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rocksdb/db/db_impl/db_impl_debug.cc
Peter Dillinger bb77d17072 Make Flush() optionally wait for OnFlushCompleted (FlushOptions::listener_wait) (#14992)
Summary:
DB::Flush() with wait=true only waits until the flush result is committed (memtables removed from the immutable list). The EventListener::OnFlushCompleted callbacks run afterward, on the background flush thread, with the DB mutex released, and the waiter is only woken by a shared condition variable that many unrelated events also signal. As a result a Flush(wait=true) caller can return before -- or in the middle of -- its OnFlushCompleted callbacks. This surfaced as a flaky failure in the c_test table_filter_listener_metadata case, which asserts listener_state.flush_count == 3 immediately after Flush() returns (https://github.com/facebook/rocksdb/actions/runs/29976431449). It is also long-standing behavior that other tests have worked around with TEST_WaitForBackgroundWork().

This adds an opt-in FlushOptions::listener_wait (default false). When set together with wait=true, Flush() does not return until the OnFlushCompleted callbacks for the flushed memtables have finished. Default behavior is unchanged.

Implementation: MemTableList gains a per-column-family num_pending_flush_notifications_ counter (guarded by the DB mutex). The background flush thread reserves a pending notification at flush-commit time -- before the mutex is released to run the callbacks -- and releases it after they return, in both the single-CF (FlushMemTableToOutputFile) and atomic (AtomicFlushMemTablesToOutputFiles) paths. WaitForFlushMemTables treats a CF as finished only when its normal predicate holds and the counter is zero. Because the memtables are removed and the counter incremented under one continuous mutex hold (and, for atomic flush, all CFs are reserved before the per-CF notify loop starts releasing the mutex), a listener_wait waiter can never observe the flush as finished before the callbacks complete.

The counter is per-CF rather than per-flush, so a listener_wait waiter can wait somewhat longer than strictly necessary: under rapid flushing it may block until an unrelated, later flush's OnFlushCompleted on the same CF also drains (e.g. a waiter satisfied by GetEarliestMemTableID() advancing still waits for the whole CF's pending notifications). This can only over-wait, never return early, and is tolerated in favor of implementation simplicity; a per-memtable-id watermark could tighten it if it ever matters.

To keep the counter balanced against future edits, the release uses an RAII Defer (runs on every exit path) and ~MemTableList asserts the counter has drained to zero; SubPendingFlushNotifications asserts against underflow. A reservation is taken only when a callback will actually fire (committed flush info non-empty, not a mempurge, CF not dropped, listeners registered).

Also adds the C API rocksdb_flushoptions_set/get_listener_wait (regenerated via tools/c_api_gen) and a DBImpl::TEST_FlushMemTableWithListenerWait() helper.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14992

Test Plan:
New db_flush_test cases ListenerWaitWaitsForOnFlushCompleted and ListenerWaitAtomicFlushWaitsForAllOnFlushCompleted use a listener that blocks inside OnFlushCompleted plus spurious bg_cv_ wakeups to deterministically verify that Flush(wait=true, listener_wait=true) does not return until the callback (all CFs, for atomic flush) has finished; the atomic case guards the per-CF mutex-release gap in the notify loop.

Converted existing racy/worked-around cases to the new option: c_test table_filter_listener_metadata, listener_test OnSingleDBFlushTest and MultiDBMultiListeners, and db_flush_test FireOnFlushCompletedAfterCommittedResult (the last previously relied on TEST_WaitForBackgroundWork()). The auto-generated C API roundtrip test covers the new flushoptions field.

db_stress StressTest::TestFlush now sets listener_wait on a hard-coded 1 in 4 of its manual flushes (both the atomic and non-atomic branches), so the crash test exercises the new path with the DbStressListener registered.

Reviewed By: jaykorean

Differential Revision: D113425407

Pulled By: pdillinger

fbshipit-source-id: 6fd0f5bc93fabaccd8010c2fead1d93c4c44ccfb
2026-07-24 09:36:04 -07:00

429 lines
13 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. 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).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef NDEBUG
#include <iostream>
#include <unordered_set>
#include "db/blob/blob_file_cache.h"
#include "db/blob/blob_file_partition_manager.h"
#include "db/column_family.h"
#include "db/db_impl/db_impl.h"
#include "db/error_handler.h"
#include "db/periodic_task_scheduler.h"
#include "monitoring/thread_status_updater.h"
#include "util/cast_util.h"
#include "util/hash_containers.h"
namespace ROCKSDB_NAMESPACE {
uint64_t DBImpl::TEST_GetLevel0TotalSize() {
InstrumentedMutexLock l(&mutex_);
return default_cf_handle_->cfd()->current()->storage_info()->NumLevelBytes(0);
}
Status DBImpl::TEST_SwitchWAL() {
WriteContext write_context;
InstrumentedMutexLock l(&mutex_);
void* writer = TEST_BeginWrite();
auto s = SwitchWAL(&write_context);
TEST_EndWrite(writer);
return s;
}
Status DBImpl::TEST_ResumeImpl(DBRecoverContext context) {
InstrumentedMutexLock l(&mutex_);
return ResumeImpl(context, Env::IOActivity::kFlush);
}
uint64_t DBImpl::TEST_MaxNextLevelOverlappingBytes(
ColumnFamilyHandle* column_family) {
ColumnFamilyData* cfd;
if (column_family == nullptr) {
cfd = default_cf_handle_->cfd();
} else {
auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
cfd = cfh->cfd();
}
InstrumentedMutexLock l(&mutex_);
return cfd->current()->storage_info()->MaxNextLevelOverlappingBytes();
}
void DBImpl::TEST_GetFilesMetaData(
ColumnFamilyHandle* column_family,
std::vector<std::vector<FileMetaData>>* metadata,
std::vector<std::shared_ptr<BlobFileMetaData>>* blob_metadata) {
assert(metadata);
auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
assert(cfh);
auto cfd = cfh->cfd();
assert(cfd);
InstrumentedMutexLock l(&mutex_);
const auto* current = cfd->current();
assert(current);
const auto* vstorage = current->storage_info();
assert(vstorage);
metadata->resize(NumberLevels());
for (int level = 0; level < NumberLevels(); ++level) {
const std::vector<FileMetaData*>& files = vstorage->LevelFiles(level);
(*metadata)[level].clear();
(*metadata)[level].reserve(files.size());
for (const auto& f : files) {
(*metadata)[level].push_back(*f);
}
}
if (blob_metadata) {
*blob_metadata = vstorage->GetBlobFiles();
}
}
uint64_t DBImpl::TEST_Current_Manifest_FileNo() {
InstrumentedMutexLock l(&mutex_);
return versions_->manifest_file_number();
}
uint64_t DBImpl::TEST_Current_Next_FileNo() {
return versions_->current_next_file_number();
}
Status DBImpl::TEST_CompactRange(int level, const Slice* begin,
const Slice* end,
ColumnFamilyHandle* column_family,
bool disallow_trivial_move) {
ColumnFamilyData* cfd;
if (column_family == nullptr) {
cfd = default_cf_handle_->cfd();
} else {
auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
cfd = cfh->cfd();
}
int output_level =
(cfd->ioptions().compaction_style == kCompactionStyleUniversal ||
cfd->ioptions().compaction_style == kCompactionStyleFIFO)
? level
: level + 1;
return RunManualCompaction(
cfd, level, output_level, CompactRangeOptions(), begin, end, true,
disallow_trivial_move,
std::numeric_limits<uint64_t>::max() /*max_file_num_to_ignore*/,
"" /*trim_ts*/);
}
Status DBImpl::TEST_SwitchMemtable(ColumnFamilyData* cfd) {
WriteContext write_context;
InstrumentedMutexLock l(&mutex_);
if (cfd == nullptr) {
cfd = default_cf_handle_->cfd();
}
Status s;
void* writer = TEST_BeginWrite();
if (two_write_queues_) {
WriteThread::Writer nonmem_w;
nonmem_write_thread_.EnterUnbatched(&nonmem_w, &mutex_);
s = SwitchMemtable(cfd, &write_context);
nonmem_write_thread_.ExitUnbatched(&nonmem_w);
} else {
s = SwitchMemtable(cfd, &write_context);
}
TEST_EndWrite(writer);
return s;
}
Status DBImpl::TEST_FlushMemTable(bool wait, bool allow_write_stall,
ColumnFamilyHandle* cfh) {
FlushOptions fo;
fo.wait = wait;
fo.allow_write_stall = allow_write_stall;
ColumnFamilyData* cfd;
if (cfh == nullptr) {
cfd = default_cf_handle_->cfd();
} else {
auto cfhi = static_cast_with_check<ColumnFamilyHandleImpl>(cfh);
cfd = cfhi->cfd();
}
return FlushMemTable(cfd, fo, FlushReason::kTest);
}
Status DBImpl::TEST_FlushMemTable(ColumnFamilyData* cfd,
const FlushOptions& flush_opts) {
return FlushMemTable(cfd, flush_opts, FlushReason::kTest);
}
Status DBImpl::TEST_FlushMemTableWithListenerWait(bool allow_write_stall,
ColumnFamilyHandle* cfh) {
FlushOptions fo;
fo.wait = true;
fo.listener_wait = true;
fo.allow_write_stall = allow_write_stall;
ColumnFamilyData* cfd;
if (cfh == nullptr) {
cfd = default_cf_handle_->cfd();
} else {
auto cfhi = static_cast_with_check<ColumnFamilyHandleImpl>(cfh);
cfd = cfhi->cfd();
}
return FlushMemTable(cfd, fo, FlushReason::kTest);
}
Status DBImpl::TEST_AtomicFlushMemTables(
const autovector<ColumnFamilyData*>& provided_candidate_cfds,
const FlushOptions& flush_opts) {
return AtomicFlushMemTables(flush_opts, FlushReason::kTest,
provided_candidate_cfds);
}
Status DBImpl::TEST_WaitForBackgroundWork() {
InstrumentedMutexLock l(&mutex_);
WaitForBackgroundWork();
return error_handler_.GetBGError();
}
Status DBImpl::TEST_WaitForFlushMemTable(ColumnFamilyHandle* column_family) {
ColumnFamilyData* cfd;
if (column_family == nullptr) {
cfd = default_cf_handle_->cfd();
} else {
auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
cfd = cfh->cfd();
}
return WaitForFlushMemTable(cfd, nullptr, false);
}
Status DBImpl::TEST_WaitForCompact() {
return WaitForCompact(WaitForCompactOptions());
}
Status DBImpl::TEST_WaitForCompact(
const WaitForCompactOptions& wait_for_compact_options) {
return WaitForCompact(wait_for_compact_options);
}
Status DBImpl::TEST_WaitForPurge() {
InstrumentedMutexLock l(&mutex_);
while (bg_purge_scheduled_ && error_handler_.GetBGError().ok()) {
bg_cv_.Wait();
}
return error_handler_.GetBGError();
}
Status DBImpl::TEST_GetBGError() {
InstrumentedMutexLock l(&mutex_);
return error_handler_.GetBGError();
}
bool DBImpl::TEST_IsRecoveryInProgress() {
InstrumentedMutexLock l(&mutex_);
return error_handler_.IsRecoveryInProgress();
}
void DBImpl::TEST_LockMutex() { mutex_.Lock(); }
void DBImpl::TEST_UnlockMutex() { mutex_.Unlock(); }
void DBImpl::TEST_SignalAllBgCv() { bg_cv_.SignalAll(); }
void* DBImpl::TEST_BeginWrite() {
auto w = new WriteThread::Writer();
write_thread_.EnterUnbatched(w, &mutex_);
return static_cast<void*>(w);
}
void DBImpl::TEST_EndWrite(void* w) {
auto writer = static_cast<WriteThread::Writer*>(w);
write_thread_.ExitUnbatched(writer);
delete writer;
}
size_t DBImpl::TEST_LogsToFreeSize() {
InstrumentedMutexLock l(&wal_write_mutex_);
return wals_to_free_.size();
}
uint64_t DBImpl::TEST_LogfileNumber() {
InstrumentedMutexLock l(&mutex_);
return cur_wal_number_;
}
void DBImpl::TEST_GetAllBlockCaches(
std::unordered_set<const Cache*>* cache_set) {
InstrumentedMutexLock l(&mutex_);
for (auto cfd : *versions_->GetColumnFamilySet()) {
if (const auto bbto =
cfd->GetCurrentMutableCFOptions()
.table_factory->GetOptions<BlockBasedTableOptions>()) {
cache_set->insert(bbto->block_cache.get());
}
}
}
uint64_t DBImpl::TEST_FindMinLogContainingOutstandingPrep() {
return logs_with_prep_tracker_.FindMinLogContainingOutstandingPrep();
}
size_t DBImpl::TEST_PreparedSectionCompletedSize() {
return logs_with_prep_tracker_.TEST_PreparedSectionCompletedSize();
}
size_t DBImpl::TEST_LogsWithPrepSize() {
return logs_with_prep_tracker_.TEST_LogsWithPrepSize();
}
uint64_t DBImpl::TEST_FindMinPrepLogReferencedByMemTable() {
autovector<ReadOnlyMemTable*> empty_list;
return FindMinPrepLogReferencedByMemTable(versions_.get(), empty_list);
}
Status DBImpl::TEST_GetLatestMutableCFOptions(
ColumnFamilyHandle* column_family, MutableCFOptions* mutable_cf_options) {
InstrumentedMutexLock l(&mutex_);
auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
*mutable_cf_options = cfh->cfd()->GetLatestMutableCFOptions();
return Status::OK();
}
int DBImpl::TEST_BGCompactionsAllowed() const {
InstrumentedMutexLock l(&mutex_);
return GetBGJobLimits().max_compactions;
}
int DBImpl::TEST_BGFlushesAllowed() const {
InstrumentedMutexLock l(&mutex_);
return GetBGJobLimits().max_flushes;
}
int DBImpl::TEST_NumRunningBottomCompactions() const {
mutex_.AssertHeld();
return num_running_bottom_compactions_;
}
SequenceNumber DBImpl::TEST_GetLastVisibleSequence() const {
if (last_seq_same_as_publish_seq_) {
return versions_->LastSequence();
} else {
return versions_->LastAllocatedSequence();
}
}
size_t DBImpl::TEST_GetWalPreallocateBlockSize(
uint64_t write_buffer_size) const {
InstrumentedMutexLock l(&mutex_);
return GetWalPreallocateBlockSize(write_buffer_size);
}
void DBImpl::TEST_WaitForPeriodicTaskRun(std::function<void()> callback) const {
periodic_task_scheduler_.TEST_WaitForRun(callback);
}
const PeriodicTaskScheduler& DBImpl::TEST_GetPeriodicTaskScheduler() const {
return periodic_task_scheduler_;
}
SeqnoToTimeMapping DBImpl::TEST_GetSeqnoToTimeMapping() const {
InstrumentedMutexLock l(&mutex_);
return seqno_to_time_mapping_;
}
const autovector<uint64_t>& DBImpl::TEST_GetFilesToQuarantine() const {
InstrumentedMutexLock l(&mutex_);
return error_handler_.GetFilesToQuarantine();
}
void DBImpl::TEST_DeleteObsoleteFiles() {
InstrumentedMutexLock l(&mutex_);
DeleteObsoleteFiles();
}
size_t DBImpl::TEST_EstimateInMemoryStatsHistorySize() const {
InstrumentedMutexLock l(&const_cast<DBImpl*>(this)->stats_history_mutex_);
return EstimateInMemoryStatsHistorySize();
}
void DBImpl::TEST_VerifyNoObsoleteFilesCached(
bool db_mutex_already_held) const {
// This check is somewhat expensive and obscure to make a part of every
// unit test in every build variety. Thus, we only enable it for ASAN builds.
if (!kMustFreeHeapAllocations) {
return;
}
std::optional<InstrumentedMutexLock> l;
if (db_mutex_already_held) {
mutex_.AssertHeld();
} else {
l.emplace(&mutex_);
}
if (!opened_successfully_) {
// We don't need to pro-actively clean up open files during DB::Open()
// if we know we are about to fail and clean up in Close().
return;
}
if (disable_delete_obsolete_files_ > 0) {
// For better or worse, DB::Close() is allowed with deletions disabled.
// Since we generally associate clean-up of open files with deleting them,
// we allow "obsolete" open files when deletions are disabled.
return;
}
// Live and "quarantined" files are allowed to be open in table cache
UnorderedSet<uint64_t> live_and_quar_files;
for (auto cfd : *versions_->GetColumnFamilySet()) {
if (cfd->IsDropped()) {
continue;
}
if (auto* mgr = cfd->blob_partition_manager(); mgr != nullptr) {
mgr->GetActiveBlobFileNumbers(&live_and_quar_files);
mgr->GetProtectedBlobFileNumbers(&live_and_quar_files);
}
// Iterate over live versions
Version* current = cfd->current();
Version* ver = current;
do {
// Sneakily add both SST and blob files to the same list
std::vector<uint64_t> live_files_vec;
ver->AddLiveFiles(&live_files_vec, &live_files_vec);
live_and_quar_files.insert(live_files_vec.begin(), live_files_vec.end());
ver = ver->Next();
} while (ver != current);
}
{
const auto& quar_files = error_handler_.GetFilesToQuarantine();
live_and_quar_files.insert(quar_files.begin(), quar_files.end());
}
auto fn = [&live_and_quar_files](const Slice& key, Cache::ObjectPtr, size_t,
const Cache::CacheItemHelper*) {
// See TableCache and BlobFileCache
assert(key.size() == sizeof(uint64_t));
uint64_t file_number;
GetUnaligned(reinterpret_cast<const uint64_t*>(key.data()), &file_number);
// Assert file is in live/quarantined set
bool cached_file_is_live_or_quar =
live_and_quar_files.find(file_number) != live_and_quar_files.end();
if (!cached_file_is_live_or_quar) {
// Fail with useful info
std::cerr << "File " << file_number << " is not live nor quarantined"
<< std::endl;
assert(cached_file_is_live_or_quar);
}
};
table_cache_->ApplyToAllEntries(fn, {});
}
} // namespace ROCKSDB_NAMESPACE
#endif // NDEBUG