial ops
// succeeded and rely on any failures to also happen on secondaries. This isn't
// perfect, but it's what the command has always done and is part of its "correct"
// behavior.
while (true) {
try {
WriteUnitOfWork wunit(txn);
getGlobalServiceContext()->getOpObserver()->onApplyOps(txn, tempNS, cmdRewritten);
wunit.commit();
break;
} catch (const WriteConflictException& wce) {
LOG(2) << "WriteConflictException while logging applyOps command, retrying.";
txn->recoveryUnit()->abandonSnapshot();
continue;
}
}
}
if (errors != 0) {
return Status(ErrorCodes::UnknownError, "");
}
return Status::OK();
}
} // namespace mongo
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