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e265e08a02
rocksdb/db/db_impl_compaction_flush.cc
Yanqin Jin e265e08a02 Avoid switching empty memtable in certain cases (#4792) 
Summary:
in certain cases, we do not perform memtable switching if the active
memtable of the column family is empty. Two exceptions:
1. In manual flush, if cached_recoverable_state_empty_ is false, then we need
   to switch memtable due to requirement of transaction.
2. In switch WAL, we need to switch memtable anyway because we have to seal the
   memtable if the WAL on which it depends will be closed.

This change can potentially delay the occurence of write stalls because number
of memtables increase more slowly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4792

Differential Revision: D13499501

Pulled By: riversand963

fbshipit-source-id: 91c9b17ae753578578039f3851667d93610005e1
2019-01-07 10:06:49 -08:00

2795 lines
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// 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.
#include "db/db_impl.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include "db/builder.h"
#include "db/error_handler.h"
#include "db/event_helpers.h"
#include "monitoring/iostats_context_imp.h"
#include "monitoring/perf_context_imp.h"
#include "monitoring/thread_status_updater.h"
#include "monitoring/thread_status_util.h"
#include "util/sst_file_manager_impl.h"
#include "util/sync_point.h"
namespace rocksdb {
bool DBImpl::EnoughRoomForCompaction(
ColumnFamilyData* cfd, const std::vector<CompactionInputFiles>& inputs,
bool* sfm_reserved_compact_space, LogBuffer* log_buffer) {
// Check if we have enough room to do the compaction
bool enough_room = true;
#ifndef ROCKSDB_LITE
auto sfm = static_cast<SstFileManagerImpl*>(
immutable_db_options_.sst_file_manager.get());
if (sfm) {
// Pass the current bg_error_ to SFM so it can decide what checks to
// perform. If this DB instance hasn't seen any error yet, the SFM can be
// optimistic and not do disk space checks
enough_room =
sfm->EnoughRoomForCompaction(cfd, inputs, error_handler_.GetBGError());
if (enough_room) {
*sfm_reserved_compact_space = true;
}
}
#else
(void)cfd;
(void)inputs;
(void)sfm_reserved_compact_space;
#endif // ROCKSDB_LITE
if (!enough_room) {
// Just in case tests want to change the value of enough_room
TEST_SYNC_POINT_CALLBACK(
"DBImpl::BackgroundCompaction():CancelledCompaction", &enough_room);
ROCKS_LOG_BUFFER(log_buffer,
"Cancelled compaction because not enough room");
RecordTick(stats_, COMPACTION_CANCELLED, 1);
}
return enough_room;
}
Status DBImpl::SyncClosedLogs(JobContext* job_context) {
TEST_SYNC_POINT("DBImpl::SyncClosedLogs:Start");
mutex_.AssertHeld();
autovector<log::Writer*, 1> logs_to_sync;
uint64_t current_log_number = logfile_number_;
while (logs_.front().number < current_log_number &&
logs_.front().getting_synced) {
log_sync_cv_.Wait();
}
for (auto it = logs_.begin();
it != logs_.end() && it->number < current_log_number; ++it) {
auto& log = *it;
assert(!log.getting_synced);
log.getting_synced = true;
logs_to_sync.push_back(log.writer);
}
Status s;
if (!logs_to_sync.empty()) {
mutex_.Unlock();
for (log::Writer* log : logs_to_sync) {
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"[JOB %d] Syncing log #%" PRIu64, job_context->job_id,
log->get_log_number());
s = log->file()->Sync(immutable_db_options_.use_fsync);
if (!s.ok()) {
break;
}
}
if (s.ok()) {
s = directories_.GetWalDir()->Fsync();
}
mutex_.Lock();
// "number <= current_log_number - 1" is equivalent to
// "number < current_log_number".
MarkLogsSynced(current_log_number - 1, true, s);
if (!s.ok()) {
error_handler_.SetBGError(s, BackgroundErrorReason::kFlush);
TEST_SYNC_POINT("DBImpl::SyncClosedLogs:Failed");
return s;
}
}
return s;
}
Status DBImpl::FlushMemTableToOutputFile(
ColumnFamilyData* cfd, const MutableCFOptions& mutable_cf_options,
bool* made_progress, JobContext* job_context,
SuperVersionContext* superversion_context, LogBuffer* log_buffer) {
mutex_.AssertHeld();
assert(cfd->imm()->NumNotFlushed() != 0);
assert(cfd->imm()->IsFlushPending());
SequenceNumber earliest_write_conflict_snapshot;
std::vector<SequenceNumber> snapshot_seqs =
snapshots_.GetAll(&earliest_write_conflict_snapshot);
auto snapshot_checker = snapshot_checker_.get();
if (use_custom_gc_ && snapshot_checker == nullptr) {
snapshot_checker = DisableGCSnapshotChecker::Instance();
}
FlushJob flush_job(
dbname_, cfd, immutable_db_options_, mutable_cf_options,
nullptr /* memtable_id */, env_options_for_compaction_, versions_.get(),
&mutex_, &shutting_down_, snapshot_seqs, earliest_write_conflict_snapshot,
snapshot_checker, job_context, log_buffer, directories_.GetDbDir(),
GetDataDir(cfd, 0U),
GetCompressionFlush(*cfd->ioptions(), mutable_cf_options), stats_,
&event_logger_, mutable_cf_options.report_bg_io_stats,
true /* sync_output_directory */, true /* write_manifest */);
FileMetaData file_meta;
TEST_SYNC_POINT("DBImpl::FlushMemTableToOutputFile:BeforePickMemtables");
flush_job.PickMemTable();
TEST_SYNC_POINT("DBImpl::FlushMemTableToOutputFile:AfterPickMemtables");
#ifndef ROCKSDB_LITE
// may temporarily unlock and lock the mutex.
NotifyOnFlushBegin(cfd, &file_meta, mutable_cf_options, job_context->job_id,
flush_job.GetTableProperties());
#endif // ROCKSDB_LITE
Status s;
if (logfile_number_ > 0 &&
versions_->GetColumnFamilySet()->NumberOfColumnFamilies() > 1) {
// If there are more than one column families, we need to make sure that
// all the log files except the most recent one are synced. Otherwise if
// the host crashes after flushing and before WAL is persistent, the
// flushed SST may contain data from write batches whose updates to
// other column families are missing.
// SyncClosedLogs() may unlock and re-lock the db_mutex.
s = SyncClosedLogs(job_context);
} else {
TEST_SYNC_POINT("DBImpl::SyncClosedLogs:Skip");
}
// Within flush_job.Run, rocksdb may call event listener to notify
// file creation and deletion.
//
// Note that flush_job.Run will unlock and lock the db_mutex,
// and EventListener callback will be called when the db_mutex
// is unlocked by the current thread.
if (s.ok()) {
s = flush_job.Run(&logs_with_prep_tracker_, &file_meta);
} else {
flush_job.Cancel();
}
if (s.ok()) {
InstallSuperVersionAndScheduleWork(cfd, superversion_context,
mutable_cf_options);
if (made_progress) {
*made_progress = true;
}
VersionStorageInfo::LevelSummaryStorage tmp;
ROCKS_LOG_BUFFER(log_buffer, "[%s] Level summary: %s\n",
cfd->GetName().c_str(),
cfd->current()->storage_info()->LevelSummary(&tmp));
}
if (!s.ok() && !s.IsShutdownInProgress()) {
Status new_bg_error = s;
error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush);
}
if (s.ok()) {
#ifndef ROCKSDB_LITE
// may temporarily unlock and lock the mutex.
NotifyOnFlushCompleted(cfd, &file_meta, mutable_cf_options,
job_context->job_id, flush_job.GetTableProperties());
auto sfm = static_cast<SstFileManagerImpl*>(
immutable_db_options_.sst_file_manager.get());
if (sfm) {
// Notify sst_file_manager that a new file was added
std::string file_path = MakeTableFileName(
cfd->ioptions()->cf_paths[0].path, file_meta.fd.GetNumber());
sfm->OnAddFile(file_path);
if (sfm->IsMaxAllowedSpaceReached()) {
Status new_bg_error = Status::SpaceLimit("Max allowed space was reached");
TEST_SYNC_POINT_CALLBACK(
"DBImpl::FlushMemTableToOutputFile:MaxAllowedSpaceReached",
&new_bg_error);
error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush);
}
}
#endif // ROCKSDB_LITE
}
return s;
}
Status DBImpl::FlushMemTablesToOutputFiles(
const autovector<BGFlushArg>& bg_flush_args, bool* made_progress,
JobContext* job_context, LogBuffer* log_buffer) {
if (immutable_db_options_.atomic_flush) {
return AtomicFlushMemTablesToOutputFiles(bg_flush_args, made_progress,
job_context, log_buffer);
}
Status status;
for (auto& arg : bg_flush_args) {
ColumnFamilyData* cfd = arg.cfd_;
const MutableCFOptions& mutable_cf_options =
*cfd->GetLatestMutableCFOptions();
SuperVersionContext* superversion_context = arg.superversion_context_;
Status s = FlushMemTableToOutputFile(cfd, mutable_cf_options, made_progress,
job_context, superversion_context,
log_buffer);
if (!s.ok()) {
status = s;
if (!s.IsShutdownInProgress()) {
// At this point, DB is not shutting down, nor is cfd dropped.
// Something is wrong, thus we break out of the loop.
break;
}
}
}
return status;
}
/*
* Atomically flushes multiple column families.
*
* For each column family, all memtables with ID smaller than or equal to the
* ID specified in bg_flush_args will be flushed. Only after all column
* families finish flush will this function commit to MANIFEST. If any of the
* column families are not flushed successfully, this function does not have
* any side-effect on the state of the database.
*/
Status DBImpl::AtomicFlushMemTablesToOutputFiles(
const autovector<BGFlushArg>& bg_flush_args, bool* made_progress,
JobContext* job_context, LogBuffer* log_buffer) {
mutex_.AssertHeld();
autovector<ColumnFamilyData*> cfds;
for (const auto& arg : bg_flush_args) {
cfds.emplace_back(arg.cfd_);
}
#ifndef NDEBUG
for (const auto cfd : cfds) {
assert(cfd->imm()->NumNotFlushed() != 0);
assert(cfd->imm()->IsFlushPending());
}
#endif /* !NDEBUG */
SequenceNumber earliest_write_conflict_snapshot;
std::vector<SequenceNumber> snapshot_seqs =
snapshots_.GetAll(&earliest_write_conflict_snapshot);
auto snapshot_checker = snapshot_checker_.get();
if (use_custom_gc_ && snapshot_checker == nullptr) {
snapshot_checker = DisableGCSnapshotChecker::Instance();
}
autovector<Directory*> distinct_output_dirs;
std::vector<FlushJob> jobs;
int num_cfs = static_cast<int>(cfds.size());
for (int i = 0; i < num_cfs; ++i) {
auto cfd = cfds[i];
Directory* data_dir = GetDataDir(cfd, 0U);
// Add to distinct output directories if eligible. Use linear search. Since
// the number of elements in the vector is not large, performance should be
// tolerable.
bool found = false;
for (const auto dir : distinct_output_dirs) {
if (dir == data_dir) {
found = true;
break;
}
}
if (!found) {
distinct_output_dirs.emplace_back(data_dir);
}
const MutableCFOptions& mutable_cf_options =
*cfd->GetLatestMutableCFOptions();
const uint64_t* max_memtable_id = &(bg_flush_args[i].max_memtable_id_);
jobs.emplace_back(
dbname_, cfds[i], immutable_db_options_, mutable_cf_options,
max_memtable_id, env_options_for_compaction_, versions_.get(), &mutex_,
&shutting_down_, snapshot_seqs, earliest_write_conflict_snapshot,
snapshot_checker, job_context, log_buffer, directories_.GetDbDir(),
data_dir, GetCompressionFlush(*cfd->ioptions(), mutable_cf_options),
stats_, &event_logger_, mutable_cf_options.report_bg_io_stats,
false /* sync_output_directory */, false /* write_manifest */);
jobs.back().PickMemTable();
}
autovector<FileMetaData> file_meta;
Status s;
assert(num_cfs == static_cast<int>(jobs.size()));
for (int i = 0; i != num_cfs; ++i) {
file_meta.emplace_back();
#ifndef ROCKSDB_LITE
const MutableCFOptions& mutable_cf_options =
*cfds[i]->GetLatestMutableCFOptions();
// may temporarily unlock and lock the mutex.
NotifyOnFlushBegin(cfds[i], &file_meta[i], mutable_cf_options,
job_context->job_id, jobs[i].GetTableProperties());
#endif /* !ROCKSDB_LITE */
}
if (logfile_number_ > 0) {
// TODO (yanqin) investigate whether we should sync the closed logs for
// single column family case.
s = SyncClosedLogs(job_context);
}
// exec_status stores the execution status of flush_jobs as
// <bool /* executed */, Status /* status code */>
autovector<std::pair<bool, Status>> exec_status;
for (int i = 0; i != num_cfs; ++i) {
// Initially all jobs are not executed, with status OK.
exec_status.emplace_back(false, Status::OK());
}
if (s.ok()) {
// TODO (yanqin): parallelize jobs with threads.
for (int i = 1; i != num_cfs; ++i) {
exec_status[i].second =
jobs[i].Run(&logs_with_prep_tracker_, &file_meta[i]);
exec_status[i].first = true;
}
if (num_cfs > 1) {
TEST_SYNC_POINT(
"DBImpl::AtomicFlushMemTablesToOutputFiles:SomeFlushJobsComplete:1");
TEST_SYNC_POINT(
"DBImpl::AtomicFlushMemTablesToOutputFiles:SomeFlushJobsComplete:2");
}
exec_status[0].second =
jobs[0].Run(&logs_with_prep_tracker_, &file_meta[0]);
exec_status[0].first = true;
Status error_status;
for (const auto& e : exec_status) {
if (!e.second.ok()) {
s = e.second;
if (!e.second.IsShutdownInProgress()) {
// If a flush job did not return OK, and the CF is not dropped, and
// the DB is not shutting down, then we have to return this result to
// caller later.
error_status = e.second;
}
}
}
s = error_status.ok() ? s : error_status;
}
if (s.ok() || s.IsShutdownInProgress()) {
// Sync on all distinct output directories.
for (auto dir : distinct_output_dirs) {
if (dir != nullptr) {
s = dir->Fsync();
if (!s.ok()) {
break;
}
}
}
if (s.ok()) {
autovector<const autovector<MemTable*>*> mems_list;
for (int i = 0; i != num_cfs; ++i) {
if (cfds[i]->IsDropped()) {
continue;
}
const auto& mems = jobs[i].GetMemTables();
mems_list.emplace_back(&mems);
}
autovector<ColumnFamilyData*> all_cfds;
autovector<MemTableList*> imm_lists;
autovector<const MutableCFOptions*> mutable_cf_options_list;
for (auto cfd : *versions_->GetColumnFamilySet()) {
if (cfd->IsDropped()) {
continue;
}
all_cfds.emplace_back(cfd);
imm_lists.emplace_back(cfd->imm());
mutable_cf_options_list.emplace_back(cfd->GetLatestMutableCFOptions());
}
s = MemTableList::TryInstallMemtableFlushResults(
imm_lists, all_cfds, mutable_cf_options_list, mems_list,
&atomic_flush_commit_in_progress_, &logs_with_prep_tracker_,
versions_.get(), &mutex_, file_meta, &job_context->memtables_to_free,
directories_.GetDbDir(), log_buffer);
}
}
if (s.ok() || s.IsShutdownInProgress()) {
assert(num_cfs ==
static_cast<int>(job_context->superversion_contexts.size()));
for (int i = 0; i != num_cfs; ++i) {
if (cfds[i]->IsDropped()) {
continue;
}
InstallSuperVersionAndScheduleWork(cfds[i],
&job_context->superversion_contexts[i],
*cfds[i]->GetLatestMutableCFOptions());
VersionStorageInfo::LevelSummaryStorage tmp;
ROCKS_LOG_BUFFER(log_buffer, "[%s] Level summary: %s\n",
cfds[i]->GetName().c_str(),
cfds[i]->current()->storage_info()->LevelSummary(&tmp));
}
if (made_progress) {
*made_progress = true;
}
#ifndef ROCKSDB_LITE
auto sfm = static_cast<SstFileManagerImpl*>(
immutable_db_options_.sst_file_manager.get());
for (int i = 0; i != num_cfs; ++i) {
if (cfds[i]->IsDropped()) {
continue;
}
NotifyOnFlushCompleted(cfds[i], &file_meta[i],
*cfds[i]->GetLatestMutableCFOptions(),
job_context->job_id, jobs[i].GetTableProperties());
if (sfm) {
std::string file_path = MakeTableFileName(
cfds[i]->ioptions()->cf_paths[0].path, file_meta[i].fd.GetNumber());
sfm->OnAddFile(file_path);
if (sfm->IsMaxAllowedSpaceReached() &&
error_handler_.GetBGError().ok()) {
Status new_bg_error =
Status::SpaceLimit("Max allowed space was reached");
error_handler_.SetBGError(new_bg_error,
BackgroundErrorReason::kFlush);
}
}
}
#endif // ROCKSDB_LITE
}
// Need to undo atomic flush if something went wrong, i.e. s is not OK and
// it is not because of CF drop.
if (!s.ok() && !s.IsShutdownInProgress()) {
// Have to cancel the flush jobs that have NOT executed because we need to
// unref the versions.
for (int i = 0; i != num_cfs; ++i) {
if (!exec_status[i].first) {
jobs[i].Cancel();
}
}
for (int i = 0; i != num_cfs; ++i) {
if (exec_status[i].first && exec_status[i].second.ok()) {
auto& mems = jobs[i].GetMemTables();
cfds[i]->imm()->RollbackMemtableFlush(mems,
file_meta[i].fd.GetNumber());
}
}
Status new_bg_error = s;
error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush);
}
return s;
}
void DBImpl::NotifyOnFlushBegin(ColumnFamilyData* cfd, FileMetaData* file_meta,
const MutableCFOptions& mutable_cf_options,
int job_id, TableProperties prop) {
#ifndef ROCKSDB_LITE
if (immutable_db_options_.listeners.size() == 0U) {
return;
}
mutex_.AssertHeld();
if (shutting_down_.load(std::memory_order_acquire)) {
return;
}
bool triggered_writes_slowdown =
(cfd->current()->storage_info()->NumLevelFiles(0) >=
mutable_cf_options.level0_slowdown_writes_trigger);
bool triggered_writes_stop =
(cfd->current()->storage_info()->NumLevelFiles(0) >=
mutable_cf_options.level0_stop_writes_trigger);
// release lock while notifying events
mutex_.Unlock();
{
FlushJobInfo info;
info.cf_name = cfd->GetName();
// TODO(yhchiang): make db_paths dynamic in case flush does not
// go to L0 in the future.
info.file_path = MakeTableFileName(cfd->ioptions()->cf_paths[0].path,
file_meta->fd.GetNumber());
info.thread_id = env_->GetThreadID();
info.job_id = job_id;
info.triggered_writes_slowdown = triggered_writes_slowdown;
info.triggered_writes_stop = triggered_writes_stop;
info.smallest_seqno = file_meta->fd.smallest_seqno;
info.largest_seqno = file_meta->fd.largest_seqno;
info.table_properties = prop;
info.flush_reason = cfd->GetFlushReason();
for (auto listener : immutable_db_options_.listeners) {
listener->OnFlushBegin(this, info);
}
}
mutex_.Lock();
// no need to signal bg_cv_ as it will be signaled at the end of the
// flush process.
#else
(void)cfd;
(void)file_meta;
(void)mutable_cf_options;
(void)job_id;
(void)prop;
#endif // ROCKSDB_LITE
}
void DBImpl::NotifyOnFlushCompleted(ColumnFamilyData* cfd,
FileMetaData* file_meta,
const MutableCFOptions& mutable_cf_options,
int job_id, TableProperties prop) {
#ifndef ROCKSDB_LITE
if (immutable_db_options_.listeners.size() == 0U) {
return;
}
mutex_.AssertHeld();
if (shutting_down_.load(std::memory_order_acquire)) {
return;
}
bool triggered_writes_slowdown =
(cfd->current()->storage_info()->NumLevelFiles(0) >=
mutable_cf_options.level0_slowdown_writes_trigger);
bool triggered_writes_stop =
(cfd->current()->storage_info()->NumLevelFiles(0) >=
mutable_cf_options.level0_stop_writes_trigger);
// release lock while notifying events
mutex_.Unlock();
{
FlushJobInfo info;
info.cf_name = cfd->GetName();
// TODO(yhchiang): make db_paths dynamic in case flush does not
// go to L0 in the future.
info.file_path = MakeTableFileName(cfd->ioptions()->cf_paths[0].path,
file_meta->fd.GetNumber());
info.thread_id = env_->GetThreadID();
info.job_id = job_id;
info.triggered_writes_slowdown = triggered_writes_slowdown;
info.triggered_writes_stop = triggered_writes_stop;
info.smallest_seqno = file_meta->fd.smallest_seqno;
info.largest_seqno = file_meta->fd.largest_seqno;
info.table_properties = prop;
info.flush_reason = cfd->GetFlushReason();
for (auto listener : immutable_db_options_.listeners) {
listener->OnFlushCompleted(this, info);
}
}
mutex_.Lock();
// no need to signal bg_cv_ as it will be signaled at the end of the
// flush process.
#else
(void)cfd;
(void)file_meta;
(void)mutable_cf_options;
(void)job_id;
(void)prop;
#endif // ROCKSDB_LITE
}
Status DBImpl::CompactRange(const CompactRangeOptions& options,
ColumnFamilyHandle* column_family,
const Slice* begin, const Slice* end) {
auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
auto cfd = cfh->cfd();
if (options.target_path_id >= cfd->ioptions()->cf_paths.size()) {
return Status::InvalidArgument("Invalid target path ID");
}
bool exclusive = options.exclusive_manual_compaction;
bool flush_needed = true;
if (begin != nullptr && end != nullptr) {
// TODO(ajkr): We could also optimize away the flush in certain cases where
// one/both sides of the interval are unbounded. But it requires more
// changes to RangesOverlapWithMemtables.
Range range(*begin, *end);
SuperVersion* super_version = cfd->GetReferencedSuperVersion(&mutex_);
cfd->RangesOverlapWithMemtables({range}, super_version, &flush_needed);
CleanupSuperVersion(super_version);
}
Status s;
if (flush_needed) {
FlushOptions fo;
fo.allow_write_stall = options.allow_write_stall;
if (immutable_db_options_.atomic_flush) {
autovector<ColumnFamilyData*> cfds;
mutex_.Lock();
SelectColumnFamiliesForAtomicFlush(&cfds);
mutex_.Unlock();
s = AtomicFlushMemTables(cfds, fo, FlushReason::kManualCompaction,
false /* writes_stopped */);
} else {
s = FlushMemTable(cfd, fo, FlushReason::kManualCompaction,
false /* writes_stopped*/);
}
if (!s.ok()) {
LogFlush(immutable_db_options_.info_log);
return s;
}
}
int max_level_with_files = 0;
{
InstrumentedMutexLock l(&mutex_);
Version* base = cfd->current();
for (int level = 1; level < base->storage_info()->num_non_empty_levels();
level++) {
if (base->storage_info()->OverlapInLevel(level, begin, end)) {
max_level_with_files = level;
}
}
}
int final_output_level = 0;
if (cfd->ioptions()->compaction_style == kCompactionStyleUniversal &&
cfd->NumberLevels() > 1) {
// Always compact all files together.
final_output_level = cfd->NumberLevels() - 1;
// if bottom most level is reserved
if (immutable_db_options_.allow_ingest_behind) {
final_output_level--;
}
s = RunManualCompaction(cfd, ColumnFamilyData::kCompactAllLevels,
final_output_level, options.target_path_id,
options.max_subcompactions, begin, end, exclusive);
} else {
for (int level = 0; level <= max_level_with_files; level++) {
int output_level;
// in case the compaction is universal or if we're compacting the
// bottom-most level, the output level will be the same as input one.
// level 0 can never be the bottommost level (i.e. if all files are in
// level 0, we will compact to level 1)
if (cfd->ioptions()->compaction_style == kCompactionStyleUniversal ||
cfd->ioptions()->compaction_style == kCompactionStyleFIFO) {
output_level = level;
} else if (level == max_level_with_files && level > 0) {
if (options.bottommost_level_compaction ==
BottommostLevelCompaction::kSkip) {
// Skip bottommost level compaction
continue;
} else if (options.bottommost_level_compaction ==
BottommostLevelCompaction::kIfHaveCompactionFilter &&
cfd->ioptions()->compaction_filter == nullptr &&
cfd->ioptions()->compaction_filter_factory == nullptr) {
// Skip bottommost level compaction since we don't have a compaction
// filter
continue;
}
output_level = level;
} else {
output_level = level + 1;
if (cfd->ioptions()->compaction_style == kCompactionStyleLevel &&
cfd->ioptions()->level_compaction_dynamic_level_bytes &&
level == 0) {
output_level = ColumnFamilyData::kCompactToBaseLevel;
}
}
s = RunManualCompaction(cfd, level, output_level, options.target_path_id,
options.max_subcompactions, begin, end, exclusive);
if (!s.ok()) {
break;
}
if (output_level == ColumnFamilyData::kCompactToBaseLevel) {
final_output_level = cfd->NumberLevels() - 1;
} else if (output_level > final_output_level) {
final_output_level = output_level;
}
TEST_SYNC_POINT("DBImpl::RunManualCompaction()::1");
TEST_SYNC_POINT("DBImpl::RunManualCompaction()::2");
}
}
if (!s.ok()) {
LogFlush(immutable_db_options_.info_log);
return s;
}
if (options.change_level) {
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"[RefitLevel] waiting for background threads to stop");
s = PauseBackgroundWork();
if (s.ok()) {
s = ReFitLevel(cfd, final_output_level, options.target_level);
}
ContinueBackgroundWork();
}
LogFlush(immutable_db_options_.info_log);
{
InstrumentedMutexLock l(&mutex_);
// an automatic compaction that has been scheduled might have been
// preempted by the manual compactions. Need to schedule it back.
MaybeScheduleFlushOrCompaction();
}
return s;
}
Status DBImpl::CompactFiles(const CompactionOptions& compact_options,
ColumnFamilyHandle* column_family,
const std::vector<std::string>& input_file_names,
const int output_level, const int output_path_id,
std::vector<std::string>* const output_file_names) {
#ifdef ROCKSDB_LITE
(void)compact_options;
(void)column_family;
(void)input_file_names;
(void)output_level;
(void)output_path_id;
(void)output_file_names;
// not supported in lite version
return Status::NotSupported("Not supported in ROCKSDB LITE");
#else
if (column_family == nullptr) {
return Status::InvalidArgument("ColumnFamilyHandle must be non-null.");
}
auto cfd = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family)->cfd();
assert(cfd);
Status s;
JobContext job_context(0, true);
LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL,
immutable_db_options_.info_log.get());
// Perform CompactFiles
TEST_SYNC_POINT("TestCompactFiles::IngestExternalFile2");
{
InstrumentedMutexLock l(&mutex_);
// This call will unlock/lock the mutex to wait for current running
// IngestExternalFile() calls to finish.
WaitForIngestFile();
// We need to get current after `WaitForIngestFile`, because
// `IngestExternalFile` may add files that overlap with `input_file_names`
auto* current = cfd->current();
current->Ref();
s = CompactFilesImpl(compact_options, cfd, current, input_file_names,
output_file_names, output_level, output_path_id,
&job_context, &log_buffer);
current->Unref();
}
// Find and delete obsolete files
{
InstrumentedMutexLock l(&mutex_);
// If !s.ok(), this means that Compaction failed. In that case, we want
// to delete all obsolete files we might have created and we force
// FindObsoleteFiles(). This is because job_context does not
// catch all created files if compaction failed.
FindObsoleteFiles(&job_context, !s.ok());
} // release the mutex
// delete unnecessary files if any, this is done outside the mutex
if (job_context.HaveSomethingToClean() ||
job_context.HaveSomethingToDelete() || !log_buffer.IsEmpty()) {
// Have to flush the info logs before bg_compaction_scheduled_--
// because if bg_flush_scheduled_ becomes 0 and the lock is
// released, the deconstructor of DB can kick in and destroy all the
// states of DB so info_log might not be available after that point.
// It also applies to access other states that DB owns.
log_buffer.FlushBufferToLog();
if (job_context.HaveSomethingToDelete()) {
// no mutex is locked here. No need to Unlock() and Lock() here.
PurgeObsoleteFiles(job_context);
}
job_context.Clean();
}
return s;
#endif // ROCKSDB_LITE
}
#ifndef ROCKSDB_LITE
Status DBImpl::CompactFilesImpl(
const CompactionOptions& compact_options, ColumnFamilyData* cfd,
Version* version, const std::vector<std::string>& input_file_names,
std::vector<std::string>* const output_file_names, const int output_level,
int output_path_id, JobContext* job_context, LogBuffer* log_buffer) {
mutex_.AssertHeld();
if (shutting_down_.load(std::memory_order_acquire)) {
return Status::ShutdownInProgress();
}
std::unordered_set<uint64_t> input_set;
for (const auto& file_name : input_file_names) {
input_set.insert(TableFileNameToNumber(file_name));
}
ColumnFamilyMetaData cf_meta;
// TODO(yhchiang): can directly use version here if none of the
// following functions call is pluggable to external developers.
version->GetColumnFamilyMetaData(&cf_meta);
if (output_path_id < 0) {
if (cfd->ioptions()->cf_paths.size() == 1U) {
output_path_id = 0;
} else {
return Status::NotSupported(
"Automatic output path selection is not "
"yet supported in CompactFiles()");
}
}
Status s = cfd->compaction_picker()->SanitizeCompactionInputFiles(
&input_set, cf_meta, output_level);
if (!s.ok()) {
return s;
}
std::vector<CompactionInputFiles> input_files;
s = cfd->compaction_picker()->GetCompactionInputsFromFileNumbers(
&input_files, &input_set, version->storage_info(), compact_options);
if (!s.ok()) {
return s;
}
for (const auto& inputs : input_files) {
if (cfd->compaction_picker()->AreFilesInCompaction(inputs.files)) {
return Status::Aborted(
"Some of the necessary compaction input "
"files are already being compacted");
}
}
bool sfm_reserved_compact_space = false;
// First check if we have enough room to do the compaction
bool enough_room = EnoughRoomForCompaction(
cfd, input_files, &sfm_reserved_compact_space, log_buffer);
if (!enough_room) {
// m's vars will get set properly at the end of this function,
// as long as status == CompactionTooLarge
return Status::CompactionTooLarge();
}
// At this point, CompactFiles will be run.
bg_compaction_scheduled_++;
std::unique_ptr<Compaction> c;
assert(cfd->compaction_picker());
c.reset(cfd->compaction_picker()->CompactFiles(
compact_options, input_files, output_level, version->storage_info(),
*cfd->GetLatestMutableCFOptions(), output_path_id));
// we already sanitized the set of input files and checked for conflicts
// without releasing the lock, so we're guaranteed a compaction can be formed.
assert(c != nullptr);
c->SetInputVersion(version);
// deletion compaction currently not allowed in CompactFiles.
assert(!c->deletion_compaction());
SequenceNumber earliest_write_conflict_snapshot;
std::vector<SequenceNumber> snapshot_seqs =
snapshots_.GetAll(&earliest_write_conflict_snapshot);
auto pending_outputs_inserted_elem =
CaptureCurrentFileNumberInPendingOutputs();
auto snapshot_checker = snapshot_checker_.get();
if (use_custom_gc_ && snapshot_checker == nullptr) {
snapshot_checker = DisableGCSnapshotChecker::Instance();
}
assert(is_snapshot_supported_ || snapshots_.empty());
CompactionJob compaction_job(
job_context->job_id, c.get(), immutable_db_options_,
env_options_for_compaction_, versions_.get(), &shutting_down_,
preserve_deletes_seqnum_.load(), log_buffer, directories_.GetDbDir(),
GetDataDir(c->column_family_data(), c->output_path_id()), stats_, &mutex_,
&error_handler_, snapshot_seqs, earliest_write_conflict_snapshot,
snapshot_checker, table_cache_, &event_logger_,
c->mutable_cf_options()->paranoid_file_checks,
c->mutable_cf_options()->report_bg_io_stats, dbname_,
nullptr); // Here we pass a nullptr for CompactionJobStats because
// CompactFiles does not trigger OnCompactionCompleted(),
// which is the only place where CompactionJobStats is
// returned. The idea of not triggering OnCompationCompleted()
// is that CompactFiles runs in the caller thread, so the user
// should always know when it completes. As a result, it makes
// less sense to notify the users something they should already
// know.
//
// In the future, if we would like to add CompactionJobStats
// support for CompactFiles, we should have CompactFiles API
// pass a pointer of CompactionJobStats as the out-value
// instead of using EventListener.
// Creating a compaction influences the compaction score because the score
// takes running compactions into account (by skipping files that are already
// being compacted). Since we just changed compaction score, we recalculate it
// here.
version->storage_info()->ComputeCompactionScore(*cfd->ioptions(),
*c->mutable_cf_options());
compaction_job.Prepare();
mutex_.Unlock();
TEST_SYNC_POINT("CompactFilesImpl:0");
TEST_SYNC_POINT("CompactFilesImpl:1");
compaction_job.Run();
TEST_SYNC_POINT("CompactFilesImpl:2");
TEST_SYNC_POINT("CompactFilesImpl:3");
mutex_.Lock();
Status status = compaction_job.Install(*c->mutable_cf_options());
if (status.ok()) {
InstallSuperVersionAndScheduleWork(
c->column_family_data(), &job_context->superversion_contexts[0],
*c->mutable_cf_options(), FlushReason::kManualCompaction);
}
c->ReleaseCompactionFiles(s);
#ifndef ROCKSDB_LITE
// Need to make sure SstFileManager does its bookkeeping
auto sfm = static_cast<SstFileManagerImpl*>(
immutable_db_options_.sst_file_manager.get());
if (sfm && sfm_reserved_compact_space) {
sfm->OnCompactionCompletion(c.get());
}
#endif // ROCKSDB_LITE
ReleaseFileNumberFromPendingOutputs(pending_outputs_inserted_elem);
if (status.ok()) {
// Done
} else if (status.IsShutdownInProgress()) {
// Ignore compaction errors found during shutting down
} else {
ROCKS_LOG_WARN(immutable_db_options_.info_log,
"[%s] [JOB %d] Compaction error: %s",
c->column_family_data()->GetName().c_str(),
job_context->job_id, status.ToString().c_str());
error_handler_.SetBGError(status, BackgroundErrorReason::kCompaction);
}
if (output_file_names != nullptr) {
for (const auto newf : c->edit()->GetNewFiles()) {
(*output_file_names)
.push_back(TableFileName(c->immutable_cf_options()->cf_paths,
newf.second.fd.GetNumber(),
newf.second.fd.GetPathId()));
}
}
c.reset();
bg_compaction_scheduled_--;
if (bg_compaction_scheduled_ == 0) {
bg_cv_.SignalAll();
}
TEST_SYNC_POINT("CompactFilesImpl:End");
return status;
}
#endif // ROCKSDB_LITE
Status DBImpl::PauseBackgroundWork() {
InstrumentedMutexLock guard_lock(&mutex_);
bg_compaction_paused_++;
while (bg_bottom_compaction_scheduled_ > 0 || bg_compaction_scheduled_ > 0 ||
bg_flush_scheduled_ > 0) {
bg_cv_.Wait();
}
bg_work_paused_++;
return Status::OK();
}
Status DBImpl::ContinueBackgroundWork() {
InstrumentedMutexLock guard_lock(&mutex_);
if (bg_work_paused_ == 0) {
return Status::InvalidArgument();
}
assert(bg_work_paused_ > 0);
assert(bg_compaction_paused_ > 0);
bg_compaction_paused_--;
bg_work_paused_--;
// It's sufficient to check just bg_work_paused_ here since
// bg_work_paused_ is always no greater than bg_compaction_paused_
if (bg_work_paused_ == 0) {
MaybeScheduleFlushOrCompaction();
}
return Status::OK();
}
void DBImpl::NotifyOnCompactionBegin(ColumnFamilyData* cfd,
Compaction *c, const Status &st,
const CompactionJobStats& job_stats,
int job_id) {
#ifndef ROCKSDB_LITE
if (immutable_db_options_.listeners.empty()) {
return;
}
mutex_.AssertHeld();
if (shutting_down_.load(std::memory_order_acquire)) {
return;
}
Version* current = cfd->current();
current->Ref();
// release lock while notifying events
mutex_.Unlock();
TEST_SYNC_POINT("DBImpl::NotifyOnCompactionBegin::UnlockMutex");
{
CompactionJobInfo info;
info.cf_name = cfd->GetName();
info.status = st;
info.thread_id = env_->GetThreadID();
info.job_id = job_id;
info.base_input_level = c->start_level();
info.output_level = c->output_level();
info.stats = job_stats;
info.table_properties = c->GetOutputTableProperties();
info.compaction_reason = c->compaction_reason();
info.compression = c->output_compression();
for (size_t i = 0; i < c->num_input_levels(); ++i) {
for (const auto fmd : *c->inputs(i)) {
auto fn = TableFileName(c->immutable_cf_options()->cf_paths,
fmd->fd.GetNumber(), fmd->fd.GetPathId());
info.input_files.push_back(fn);
if (info.table_properties.count(fn) == 0) {
std::shared_ptr<const TableProperties> tp;
auto s = current->GetTableProperties(&tp, fmd, &fn);
if (s.ok()) {
info.table_properties[fn] = tp;
}
}
}
}
for (const auto newf : c->edit()->GetNewFiles()) {
info.output_files.push_back(TableFileName(
c->immutable_cf_options()->cf_paths, newf.second.fd.GetNumber(),
newf.second.fd.GetPathId()));
}
for (auto listener : immutable_db_options_.listeners) {
listener->OnCompactionBegin(this, info);
}
}
mutex_.Lock();
current->Unref();
#else
(void)cfd;
(void)c;
(void)st;
(void)job_stats;
(void)job_id;
#endif // ROCKSDB_LITE
}
void DBImpl::NotifyOnCompactionCompleted(
ColumnFamilyData* cfd, Compaction* c, const Status& st,
const CompactionJobStats& compaction_job_stats, const int job_id) {
#ifndef ROCKSDB_LITE
if (immutable_db_options_.listeners.size() == 0U) {
return;
}
mutex_.AssertHeld();
if (shutting_down_.load(std::memory_order_acquire)) {
return;
}
Version* current = cfd->current();
current->Ref();
// release lock while notifying events
mutex_.Unlock();
TEST_SYNC_POINT("DBImpl::NotifyOnCompactionCompleted::UnlockMutex");
{
CompactionJobInfo info;
info.cf_id = cfd->GetID();
info.cf_name = cfd->GetName();
info.status = st;
info.thread_id = env_->GetThreadID();
info.job_id = job_id;
info.base_input_level = c->start_level();
info.output_level = c->output_level();
info.stats = compaction_job_stats;
info.table_properties = c->GetOutputTableProperties();
info.compaction_reason = c->compaction_reason();
info.compression = c->output_compression();
for (size_t i = 0; i < c->num_input_levels(); ++i) {
for (const auto fmd : *c->inputs(i)) {
auto fn = TableFileName(c->immutable_cf_options()->cf_paths,
fmd->fd.GetNumber(), fmd->fd.GetPathId());
info.input_files.push_back(fn);
if (info.table_properties.count(fn) == 0) {
std::shared_ptr<const TableProperties> tp;
auto s = current->GetTableProperties(&tp, fmd, &fn);
if (s.ok()) {
info.table_properties[fn] = tp;
}
}
}
}
for (const auto newf : c->edit()->GetNewFiles()) {
info.output_files.push_back(TableFileName(
c->immutable_cf_options()->cf_paths, newf.second.fd.GetNumber(),
newf.second.fd.GetPathId()));
}
for (auto listener : immutable_db_options_.listeners) {
listener->OnCompactionCompleted(this, info);
}
}
mutex_.Lock();
current->Unref();
// no need to signal bg_cv_ as it will be signaled at the end of the
// flush process.
#else
(void)cfd;
(void)c;
(void)st;
(void)compaction_job_stats;
(void)job_id;
#endif // ROCKSDB_LITE
}
// REQUIREMENT: block all background work by calling PauseBackgroundWork()
// before calling this function
Status DBImpl::ReFitLevel(ColumnFamilyData* cfd, int level, int target_level) {
assert(level < cfd->NumberLevels());
if (target_level >= cfd->NumberLevels()) {
return Status::InvalidArgument("Target level exceeds number of levels");
}
SuperVersionContext sv_context(/* create_superversion */ true);
Status status;
InstrumentedMutexLock guard_lock(&mutex_);
// only allow one thread refitting
if (refitting_level_) {
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"[ReFitLevel] another thread is refitting");
return Status::NotSupported("another thread is refitting");
}
refitting_level_ = true;
const MutableCFOptions mutable_cf_options = *cfd->GetLatestMutableCFOptions();
// move to a smaller level
int to_level = target_level;
if (target_level < 0) {
to_level = FindMinimumEmptyLevelFitting(cfd, mutable_cf_options, level);
}
auto* vstorage = cfd->current()->storage_info();
if (to_level > level) {
if (level == 0) {
return Status::NotSupported(
"Cannot change from level 0 to other levels.");
}
// Check levels are empty for a trivial move
for (int l = level + 1; l <= to_level; l++) {
if (vstorage->NumLevelFiles(l) > 0) {
return Status::NotSupported(
"Levels between source and target are not empty for a move.");
}
}
}
if (to_level != level) {
ROCKS_LOG_DEBUG(immutable_db_options_.info_log,
"[%s] Before refitting:\n%s", cfd->GetName().c_str(),
cfd->current()->DebugString().data());
VersionEdit edit;
edit.SetColumnFamily(cfd->GetID());
for (const auto& f : vstorage->LevelFiles(level)) {
edit.DeleteFile(level, f->fd.GetNumber());
edit.AddFile(to_level, f->fd.GetNumber(), f->fd.GetPathId(),
f->fd.GetFileSize(), f->smallest, f->largest,
f->fd.smallest_seqno, f->fd.largest_seqno,
f->marked_for_compaction);
}
ROCKS_LOG_DEBUG(immutable_db_options_.info_log,
"[%s] Apply version edit:\n%s", cfd->GetName().c_str(),
edit.DebugString().data());
status = versions_->LogAndApply(cfd, mutable_cf_options, &edit, &mutex_,
directories_.GetDbDir());
InstallSuperVersionAndScheduleWork(cfd, &sv_context, mutable_cf_options);
ROCKS_LOG_DEBUG(immutable_db_options_.info_log, "[%s] LogAndApply: %s\n",
cfd->GetName().c_str(), status.ToString().data());
if (status.ok()) {
ROCKS_LOG_DEBUG(immutable_db_options_.info_log,
"[%s] After refitting:\n%s", cfd->GetName().c_str(),
cfd->current()->DebugString().data());
}
}
sv_context.Clean();
refitting_level_ = false;
return status;
}
int DBImpl::NumberLevels(ColumnFamilyHandle* column_family) {
auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
return cfh->cfd()->NumberLevels();
}
int DBImpl::MaxMemCompactionLevel(ColumnFamilyHandle* /*column_family*/) {
return 0;
}
int DBImpl::Level0StopWriteTrigger(ColumnFamilyHandle* column_family) {
auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
InstrumentedMutexLock l(&mutex_);
return cfh->cfd()
->GetSuperVersion()
->mutable_cf_options.level0_stop_writes_trigger;
}
Status DBImpl::Flush(const FlushOptions& flush_options,
ColumnFamilyHandle* column_family) {
auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
ROCKS_LOG_INFO(immutable_db_options_.info_log, "[%s] Manual flush start.",
cfh->GetName().c_str());
Status s;
if (immutable_db_options_.atomic_flush) {
s = AtomicFlushMemTables({cfh->cfd()}, flush_options,
FlushReason::kManualFlush);
} else {
s = FlushMemTable(cfh->cfd(), flush_options, FlushReason::kManualFlush);
}
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"[%s] Manual flush finished, status: %s\n",
cfh->GetName().c_str(), s.ToString().c_str());
return s;
}
Status DBImpl::Flush(const FlushOptions& flush_options,
const std::vector<ColumnFamilyHandle*>& column_families) {
Status s;
if (!immutable_db_options_.atomic_flush) {
for (auto cfh : column_families) {
s = Flush(flush_options, cfh);
if (!s.ok()) {
break;
}
}
} else {
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"Manual atomic flush start.\n"
"=====Column families:=====");
for (auto cfh : column_families) {
auto cfhi = static_cast<ColumnFamilyHandleImpl*>(cfh);
ROCKS_LOG_INFO(immutable_db_options_.info_log, "%s",
cfhi->GetName().c_str());
}
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"=====End of column families list=====");
autovector<ColumnFamilyData*> cfds;
std::for_each(column_families.begin(), column_families.end(),
[&cfds](ColumnFamilyHandle* elem) {
auto cfh = static_cast<ColumnFamilyHandleImpl*>(elem);
cfds.emplace_back(cfh->cfd());
});
s = AtomicFlushMemTables(cfds, flush_options, FlushReason::kManualFlush);
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"Manual atomic flush finished, status: %s\n",
"=====Column families:=====", s.ToString().c_str());
for (auto cfh : column_families) {
auto cfhi = static_cast<ColumnFamilyHandleImpl*>(cfh);
ROCKS_LOG_INFO(immutable_db_options_.info_log, "%s",
cfhi->GetName().c_str());
}
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"=====End of column families list=====");
}
return s;
}
Status DBImpl::RunManualCompaction(ColumnFamilyData* cfd, int input_level,
int output_level, uint32_t output_path_id,
uint32_t max_subcompactions,
const Slice* begin, const Slice* end,
bool exclusive, bool disallow_trivial_move) {
assert(input_level == ColumnFamilyData::kCompactAllLevels ||
input_level >= 0);
InternalKey begin_storage, end_storage;
CompactionArg* ca;
bool scheduled = false;
bool manual_conflict = false;
ManualCompactionState manual;
manual.cfd = cfd;
manual.input_level = input_level;
manual.output_level = output_level;
manual.output_path_id = output_path_id;
manual.done = false;
manual.in_progress = false;
manual.incomplete = false;
manual.exclusive = exclusive;
manual.disallow_trivial_move = disallow_trivial_move;
// For universal compaction, we enforce every manual compaction to compact
// all files.
if (begin == nullptr ||
cfd->ioptions()->compaction_style == kCompactionStyleUniversal ||
cfd->ioptions()->compaction_style == kCompactionStyleFIFO) {
manual.begin = nullptr;
} else {
begin_storage.SetMinPossibleForUserKey(*begin);
manual.begin = &begin_storage;
}
if (end == nullptr ||
cfd->ioptions()->compaction_style == kCompactionStyleUniversal ||
cfd->ioptions()->compaction_style == kCompactionStyleFIFO) {
manual.end = nullptr;
} else {
end_storage.SetMaxPossibleForUserKey(*end);
manual.end = &end_storage;
}
TEST_SYNC_POINT("DBImpl::RunManualCompaction:0");
TEST_SYNC_POINT("DBImpl::RunManualCompaction:1");
InstrumentedMutexLock l(&mutex_);
// When a manual compaction arrives, temporarily disable scheduling of
// non-manual compactions and wait until the number of scheduled compaction
// jobs drops to zero. This is needed to ensure that this manual compaction
// can compact any range of keys/files.
//
// HasPendingManualCompaction() is true when at least one thread is inside
// RunManualCompaction(), i.e. during that time no other compaction will
// get scheduled (see MaybeScheduleFlushOrCompaction).
//
// Note that the following loop doesn't stop more that one thread calling
// RunManualCompaction() from getting to the second while loop below.
// However, only one of them will actually schedule compaction, while
// others will wait on a condition variable until it completes.
AddManualCompaction(&manual);
TEST_SYNC_POINT_CALLBACK("DBImpl::RunManualCompaction:NotScheduled", &mutex_);
if (exclusive) {
while (bg_bottom_compaction_scheduled_ > 0 ||
bg_compaction_scheduled_ > 0) {
TEST_SYNC_POINT("DBImpl::RunManualCompaction:WaitScheduled");
ROCKS_LOG_INFO(
immutable_db_options_.info_log,
"[%s] Manual compaction waiting for all other scheduled background "
"compactions to finish",
cfd->GetName().c_str());
bg_cv_.Wait();
}
}
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"[%s] Manual compaction starting", cfd->GetName().c_str());
// We don't check bg_error_ here, because if we get the error in compaction,
// the compaction will set manual.status to bg_error_ and set manual.done to
// true.
while (!manual.done) {
assert(HasPendingManualCompaction());
manual_conflict = false;
Compaction* compaction = nullptr;
if (ShouldntRunManualCompaction(&manual) || (manual.in_progress == true) ||
scheduled ||
(((manual.manual_end = &manual.tmp_storage1) != nullptr) &&
((compaction = manual.cfd->CompactRange(
*manual.cfd->GetLatestMutableCFOptions(), manual.input_level,
manual.output_level, manual.output_path_id, max_subcompactions,
manual.begin, manual.end, &manual.manual_end,
&manual_conflict)) == nullptr &&
manual_conflict))) {
// exclusive manual compactions should not see a conflict during
// CompactRange
assert(!exclusive || !manual_conflict);
// Running either this or some other manual compaction
bg_cv_.Wait();
if (scheduled && manual.incomplete == true) {
assert(!manual.in_progress);
scheduled = false;
manual.incomplete = false;
}
} else if (!scheduled) {
if (compaction == nullptr) {
manual.done = true;
bg_cv_.SignalAll();
continue;
}
ca = new CompactionArg;
ca->db = this;
ca->prepicked_compaction = new PrepickedCompaction;
ca->prepicked_compaction->manual_compaction_state = &manual;
ca->prepicked_compaction->compaction = compaction;
manual.incomplete = false;
bg_compaction_scheduled_++;
env_->Schedule(&DBImpl::BGWorkCompaction, ca, Env::Priority::LOW, this,
&DBImpl::UnscheduleCallback);
scheduled = true;
}
}
assert(!manual.in_progress);
assert(HasPendingManualCompaction());
RemoveManualCompaction(&manual);
bg_cv_.SignalAll();
return manual.status;
}
void DBImpl::GenerateFlushRequest(const autovector<ColumnFamilyData*>& cfds,
FlushRequest* req) {
assert(req != nullptr);
for (const auto cfd : cfds) {
if (nullptr == cfd) {
// cfd may be null, see DBImpl::ScheduleFlushes
continue;
}
uint64_t max_memtable_id = cfd->imm()->GetLatestMemTableID();
req->emplace_back(cfd, max_memtable_id);
}
}
Status DBImpl::FlushMemTable(ColumnFamilyData* cfd,
const FlushOptions& flush_options,
FlushReason flush_reason, bool writes_stopped) {
Status s;
uint64_t flush_memtable_id = 0;
if (!flush_options.allow_write_stall) {
bool flush_needed = true;
s = WaitUntilFlushWouldNotStallWrites(cfd, &flush_needed);
TEST_SYNC_POINT("DBImpl::FlushMemTable:StallWaitDone");
if (!s.ok() || !flush_needed) {
return s;
}
}
FlushRequest flush_req;
{
WriteContext context;
InstrumentedMutexLock guard_lock(&mutex_);
WriteThread::Writer w;
if (!writes_stopped) {
write_thread_.EnterUnbatched(&w, &mutex_);
}
if (!cfd->mem()->IsEmpty() || !cached_recoverable_state_empty_.load()) {
s = SwitchMemtable(cfd, &context);
}
if (s.ok()) {
if (cfd->imm()->NumNotFlushed() != 0 || !cfd->mem()->IsEmpty() ||
!cached_recoverable_state_empty_.load()) {
flush_memtable_id = cfd->imm()->GetLatestMemTableID();
flush_req.emplace_back(cfd, flush_memtable_id);
}
}
if (s.ok() && !flush_req.empty()) {
for (auto& elem : flush_req) {
ColumnFamilyData* loop_cfd = elem.first;
loop_cfd->imm()->FlushRequested();
}
SchedulePendingFlush(flush_req, flush_reason);
MaybeScheduleFlushOrCompaction();
}
if (!writes_stopped) {
write_thread_.ExitUnbatched(&w);
}
}
if (s.ok() && flush_options.wait) {
autovector<ColumnFamilyData*> cfds;
autovector<const uint64_t*> flush_memtable_ids;
for (auto& iter : flush_req) {
cfds.push_back(iter.first);
flush_memtable_ids.push_back(&(iter.second));
}
s = WaitForFlushMemTables(cfds, flush_memtable_ids,
(flush_reason == FlushReason::kErrorRecovery));
}
TEST_SYNC_POINT("FlushMemTableFinished");
return s;
}
// Flush all elments in 'column_family_datas'
// and atomically record the result to the MANIFEST.
Status DBImpl::AtomicFlushMemTables(
const autovector<ColumnFamilyData*>& column_family_datas,
const FlushOptions& flush_options, FlushReason flush_reason,
bool writes_stopped) {
Status s;
if (!flush_options.allow_write_stall) {
int num_cfs_to_flush = 0;
for (auto cfd : column_family_datas) {
bool flush_needed = true;
s = WaitUntilFlushWouldNotStallWrites(cfd, &flush_needed);
if (!s.ok()) {
return s;
} else if (flush_needed) {
++num_cfs_to_flush;
}
}
if (0 == num_cfs_to_flush) {
return s;
}
}
FlushRequest flush_req;
autovector<ColumnFamilyData*> cfds;
{
WriteContext context;
InstrumentedMutexLock guard_lock(&mutex_);
WriteThread::Writer w;
if (!writes_stopped) {
write_thread_.EnterUnbatched(&w, &mutex_);
}
for (auto cfd : column_family_datas) {
if (cfd->IsDropped()) {
continue;
}
if (cfd->imm()->NumNotFlushed() != 0 || !cfd->mem()->IsEmpty() ||
!cached_recoverable_state_empty_.load()) {
cfds.emplace_back(cfd);
}
}
for (auto cfd : cfds) {
if (cfd->mem()->IsEmpty() && cached_recoverable_state_empty_.load()) {
continue;
}
cfd->Ref();
s = SwitchMemtable(cfd, &context);
cfd->Unref();
if (!s.ok()) {
break;
}
}
if (s.ok()) {
AssignAtomicFlushSeq(cfds);
for (auto cfd : cfds) {
cfd->imm()->FlushRequested();
}
GenerateFlushRequest(cfds, &flush_req);
SchedulePendingFlush(flush_req, flush_reason);
MaybeScheduleFlushOrCompaction();
}
if (!writes_stopped) {
write_thread_.ExitUnbatched(&w);
}
}
TEST_SYNC_POINT("DBImpl::AtomicFlushMemTables:AfterScheduleFlush");
if (s.ok() && flush_options.wait) {
autovector<const uint64_t*> flush_memtable_ids;
for (auto& iter : flush_req) {
flush_memtable_ids.push_back(&(iter.second));
}
s = WaitForFlushMemTables(cfds, flush_memtable_ids,
(flush_reason == FlushReason::kErrorRecovery));
}
return s;
}
// Calling FlushMemTable(), whether from DB::Flush() or from Backup Engine, can
// cause write stall, for example if one memtable is being flushed already.
// This method tries to avoid write stall (similar to CompactRange() behavior)
// it emulates how the SuperVersion / LSM would change if flush happens, checks
// it against various constrains and delays flush if it'd cause write stall.
// Called should check status and flush_needed to see if flush already happened.
Status DBImpl::WaitUntilFlushWouldNotStallWrites(ColumnFamilyData* cfd,
bool* flush_needed) {
{
*flush_needed = true;
InstrumentedMutexLock l(&mutex_);
uint64_t orig_active_memtable_id = cfd->mem()->GetID();
WriteStallCondition write_stall_condition = WriteStallCondition::kNormal;
do {
if (write_stall_condition != WriteStallCondition::kNormal) {
// Same error handling as user writes: Don't wait if there's a
// background error, even if it's a soft error. We might wait here
// indefinitely as the pending flushes/compactions may never finish
// successfully, resulting in the stall condition lasting indefinitely
if (error_handler_.IsBGWorkStopped()) {
return error_handler_.GetBGError();
}
TEST_SYNC_POINT("DBImpl::WaitUntilFlushWouldNotStallWrites:StallWait");
ROCKS_LOG_INFO(immutable_db_options_.info_log,
"[%s] WaitUntilFlushWouldNotStallWrites"
" waiting on stall conditions to clear",
cfd->GetName().c_str());
bg_cv_.Wait();
}
if (cfd->IsDropped() || shutting_down_.load(std::memory_order_acquire)) {
return Status::ShutdownInProgress();
}
uint64_t earliest_memtable_id =
std::min(cfd->mem()->GetID(), cfd->imm()->GetEarliestMemTableID());
if (earliest_memtable_id > orig_active_memtable_id) {
// We waited so long that the memtable we were originally waiting on was
// flushed.
*flush_needed = false;
return Status::OK();
}
const auto& mutable_cf_options = *cfd->GetLatestMutableCFOptions();
const auto* vstorage = cfd->current()->storage_info();
// Skip stalling check if we're below auto-flush and auto-compaction
// triggers. If it stalled in these conditions, that'd mean the stall
// triggers are so low that stalling is needed for any background work. In
// that case we shouldn't wait since background work won't be scheduled.
if (cfd->imm()->NumNotFlushed() <
cfd->ioptions()->min_write_buffer_number_to_merge &&
vstorage->l0_delay_trigger_count() <
mutable_cf_options.level0_file_num_compaction_trigger) {
break;
}
// check whether one extra immutable memtable or an extra L0 file would
// cause write stalling mode to be entered. It could still enter stall
// mode due to pending compaction bytes, but that's less common
write_stall_condition =
ColumnFamilyData::GetWriteStallConditionAndCause(
cfd->imm()->NumNotFlushed() + 1,
vstorage->l0_delay_trigger_count() + 1,
vstorage->estimated_compaction_needed_bytes(), mutable_cf_options)
.first;
} while (write_stall_condition != WriteStallCondition::kNormal);
}
return Status::OK();
}
// Wait for memtables to be flushed for multiple column families.
// let N = cfds.size()
// for i in [0, N),
// 1) if flush_memtable_ids[i] is not null, then the memtables with lower IDs
// have to be flushed for THIS column family;
// 2) if flush_memtable_ids[i] is null, then all memtables in THIS column
// family have to be flushed.
// Finish waiting when ALL column families finish flushing memtables.
// resuming_from_bg_err indicates whether the caller is trying to resume from
// background error or in normal processing.
Status DBImpl::WaitForFlushMemTables(
const autovector<ColumnFamilyData*>& cfds,
const autovector<const uint64_t*>& flush_memtable_ids,
bool resuming_from_bg_err) {
int num = static_cast<int>(cfds.size());
// Wait until the compaction completes
InstrumentedMutexLock l(&mutex_);
// If the caller is trying to resume from bg error, then
// error_handler_.IsDBStopped() is true.
while (resuming_from_bg_err || !error_handler_.IsDBStopped()) {
if (shutting_down_.load(std::memory_order_acquire)) {
return Status::ShutdownInProgress();
}
// If an error has occurred during resumption, then no need to wait.
if (!error_handler_.GetRecoveryError().ok()) {
break;
}
// Number of column families that have been dropped.
int num_dropped = 0;
// Number of column families that have finished flush.
int num_finished = 0;
for (int i = 0; i < num; ++i) {
if (cfds[i]->IsDropped()) {
++num_dropped;
} else if (cfds[i]->imm()->NumNotFlushed() == 0 ||
(flush_memtable_ids[i] != nullptr &&
cfds[i]->imm()->GetEarliestMemTableID() >
*flush_memtable_ids[i])) {
++num_finished;
}
}
if (1 == num_dropped && 1 == num) {
return Status::InvalidArgument("Cannot flush a dropped CF");
}
// Column families involved in this flush request have either been dropped
// or finished flush. Then it's time to finish waiting.
if (num_dropped + num_finished == num) {
break;
}
bg_cv_.Wait();
}
Status s;
// If not resuming from bg error, and an error has caused the DB to stop,
// then report the bg error to caller.
if (!resuming_from_bg_err && error_handler_.IsDBStopped()) {
s = error_handler_.GetBGError();
}
return s;
}
Status DBImpl::EnableAutoCompaction(
const std::vector<ColumnFamilyHandle*>& column_family_handles) {
Status s;
for (auto cf_ptr : column_family_handles) {
Status status =
this->SetOptions(cf_ptr, {{"disable_auto_compactions", "false"}});
if (!status.ok()) {
s = status;
}
}
return s;
}
void DBImpl::MaybeScheduleFlushOrCompaction() {
mutex_.AssertHeld();
if (!opened_successfully_) {
// Compaction may introduce data race to DB open
return;
}
if (bg_work_paused_ > 0) {
// we paused the background work
return;
} else if (error_handler_.IsBGWorkStopped() &&
!error_handler_.IsRecoveryInProgress()) {
// There has been a hard error and this call is not part of the recovery
// sequence. Bail out here so we don't get into an endless loop of
// scheduling BG work which will again call this function
return;
} else if (shutting_down_.load(std::memory_order_acquire)) {
// DB is being deleted; no more background compactions
return;
}
auto bg_job_limits = GetBGJobLimits();
bool is_flush_pool_empty =
env_->GetBackgroundThreads(Env::Priority::HIGH) == 0;
while (!is_flush_pool_empty && unscheduled_flushes_ > 0 &&
bg_flush_scheduled_ < bg_job_limits.max_flushes) {
bg_flush_scheduled_++;
env_->Schedule(&DBImpl::BGWorkFlush, this, Env::Priority::HIGH, this);
}
// special case -- if high-pri (flush) thread pool is empty, then schedule
// flushes in low-pri (compaction) thread pool.
if (is_flush_pool_empty) {
while (unscheduled_flushes_ > 0 &&
bg_flush_scheduled_ + bg_compaction_scheduled_ <
bg_job_limits.max_flushes) {
bg_flush_scheduled_++;
env_->Schedule(&DBImpl::BGWorkFlush, this, Env::Priority::LOW, this);
}
}
if (bg_compaction_paused_ > 0) {
// we paused the background compaction
return;
} else if (error_handler_.IsBGWorkStopped()) {
// Compaction is not part of the recovery sequence from a hard error. We
// might get here because recovery might do a flush and install a new
// super version, which will try to schedule pending compactions. Bail
// out here and let the higher level recovery handle compactions
return;
}
if (HasExclusiveManualCompaction()) {
// only manual compactions are allowed to run. don't schedule automatic
// compactions
TEST_SYNC_POINT("DBImpl::MaybeScheduleFlushOrCompaction:Conflict");
return;
}
while (bg_compaction_scheduled_ < bg_job_limits.max_compactions &&
unscheduled_compactions_ > 0) {
CompactionArg* ca = new CompactionArg;
ca->db = this;
ca->prepicked_compaction = nullptr;
bg_compaction_scheduled_++;
unscheduled_compactions_--;
env_->Schedule(&DBImpl::BGWorkCompaction, ca, Env::Priority::LOW, this,
&DBImpl::UnscheduleCallback);
}
}
DBImpl::BGJobLimits DBImpl::GetBGJobLimits() const {
mutex_.AssertHeld();
return GetBGJobLimits(immutable_db_options_.max_background_flushes,
mutable_db_options_.max_background_compactions,
mutable_db_options_.max_background_jobs,
write_controller_.NeedSpeedupCompaction());
}
DBImpl::BGJobLimits DBImpl::GetBGJobLimits(int max_background_flushes,
int max_background_compactions,
int max_background_jobs,
bool parallelize_compactions) {
BGJobLimits res;
if (max_background_flushes == -1 && max_background_compactions == -1) {
// for our first stab implementing max_background_jobs, simply allocate a
// quarter of the threads to flushes.
res.max_flushes = std::max(1, max_background_jobs / 4);
res.max_compactions = std::max(1, max_background_jobs - res.max_flushes);
} else {
// compatibility code in case users haven't migrated to max_background_jobs,
// which automatically computes flush/compaction limits
res.max_flushes = std::max(1, max_background_flushes);
res.max_compactions = std::max(1, max_background_compactions);
}
if (!parallelize_compactions) {
// throttle background compactions until we deem necessary
res.max_compactions = 1;
}
return res;
}
void DBImpl::AddToCompactionQueue(ColumnFamilyData* cfd) {
assert(!cfd->queued_for_compaction());
cfd->Ref();
compaction_queue_.push_back(cfd);
cfd->set_queued_for_compaction(true);
}
ColumnFamilyData* DBImpl::PopFirstFromCompactionQueue() {
assert(!compaction_queue_.empty());
auto cfd = *compaction_queue_.begin();
compaction_queue_.pop_front();
assert(cfd->queued_for_compaction());
cfd->set_queued_for_compaction(false);
return cfd;
}
DBImpl::FlushRequest DBImpl::PopFirstFromFlushQueue() {
assert(!flush_queue_.empty());
FlushRequest flush_req = flush_queue_.front();
assert(unscheduled_flushes_ >= static_cast<int>(flush_req.size()));
unscheduled_flushes_ -= static_cast<int>(flush_req.size());
flush_queue_.pop_front();
// TODO: need to unset flush reason?
return flush_req;
}
void DBImpl::SchedulePendingFlush(const FlushRequest& flush_req,
FlushReason flush_reason) {
if (flush_req.empty()) {
return;
}
for (auto& iter : flush_req) {
ColumnFamilyData* cfd = iter.first;
cfd->Ref();
cfd->SetFlushReason(flush_reason);
}
unscheduled_flushes_ += static_cast<int>(flush_req.size());
flush_queue_.push_back(flush_req);
}
void DBImpl::SchedulePendingCompaction(ColumnFamilyData* cfd) {
if (!cfd->queued_for_compaction() && cfd->NeedsCompaction()) {
AddToCompactionQueue(cfd);
++unscheduled_compactions_;
}
}
void DBImpl::SchedulePendingPurge(std::string fname, std::string dir_to_sync,
FileType type, uint64_t number, int job_id) {
mutex_.AssertHeld();
PurgeFileInfo file_info(fname, dir_to_sync, type, number, job_id);
purge_queue_.push_back(std::move(file_info));
}
void DBImpl::BGWorkFlush(void* db) {
IOSTATS_SET_THREAD_POOL_ID(Env::Priority::HIGH);
TEST_SYNC_POINT("DBImpl::BGWorkFlush");
reinterpret_cast<DBImpl*>(db)->BackgroundCallFlush();
TEST_SYNC_POINT("DBImpl::BGWorkFlush:done");
}
void DBImpl::BGWorkCompaction(void* arg) {
CompactionArg ca = *(reinterpret_cast<CompactionArg*>(arg));
delete reinterpret_cast<CompactionArg*>(arg);
IOSTATS_SET_THREAD_POOL_ID(Env::Priority::LOW);
TEST_SYNC_POINT("DBImpl::BGWorkCompaction");
auto prepicked_compaction =
static_cast<PrepickedCompaction*>(ca.prepicked_compaction);
reinterpret_cast<DBImpl*>(ca.db)->BackgroundCallCompaction(
prepicked_compaction, Env::Priority::LOW);
delete prepicked_compaction;
}
void DBImpl::BGWorkBottomCompaction(void* arg) {
CompactionArg ca = *(static_cast<CompactionArg*>(arg));
delete static_cast<CompactionArg*>(arg);
IOSTATS_SET_THREAD_POOL_ID(Env::Priority::BOTTOM);
TEST_SYNC_POINT("DBImpl::BGWorkBottomCompaction");
auto* prepicked_compaction = ca.prepicked_compaction;
assert(prepicked_compaction && prepicked_compaction->compaction &&
!prepicked_compaction->manual_compaction_state);
ca.db->BackgroundCallCompaction(prepicked_compaction, Env::Priority::BOTTOM);
delete prepicked_compaction;
}
void DBImpl::BGWorkPurge(void* db) {
IOSTATS_SET_THREAD_POOL_ID(Env::Priority::HIGH);
TEST_SYNC_POINT("DBImpl::BGWorkPurge:start");
reinterpret_cast<DBImpl*>(db)->BackgroundCallPurge();
TEST_SYNC_POINT("DBImpl::BGWorkPurge:end");
}
void DBImpl::UnscheduleCallback(void* arg) {
CompactionArg ca = *(reinterpret_cast<CompactionArg*>(arg));
delete reinterpret_cast<CompactionArg*>(arg);
if (ca.prepicked_compaction != nullptr) {
if (ca.prepicked_compaction->compaction != nullptr) {
delete ca.prepicked_compaction->compaction;
}
delete ca.prepicked_compaction;
}
TEST_SYNC_POINT("DBImpl::UnscheduleCallback");
}
Status DBImpl::BackgroundFlush(bool* made_progress, JobContext* job_context,
LogBuffer* log_buffer, FlushReason* reason) {
mutex_.AssertHeld();
Status status;
*reason = FlushReason::kOthers;
// If BG work is stopped due to an error, but a recovery is in progress,
// that means this flush is part of the recovery. So allow it to go through
if (!error_handler_.IsBGWorkStopped()) {
if (shutting_down_.load(std::memory_order_acquire)) {
status = Status::ShutdownInProgress();
}
} else if (!error_handler_.IsRecoveryInProgress()) {
status = error_handler_.GetBGError();
}
if (!status.ok()) {
return status;
}
autovector<BGFlushArg> bg_flush_args;
std::vector<SuperVersionContext>& superversion_contexts =
job_context->superversion_contexts;
while (!flush_queue_.empty()) {
// This cfd is already referenced
const FlushRequest& flush_req = PopFirstFromFlushQueue();
superversion_contexts.clear();
superversion_contexts.reserve(flush_req.size());
for (const auto& iter : flush_req) {
ColumnFamilyData* cfd = iter.first;
if (cfd->IsDropped() || !cfd->imm()->IsFlushPending()) {
// can't flush this CF, try next one
if (cfd->Unref()) {
delete cfd;
}
continue;
}
superversion_contexts.emplace_back(SuperVersionContext(true));
bg_flush_args.emplace_back(cfd, iter.second,
&(superversion_contexts.back()));
}
if (!bg_flush_args.empty()) {
break;
}
}
if (!bg_flush_args.empty()) {
auto bg_job_limits = GetBGJobLimits();
for (const auto& arg : bg_flush_args) {
ColumnFamilyData* cfd = arg.cfd_;
ROCKS_LOG_BUFFER(
log_buffer,
"Calling FlushMemTableToOutputFile with column "
"family [%s], flush slots available %d, compaction slots available "
"%d, "
"flush slots scheduled %d, compaction slots scheduled %d",
cfd->GetName().c_str(), bg_job_limits.max_flushes,
bg_job_limits.max_compactions, bg_flush_scheduled_,
bg_compaction_scheduled_);
}
status = FlushMemTablesToOutputFiles(bg_flush_args, made_progress,
job_context, log_buffer);
// All the CFDs in the FlushReq must have the same flush reason, so just
// grab the first one
*reason = bg_flush_args[0].cfd_->GetFlushReason();
for (auto& arg : bg_flush_args) {
ColumnFamilyData* cfd = arg.cfd_;
if (cfd->Unref()) {
delete cfd;
arg.cfd_ = nullptr;
}
}
}
return status;
}
void DBImpl::BackgroundCallFlush() {
bool made_progress = false;
JobContext job_context(next_job_id_.fetch_add(1), true);
TEST_SYNC_POINT("DBImpl::BackgroundCallFlush:start");
LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL,
immutable_db_options_.info_log.get());
{
InstrumentedMutexLock l(&mutex_);
assert(bg_flush_scheduled_);
num_running_flushes_++;
auto pending_outputs_inserted_elem =
CaptureCurrentFileNumberInPendingOutputs();
FlushReason reason;
Status s =
BackgroundFlush(&made_progress, &job_context, &log_buffer, &reason);
if (!s.ok() && !s.IsShutdownInProgress() &&
reason != FlushReason::kErrorRecovery) {
// Wait a little bit before retrying background flush in
// case this is an environmental problem and we do not want to
// chew up resources for failed flushes for the duration of
// the problem.
uint64_t error_cnt =
default_cf_internal_stats_->BumpAndGetBackgroundErrorCount();
bg_cv_.SignalAll(); // In case a waiter can proceed despite the error
mutex_.Unlock();
ROCKS_LOG_ERROR(immutable_db_options_.info_log,
"Waiting after background flush error: %s"
"Accumulated background error counts: %" PRIu64,
s.ToString().c_str(), error_cnt);
log_buffer.FlushBufferToLog();
LogFlush(immutable_db_options_.info_log);
env_->SleepForMicroseconds(1000000);
mutex_.Lock();
}
TEST_SYNC_POINT("DBImpl::BackgroundCallFlush:FlushFinish:0");
ReleaseFileNumberFromPendingOutputs(pending_outputs_inserted_elem);
// If flush failed, we want to delete all temporary files that we might have
// created. Thus, we force full scan in FindObsoleteFiles()
FindObsoleteFiles(&job_context, !s.ok() && !s.IsShutdownInProgress());
// delete unnecessary files if any, this is done outside the mutex
if (job_context.HaveSomethingToClean() ||
job_context.HaveSomethingToDelete() || !log_buffer.IsEmpty()) {
mutex_.Unlock();
TEST_SYNC_POINT("DBImpl::BackgroundCallFlush:FilesFound");
// Have to flush the info logs before bg_flush_scheduled_--
// because if bg_flush_scheduled_ becomes 0 and the lock is
// released, the deconstructor of DB can kick in and destroy all the
// states of DB so info_log might not be available after that point.
// It also applies to access other states that DB owns.
log_buffer.FlushBufferToLog();
if (job_context.HaveSomethingToDelete()) {
PurgeObsoleteFiles(job_context);
}
job_context.Clean();
mutex_.Lock();
}
TEST_SYNC_POINT("DBImpl::BackgroundCallFlush:ContextCleanedUp");
assert(num_running_flushes_ > 0);
num_running_flushes_--;
bg_flush_scheduled_--;
// See if there's more work to be done
MaybeScheduleFlushOrCompaction();
bg_cv_.SignalAll();
// IMPORTANT: there should be no code after calling SignalAll. This call may
// signal the DB destructor that it's OK to proceed with destruction. In
// that case, all DB variables will be dealloacated and referencing them
// will cause trouble.
}
}
void DBImpl::BackgroundCallCompaction(PrepickedCompaction* prepicked_compaction,
Env::Priority bg_thread_pri) {
bool made_progress = false;
JobContext job_context(next_job_id_.fetch_add(1), true);
TEST_SYNC_POINT("BackgroundCallCompaction:0");
LogBuffer log_buffer(InfoLogLevel::INFO_LEVEL,
immutable_db_options_.info_log.get());
{
InstrumentedMutexLock l(&mutex_);
// This call will unlock/lock the mutex to wait for current running
// IngestExternalFile() calls to finish.
WaitForIngestFile();
num_running_compactions_++;
auto pending_outputs_inserted_elem =
CaptureCurrentFileNumberInPendingOutputs();
assert((bg_thread_pri == Env::Priority::BOTTOM &&
bg_bottom_compaction_scheduled_) ||
(bg_thread_pri == Env::Priority::LOW && bg_compaction_scheduled_));
Status s = BackgroundCompaction(&made_progress, &job_context, &log_buffer,
prepicked_compaction);
TEST_SYNC_POINT("BackgroundCallCompaction:1");
if (!s.ok() && !s.IsShutdownInProgress()) {
// Wait a little bit before retrying background compaction in
// case this is an environmental problem and we do not want to
// chew up resources for failed compactions for the duration of
// the problem.
uint64_t error_cnt =
default_cf_internal_stats_->BumpAndGetBackgroundErrorCount();
bg_cv_.SignalAll(); // In case a waiter can proceed despite the error
mutex_.Unlock();
log_buffer.FlushBufferToLog();
ROCKS_LOG_ERROR(immutable_db_options_.info_log,
"Waiting after background compaction error: %s, "
"Accumulated background error counts: %" PRIu64,
s.ToString().c_str(), error_cnt);
LogFlush(immutable_db_options_.info_log);
env_->SleepForMicroseconds(1000000);
mutex_.Lock();
}
ReleaseFileNumberFromPendingOutputs(pending_outputs_inserted_elem);
// If compaction failed, we want to delete all temporary files that we might
// have created (they might not be all recorded in job_context in case of a
// failure). Thus, we force full scan in FindObsoleteFiles()
FindObsoleteFiles(&job_context, !s.ok() && !s.IsShutdownInProgress());
TEST_SYNC_POINT("DBImpl::BackgroundCallCompaction:FoundObsoleteFiles");
// delete unnecessary files if any, this is done outside the mutex
if (job_context.HaveSomethingToClean() ||
job_context.HaveSomethingToDelete() || !log_buffer.IsEmpty()) {
mutex_.Unlock();
// Have to flush the info logs before bg_compaction_scheduled_--
// because if bg_flush_scheduled_ becomes 0 and the lock is
// released, the deconstructor of DB can kick in and destroy all the
// states of DB so info_log might not be available after that point.
// It also applies to access other states that DB owns.
log_buffer.FlushBufferToLog();
if (job_context.HaveSomethingToDelete()) {
PurgeObsoleteFiles(job_context);
TEST_SYNC_POINT("DBImpl::BackgroundCallCompaction:PurgedObsoleteFiles");
}
job_context.Clean();
mutex_.Lock();
}
assert(num_running_compactions_ > 0);
num_running_compactions_--;
if (bg_thread_pri == Env::Priority::LOW) {
bg_compaction_scheduled_--;
} else {
assert(bg_thread_pri == Env::Priority::BOTTOM);
bg_bottom_compaction_scheduled_--;
}
versions_->GetColumnFamilySet()->FreeDeadColumnFamilies();
// See if there's more work to be done
MaybeScheduleFlushOrCompaction();
if (made_progress ||
(bg_compaction_scheduled_ == 0 &&
bg_bottom_compaction_scheduled_ == 0) ||
HasPendingManualCompaction() || unscheduled_compactions_ == 0) {
// signal if
// * made_progress -- need to wakeup DelayWrite
// * bg_{bottom,}_compaction_scheduled_ == 0 -- need to wakeup ~DBImpl
// * HasPendingManualCompaction -- need to wakeup RunManualCompaction
// If none of this is true, there is no need to signal since nobody is
// waiting for it
bg_cv_.SignalAll();
}
// IMPORTANT: there should be no code after calling SignalAll. This call may
// signal the DB destructor that it's OK to proceed with destruction. In
// that case, all DB variables will be dealloacated and referencing them
// will cause trouble.
}
}
Status DBImpl::BackgroundCompaction(bool* made_progress,
JobContext* job_context,
LogBuffer* log_buffer,
PrepickedCompaction* prepicked_compaction) {
ManualCompactionState* manual_compaction =
prepicked_compaction == nullptr
? nullptr
: prepicked_compaction->manual_compaction_state;
*made_progress = false;
mutex_.AssertHeld();
TEST_SYNC_POINT("DBImpl::BackgroundCompaction:Start");
bool is_manual = (manual_compaction != nullptr);
std::unique_ptr<Compaction> c;
if (prepicked_compaction != nullptr &&
prepicked_compaction->compaction != nullptr) {
c.reset(prepicked_compaction->compaction);
}
bool is_prepicked = is_manual || c;
// (manual_compaction->in_progress == false);
bool trivial_move_disallowed =
is_manual && manual_compaction->disallow_trivial_move;
CompactionJobStats compaction_job_stats;
Status status;
if (!error_handler_.IsBGWorkStopped()) {
if (shutting_down_.load(std::memory_order_acquire)) {
status = Status::ShutdownInProgress();
}
} else {
status = error_handler_.GetBGError();
// If we get here, it means a hard error happened after this compaction
// was scheduled by MaybeScheduleFlushOrCompaction(), but before it got
// a chance to execute. Since we didn't pop a cfd from the compaction
// queue, increment unscheduled_compactions_
unscheduled_compactions_++;
}
if (!status.ok()) {
if (is_manual) {
manual_compaction->status = status;
manual_compaction->done = true;
manual_compaction->in_progress = false;
manual_compaction = nullptr;
}
if (c) {
c->ReleaseCompactionFiles(status);
c.reset();
}
return status;
}
if (is_manual) {
// another thread cannot pick up the same work
manual_compaction->in_progress = true;
}
// InternalKey manual_end_storage;
// InternalKey* manual_end = &manual_end_storage;
bool sfm_reserved_compact_space = false;
if (is_manual) {
ManualCompactionState* m = manual_compaction;
assert(m->in_progress);
if (!c) {
m->done = true;
m->manual_end = nullptr;
ROCKS_LOG_BUFFER(log_buffer,
"[%s] Manual compaction from level-%d from %s .. "
"%s; nothing to do\n",
m->cfd->GetName().c_str(), m->input_level,
(m->begin ? m->begin->DebugString().c_str() : "(begin)"),
(m->end ? m->end->DebugString().c_str() : "(end)"));
} else {
// First check if we have enough room to do the compaction
bool enough_room = EnoughRoomForCompaction(
m->cfd, *(c->inputs()), &sfm_reserved_compact_space, log_buffer);
if (!enough_room) {
// Then don't do the compaction
c->ReleaseCompactionFiles(status);
c.reset();
// m's vars will get set properly at the end of this function,
// as long as status == CompactionTooLarge
status = Status::CompactionTooLarge();
} else {
ROCKS_LOG_BUFFER(
log_buffer,
"[%s] Manual compaction from level-%d to level-%d from %s .. "
"%s; will stop at %s\n",
m->cfd->GetName().c_str(), m->input_level, c->output_level(),
(m->begin ? m->begin->DebugString().c_str() : "(begin)"),
(m->end ? m->end->DebugString().c_str() : "(end)"),
((m->done || m->manual_end == nullptr)
? "(end)"
: m->manual_end->DebugString().c_str()));
}
}
} else if (!is_prepicked && !compaction_queue_.empty()) {
if (HasExclusiveManualCompaction()) {
// Can't compact right now, but try again later
TEST_SYNC_POINT("DBImpl::BackgroundCompaction()::Conflict");
// Stay in the compaction queue.
unscheduled_compactions_++;
return Status::OK();
}
// cfd is referenced here
auto cfd = PopFirstFromCompactionQueue();
// We unreference here because the following code will take a Ref() on
// this cfd if it is going to use it (Compaction class holds a
// reference).
// This will all happen under a mutex so we don't have to be afraid of
// somebody else deleting it.
if (cfd->Unref()) {
delete cfd;
// This was the last reference of the column family, so no need to
// compact.
return Status::OK();
}
// Pick up latest mutable CF Options and use it throughout the
// compaction job
// Compaction makes a copy of the latest MutableCFOptions. It should be used
// throughout the compaction procedure to make sure consistency. It will
// eventually be installed into SuperVersion
auto* mutable_cf_options = cfd->GetLatestMutableCFOptions();
if (!mutable_cf_options->disable_auto_compactions && !cfd->IsDropped()) {
// NOTE: try to avoid unnecessary copy of MutableCFOptions if
// compaction is not necessary. Need to make sure mutex is held
// until we make a copy in the following code
TEST_SYNC_POINT("DBImpl::BackgroundCompaction():BeforePickCompaction");
c.reset(cfd->PickCompaction(*mutable_cf_options, log_buffer));
TEST_SYNC_POINT("DBImpl::BackgroundCompaction():AfterPickCompaction");
if (c != nullptr) {
bool enough_room = EnoughRoomForCompaction(
cfd, *(c->inputs()), &sfm_reserved_compact_space, log_buffer);
if (!enough_room) {
// Then don't do the compaction
c->ReleaseCompactionFiles(status);
c->column_family_data()
->current()
->storage_info()
->ComputeCompactionScore(*(c->immutable_cf_options()),
*(c->mutable_cf_options()));
AddToCompactionQueue(cfd);
++unscheduled_compactions_;
c.reset();
// Don't need to sleep here, because BackgroundCallCompaction
// will sleep if !s.ok()
status = Status::CompactionTooLarge();
} else {
// update statistics
MeasureTime(stats_, NUM_FILES_IN_SINGLE_COMPACTION,
c->inputs(0)->size());
// There are three things that can change compaction score:
// 1) When flush or compaction finish. This case is covered by
// InstallSuperVersionAndScheduleWork
// 2) When MutableCFOptions changes. This case is also covered by
// InstallSuperVersionAndScheduleWork, because this is when the new
// options take effect.
// 3) When we Pick a new compaction, we "remove" those files being
// compacted from the calculation, which then influences compaction
// score. Here we check if we need the new compaction even without the
// files that are currently being compacted. If we need another
// compaction, we might be able to execute it in parallel, so we add
// it to the queue and schedule a new thread.
if (cfd->NeedsCompaction()) {
// Yes, we need more compactions!
AddToCompactionQueue(cfd);
++unscheduled_compactions_;
MaybeScheduleFlushOrCompaction();
}
}
}
}
}
if (!c) {
// Nothing to do
ROCKS_LOG_BUFFER(log_buffer, "Compaction nothing to do");
} else if (c->deletion_compaction()) {
// TODO(icanadi) Do we want to honor snapshots here? i.e. not delete old
// file if there is alive snapshot pointing to it
assert(c->num_input_files(1) == 0);
assert(c->level() == 0);
assert(c->column_family_data()->ioptions()->compaction_style ==
kCompactionStyleFIFO);
compaction_job_stats.num_input_files = c->num_input_files(0);
NotifyOnCompactionBegin(c->column_family_data(), c.get(), status,
compaction_job_stats, job_context->job_id);
for (const auto& f : *c->inputs(0)) {
c->edit()->DeleteFile(c->level(), f->fd.GetNumber());
}
status = versions_->LogAndApply(c->column_family_data(),
*c->mutable_cf_options(), c->edit(),
&mutex_, directories_.GetDbDir());
InstallSuperVersionAndScheduleWork(
c->column_family_data(), &job_context->superversion_contexts[0],
*c->mutable_cf_options(), FlushReason::kAutoCompaction);
ROCKS_LOG_BUFFER(log_buffer, "[%s] Deleted %d files\n",
c->column_family_data()->GetName().c_str(),
c->num_input_files(0));
*made_progress = true;
} else if (!trivial_move_disallowed && c->IsTrivialMove()) {
TEST_SYNC_POINT("DBImpl::BackgroundCompaction:TrivialMove");
// Instrument for event update
// TODO(yhchiang): add op details for showing trivial-move.
ThreadStatusUtil::SetColumnFamily(
c->column_family_data(), c->column_family_data()->ioptions()->env,
immutable_db_options_.enable_thread_tracking);
ThreadStatusUtil::SetThreadOperation(ThreadStatus::OP_COMPACTION);
compaction_job_stats.num_input_files = c->num_input_files(0);
NotifyOnCompactionBegin(c->column_family_data(), c.get(), status,
compaction_job_stats, job_context->job_id);
// Move files to next level
int32_t moved_files = 0;
int64_t moved_bytes = 0;
for (unsigned int l = 0; l < c->num_input_levels(); l++) {
if (c->level(l) == c->output_level()) {
continue;
}
for (size_t i = 0; i < c->num_input_files(l); i++) {
FileMetaData* f = c->input(l, i);
c->edit()->DeleteFile(c->level(l), f->fd.GetNumber());
c->edit()->AddFile(c->output_level(), f->fd.GetNumber(),
f->fd.GetPathId(), f->fd.GetFileSize(), f->smallest,
f->largest, f->fd.smallest_seqno,
f->fd.largest_seqno, f->marked_for_compaction);
ROCKS_LOG_BUFFER(
log_buffer,
"[%s] Moving #%" PRIu64 " to level-%d %" PRIu64 " bytes\n",
c->column_family_data()->GetName().c_str(), f->fd.GetNumber(),
c->output_level(), f->fd.GetFileSize());
++moved_files;
moved_bytes += f->fd.GetFileSize();
}
}
status = versions_->LogAndApply(c->column_family_data(),
*c->mutable_cf_options(), c->edit(),
&mutex_, directories_.GetDbDir());
// Use latest MutableCFOptions
InstallSuperVersionAndScheduleWork(
c->column_family_data(), &job_context->superversion_contexts[0],
*c->mutable_cf_options(), FlushReason::kAutoCompaction);
VersionStorageInfo::LevelSummaryStorage tmp;
c->column_family_data()->internal_stats()->IncBytesMoved(c->output_level(),
moved_bytes);
{
event_logger_.LogToBuffer(log_buffer)
<< "job" << job_context->job_id << "event"
<< "trivial_move"
<< "destination_level" << c->output_level() << "files" << moved_files
<< "total_files_size" << moved_bytes;
}
ROCKS_LOG_BUFFER(
log_buffer,
"[%s] Moved #%d files to level-%d %" PRIu64 " bytes %s: %s\n",
c->column_family_data()->GetName().c_str(), moved_files,
c->output_level(), moved_bytes, status.ToString().c_str(),
c->column_family_data()->current()->storage_info()->LevelSummary(&tmp));
*made_progress = true;
// Clear Instrument
ThreadStatusUtil::ResetThreadStatus();
} else if (!is_prepicked && c->output_level() > 0 &&
c->output_level() ==
c->column_family_data()
->current()
->storage_info()
->MaxOutputLevel(
immutable_db_options_.allow_ingest_behind) &&
env_->GetBackgroundThreads(Env::Priority::BOTTOM) > 0) {
// Forward compactions involving last level to the bottom pool if it exists,
// such that compactions unlikely to contribute to write stalls can be
// delayed or deprioritized.
TEST_SYNC_POINT("DBImpl::BackgroundCompaction:ForwardToBottomPriPool");
CompactionArg* ca = new CompactionArg;
ca->db = this;
ca->prepicked_compaction = new PrepickedCompaction;
ca->prepicked_compaction->compaction = c.release();
ca->prepicked_compaction->manual_compaction_state = nullptr;
++bg_bottom_compaction_scheduled_;
env_->Schedule(&DBImpl::BGWorkBottomCompaction, ca, Env::Priority::BOTTOM,
this, &DBImpl::UnscheduleCallback);
} else {
int output_level __attribute__((__unused__));
output_level = c->output_level();
TEST_SYNC_POINT_CALLBACK("DBImpl::BackgroundCompaction:NonTrivial",
&output_level);
SequenceNumber earliest_write_conflict_snapshot;
std::vector<SequenceNumber> snapshot_seqs =
snapshots_.GetAll(&earliest_write_conflict_snapshot);
auto snapshot_checker = snapshot_checker_.get();
if (use_custom_gc_ && snapshot_checker == nullptr) {
snapshot_checker = DisableGCSnapshotChecker::Instance();
}
assert(is_snapshot_supported_ || snapshots_.empty());
CompactionJob compaction_job(
job_context->job_id, c.get(), immutable_db_options_,
env_options_for_compaction_, versions_.get(), &shutting_down_,
preserve_deletes_seqnum_.load(), log_buffer, directories_.GetDbDir(),
GetDataDir(c->column_family_data(), c->output_path_id()), stats_,
&mutex_, &error_handler_, snapshot_seqs, earliest_write_conflict_snapshot,
snapshot_checker, table_cache_, &event_logger_,
c->mutable_cf_options()->paranoid_file_checks,
c->mutable_cf_options()->report_bg_io_stats, dbname_,
&compaction_job_stats);
compaction_job.Prepare();
NotifyOnCompactionBegin(c->column_family_data(), c.get(), status,
compaction_job_stats, job_context->job_id);
mutex_.Unlock();
compaction_job.Run();
TEST_SYNC_POINT("DBImpl::BackgroundCompaction:NonTrivial:AfterRun");
mutex_.Lock();
status = compaction_job.Install(*c->mutable_cf_options());
if (status.ok()) {
InstallSuperVersionAndScheduleWork(
c->column_family_data(), &job_context->superversion_contexts[0],
*c->mutable_cf_options(), FlushReason::kAutoCompaction);
}
*made_progress = true;
}
if (c != nullptr) {
c->ReleaseCompactionFiles(status);
*made_progress = true;
#ifndef ROCKSDB_LITE
// Need to make sure SstFileManager does its bookkeeping
auto sfm = static_cast<SstFileManagerImpl*>(
immutable_db_options_.sst_file_manager.get());
if (sfm && sfm_reserved_compact_space) {
sfm->OnCompactionCompletion(c.get());
}
#endif // ROCKSDB_LITE
NotifyOnCompactionCompleted(c->column_family_data(), c.get(), status,
compaction_job_stats, job_context->job_id);
}
if (status.ok() || status.IsCompactionTooLarge()) {
// Done
} else if (status.IsShutdownInProgress()) {
// Ignore compaction errors found during shutting down
} else {
ROCKS_LOG_WARN(immutable_db_options_.info_log, "Compaction error: %s",
status.ToString().c_str());
error_handler_.SetBGError(status, BackgroundErrorReason::kCompaction);
if (c != nullptr && !is_manual && !error_handler_.IsBGWorkStopped()) {
// Put this cfd back in the compaction queue so we can retry after some
// time
auto cfd = c->column_family_data();
assert(cfd != nullptr);
// Since this compaction failed, we need to recompute the score so it
// takes the original input files into account
c->column_family_data()
->current()
->storage_info()
->ComputeCompactionScore(*(c->immutable_cf_options()),
*(c->mutable_cf_options()));
if (!cfd->queued_for_compaction()) {
AddToCompactionQueue(cfd);
++unscheduled_compactions_;
}
}
}
// this will unref its input_version and column_family_data
c.reset();
if (is_manual) {
ManualCompactionState* m = manual_compaction;
if (!status.ok()) {
m->status = status;
m->done = true;
}
// For universal compaction:
// Because universal compaction always happens at level 0, so one
// compaction will pick up all overlapped files. No files will be
// filtered out due to size limit and left for a successive compaction.
// So we can safely conclude the current compaction.
//
// Also note that, if we don't stop here, then the current compaction
// writes a new file back to level 0, which will be used in successive
// compaction. Hence the manual compaction will never finish.
//
// Stop the compaction if manual_end points to nullptr -- this means
// that we compacted the whole range. manual_end should always point
// to nullptr in case of universal compaction
if (m->manual_end == nullptr) {
m->done = true;
}
if (!m->done) {
// We only compacted part of the requested range. Update *m
// to the range that is left to be compacted.
// Universal and FIFO compactions should always compact the whole range
assert(m->cfd->ioptions()->compaction_style !=
kCompactionStyleUniversal ||
m->cfd->ioptions()->num_levels > 1);
assert(m->cfd->ioptions()->compaction_style != kCompactionStyleFIFO);
m->tmp_storage = *m->manual_end;
m->begin = &m->tmp_storage;
m->incomplete = true;
}
m->in_progress = false; // not being processed anymore
}
TEST_SYNC_POINT("DBImpl::BackgroundCompaction:Finish");
return status;
}
bool DBImpl::HasPendingManualCompaction() {
return (!manual_compaction_dequeue_.empty());
}
void DBImpl::AddManualCompaction(DBImpl::ManualCompactionState* m) {
manual_compaction_dequeue_.push_back(m);
}
void DBImpl::RemoveManualCompaction(DBImpl::ManualCompactionState* m) {
// Remove from queue
std::deque<ManualCompactionState*>::iterator it =
manual_compaction_dequeue_.begin();
while (it != manual_compaction_dequeue_.end()) {
if (m == (*it)) {
it = manual_compaction_dequeue_.erase(it);
return;
}
it++;
}
assert(false);
return;
}
bool DBImpl::ShouldntRunManualCompaction(ManualCompactionState* m) {
if (num_running_ingest_file_ > 0) {
// We need to wait for other IngestExternalFile() calls to finish
// before running a manual compaction.
return true;
}
if (m->exclusive) {
return (bg_bottom_compaction_scheduled_ > 0 ||
bg_compaction_scheduled_ > 0);
}
std::deque<ManualCompactionState*>::iterator it =
manual_compaction_dequeue_.begin();
bool seen = false;
while (it != manual_compaction_dequeue_.end()) {
if (m == (*it)) {
it++;
seen = true;
continue;
} else if (MCOverlap(m, (*it)) && (!seen && !(*it)->in_progress)) {
// Consider the other manual compaction *it, conflicts if:
// overlaps with m
// and (*it) is ahead in the queue and is not yet in progress
return true;
}
it++;
}
return false;
}
bool DBImpl::HaveManualCompaction(ColumnFamilyData* cfd) {
// Remove from priority queue
std::deque<ManualCompactionState*>::iterator it =
manual_compaction_dequeue_.begin();
while (it != manual_compaction_dequeue_.end()) {
if ((*it)->exclusive) {
return true;
}
if ((cfd == (*it)->cfd) && (!((*it)->in_progress || (*it)->done))) {
// Allow automatic compaction if manual compaction is
// in progress
return true;
}
it++;
}
return false;
}
bool DBImpl::HasExclusiveManualCompaction() {
// Remove from priority queue
std::deque<ManualCompactionState*>::iterator it =
manual_compaction_dequeue_.begin();
while (it != manual_compaction_dequeue_.end()) {
if ((*it)->exclusive) {
return true;
}
it++;
}
return false;
}
bool DBImpl::MCOverlap(ManualCompactionState* m, ManualCompactionState* m1) {
if ((m->exclusive) || (m1->exclusive)) {
return true;
}
if (m->cfd != m1->cfd) {
return false;
}
return true;
}
// SuperVersionContext gets created and destructed outside of the lock --
// we use this conveniently to:
// * malloc one SuperVersion() outside of the lock -- new_superversion
// * delete SuperVersion()s outside of the lock -- superversions_to_free
//
// However, if InstallSuperVersionAndScheduleWork() gets called twice with the
// same sv_context, we can't reuse the SuperVersion() that got
// malloced because
// first call already used it. In that rare case, we take a hit and create a
// new SuperVersion() inside of the mutex. We do similar thing
// for superversion_to_free
void DBImpl::InstallSuperVersionAndScheduleWork(
ColumnFamilyData* cfd, SuperVersionContext* sv_context,
const MutableCFOptions& mutable_cf_options,
FlushReason /* flush_reason */) {
// TODO(yanqin) investigate if 'flush_reason' can be removed since it's not
// used.
mutex_.AssertHeld();
// Update max_total_in_memory_state_
size_t old_memtable_size = 0;
auto* old_sv = cfd->GetSuperVersion();
if (old_sv) {
old_memtable_size = old_sv->mutable_cf_options.write_buffer_size *
old_sv->mutable_cf_options.max_write_buffer_number;
}
// this branch is unlikely to step in
if (UNLIKELY(sv_context->new_superversion == nullptr)) {
sv_context->NewSuperVersion();
}
cfd->InstallSuperVersion(sv_context, &mutex_, mutable_cf_options);
// Whenever we install new SuperVersion, we might need to issue new flushes or
// compactions.
SchedulePendingCompaction(cfd);
MaybeScheduleFlushOrCompaction();
// Update max_total_in_memory_state_
max_total_in_memory_state_ = max_total_in_memory_state_ - old_memtable_size +
mutable_cf_options.write_buffer_size *
mutable_cf_options.max_write_buffer_number;
}
// ShouldPurge is called by FindObsoleteFiles when doing a full scan,
// and db mutex (mutex_) should already be held. This function performs a
// linear scan of an vector (files_grabbed_for_purge_) in search of a
// certain element. We expect FindObsoleteFiles with full scan to occur once
// every 10 hours by default, and the size of the vector is small.
// Therefore, the cost is affordable even if the mutex is held.
// Actually, the current implementation of FindObsoleteFiles with
// full_scan=true can issue I/O requests to obtain list of files in
// directories, e.g. env_->getChildren while holding db mutex.
// In the future, if we want to reduce the cost of search, we may try to keep
// the vector sorted.
bool DBImpl::ShouldPurge(uint64_t file_number) const {
for (auto fn : files_grabbed_for_purge_) {
if (file_number == fn) {
return false;
}
}
for (const auto& purge_file_info : purge_queue_) {
if (purge_file_info.number == file_number) {
return false;
}
}
return true;
}
// MarkAsGrabbedForPurge is called by FindObsoleteFiles, and db mutex
// (mutex_) should already be held.
void DBImpl::MarkAsGrabbedForPurge(uint64_t file_number) {
files_grabbed_for_purge_.emplace_back(file_number);
}
void DBImpl::SetSnapshotChecker(SnapshotChecker* snapshot_checker) {
InstrumentedMutexLock l(&mutex_);
// snapshot_checker_ should only set once. If we need to set it multiple
// times, we need to make sure the old one is not deleted while it is still
// using by a compaction job.
assert(!snapshot_checker_);
snapshot_checker_.reset(snapshot_checker);
}
} // namespace rocksdb
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