mirror of
https://github.com/facebook/rocksdb.git
synced 2024-12-04 20:02:50 +00:00
d010b02e86
Summary: In follow-up to https://github.com/facebook/rocksdb/issues/11922, fix a race in functions like CreateColumnFamily and SetDBOptions where the DB reports one option setting but a different one is left in effect. To fix, we can add an extra mutex around these rare operations. We don't want to hold the DB mutex during I/O or other slow things because of the many purposes it serves, but a mutex more limited to these cases should be fine. I believe this would fix a write-write race in https://github.com/facebook/rocksdb/issues/10079 but not the read-write race. Intended follow-up to this: * Should be able to remove write thread synchronization from DBImpl::WriteOptionsFile Pull Request resolved: https://github.com/facebook/rocksdb/pull/11929 Test Plan: Added two mini-stress style regression tests that fail with >1% probability before this change: DBOptionsTest::SetStatsDumpPeriodSecRace ColumnFamilyTest::CreateAndDropPeriodicRace I haven't reproduced such an inconsistency between in-memory options and on disk latest options, but this change at least improves safety and adds a test anyway: DBOptionsTest::SetStatsDumpPeriodSecRace Reviewed By: ajkr Differential Revision: D50024506 Pulled By: pdillinger fbshipit-source-id: 1e99a9ed4d96fdcf3ac5061ec6b3cee78aecdda4
51 lines
1.3 KiB
C++
51 lines
1.3 KiB
C++
// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
|
|
// This source code is licensed under both the GPLv2 (found in the
|
|
// COPYING file in the root directory) and Apache 2.0 License
|
|
// (found in the LICENSE.Apache file in the root directory).
|
|
|
|
#pragma once
|
|
|
|
#include "rocksdb/rocksdb_namespace.h"
|
|
|
|
// This file declares a wrapper around the efficient folly DistributedMutex
|
|
// that falls back on a standard mutex when not available. See
|
|
// https://github.com/facebook/folly/blob/main/folly/synchronization/DistributedMutex.h
|
|
// for benefits and limitations.
|
|
|
|
// At the moment, only scoped locking is supported using DMutexLock
|
|
// RAII wrapper, because lock/unlock APIs will vary.
|
|
|
|
#ifdef USE_FOLLY
|
|
|
|
#include <folly/synchronization/DistributedMutex.h>
|
|
|
|
namespace ROCKSDB_NAMESPACE {
|
|
|
|
class DMutex : public folly::DistributedMutex {
|
|
public:
|
|
static const char* kName() { return "folly::DistributedMutex"; }
|
|
|
|
explicit DMutex(bool IGNORED_adaptive = false) { (void)IGNORED_adaptive; }
|
|
|
|
// currently no-op
|
|
void AssertHeld() const {}
|
|
};
|
|
using DMutexLock = std::lock_guard<folly::DistributedMutex>;
|
|
|
|
} // namespace ROCKSDB_NAMESPACE
|
|
|
|
#else
|
|
|
|
#include <mutex>
|
|
|
|
#include "port/port.h"
|
|
|
|
namespace ROCKSDB_NAMESPACE {
|
|
|
|
using DMutex = port::Mutex;
|
|
using DMutexLock = std::lock_guard<DMutex>;
|
|
|
|
} // namespace ROCKSDB_NAMESPACE
|
|
|
|
#endif
|