rocksdb/db/column_family.cc

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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/column_family.h"
#include <algorithm>
#include <cinttypes>
#include <limits>
#include <sstream>
#include <string>
#include <vector>
#include "db/blob/blob_file_cache.h"
#include "db/compaction/compaction_picker.h"
#include "db/compaction/compaction_picker_fifo.h"
#include "db/compaction/compaction_picker_level.h"
#include "db/compaction/compaction_picker_universal.h"
#include "db/db_impl/db_impl.h"
#include "db/internal_stats.h"
#include "db/job_context.h"
#include "db/range_del_aggregator.h"
#include "db/table_properties_collector.h"
#include "db/version_set.h"
#include "db/write_controller.h"
#include "file/sst_file_manager_impl.h"
#include "memtable/hash_skiplist_rep.h"
#include "monitoring/thread_status_util.h"
#include "options/options_helper.h"
Auto enable Periodic Compactions if a Compaction Filter is used (#5865) Summary: - Periodic compactions are auto-enabled if a compaction filter or a compaction filter factory is set, in Level Compaction. - The default value of `periodic_compaction_seconds` is changed to UINT64_MAX, which lets RocksDB auto-tune periodic compactions as needed. An explicit value of 0 will still work as before ie. to disable periodic compactions completely. For now, on seeing a compaction filter along with a UINT64_MAX value for `periodic_compaction_seconds`, RocksDB will make SST files older than 30 days to go through periodic copmactions. Some RocksDB users make use of compaction filters to control when their data can be deleted, usually with a custom TTL logic. But it is occasionally possible that the compactions get delayed by considerable time due to factors like low writes to a key range, data reaching bottom level, etc before the TTL expiry. Periodic Compactions feature was originally built to help such cases. Now periodic compactions are auto enabled by default when compaction filters or compaction filter factories are used, as it is generally helpful to all cases to collect garbage. `periodic_compaction_seconds` is set to a large value, 30 days, in `SanitizeOptions` when RocksDB sees that a `compaction_filter` or `compaction_filter_factory` is used. This is done only for Level Compaction style. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5865 Test Plan: - Added a new test `DBCompactionTest.LevelPeriodicCompactionWithCompactionFilters` to make sure that `periodic_compaction_seconds` is set if either `compaction_filter` or `compaction_filter_factory` options are set. - `COMPILE_WITH_ASAN=1 make check` Differential Revision: D17659180 Pulled By: sagar0 fbshipit-source-id: 4887b9cf2e53cf2dc93a7b658c6b15e1181217ee
2019-10-29 23:04:26 +01:00
#include "port/port.h"
#include "rocksdb/table.h"
#include "table/merging_iterator.h"
#include "util/autovector.h"
#include "util/cast_util.h"
#include "util/compression.h"
namespace ROCKSDB_NAMESPACE {
ColumnFamilyHandleImpl::ColumnFamilyHandleImpl(
ColumnFamilyData* column_family_data, DBImpl* db, InstrumentedMutex* mutex)
: cfd_(column_family_data), db_(db), mutex_(mutex) {
if (cfd_ != nullptr) {
cfd_->Ref();
}
}
ColumnFamilyHandleImpl::~ColumnFamilyHandleImpl() {
if (cfd_ != nullptr) {
#ifndef ROCKSDB_LITE
for (auto& listener : cfd_->ioptions()->listeners) {
listener->OnColumnFamilyHandleDeletionStarted(this);
}
#endif // ROCKSDB_LITE
// Job id == 0 means that this is not our background process, but rather
// user thread
// Need to hold some shared pointers owned by the initial_cf_options
// before final cleaning up finishes.
ColumnFamilyOptions initial_cf_options_copy = cfd_->initial_cf_options();
JobContext job_context(0);
mutex_->Lock();
bool dropped = cfd_->IsDropped();
if (cfd_->UnrefAndTryDelete()) {
if (dropped) {
db_->FindObsoleteFiles(&job_context, false, true);
}
}
mutex_->Unlock();
if (job_context.HaveSomethingToDelete()) {
bool defer_purge =
db_->immutable_db_options().avoid_unnecessary_blocking_io;
db_->PurgeObsoleteFiles(job_context, defer_purge);
if (defer_purge) {
mutex_->Lock();
db_->SchedulePurge();
mutex_->Unlock();
}
}
job_context.Clean();
}
}
uint32_t ColumnFamilyHandleImpl::GetID() const { return cfd()->GetID(); }
const std::string& ColumnFamilyHandleImpl::GetName() const {
return cfd()->GetName();
}
Status ColumnFamilyHandleImpl::GetDescriptor(ColumnFamilyDescriptor* desc) {
#ifndef ROCKSDB_LITE
// accessing mutable cf-options requires db mutex.
InstrumentedMutexLock l(mutex_);
*desc = ColumnFamilyDescriptor(cfd()->GetName(), cfd()->GetLatestCFOptions());
return Status::OK();
#else
(void)desc;
return Status::NotSupported();
#endif // !ROCKSDB_LITE
}
const Comparator* ColumnFamilyHandleImpl::GetComparator() const {
return cfd()->user_comparator();
}
void GetIntTblPropCollectorFactory(
const ImmutableCFOptions& ioptions,
std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
int_tbl_prop_collector_factories) {
auto& collector_factories = ioptions.table_properties_collector_factories;
for (size_t i = 0; i < ioptions.table_properties_collector_factories.size();
++i) {
assert(collector_factories[i]);
int_tbl_prop_collector_factories->emplace_back(
new UserKeyTablePropertiesCollectorFactory(collector_factories[i]));
}
}
Status CheckCompressionSupported(const ColumnFamilyOptions& cf_options) {
if (!cf_options.compression_per_level.empty()) {
for (size_t level = 0; level < cf_options.compression_per_level.size();
++level) {
if (!CompressionTypeSupported(cf_options.compression_per_level[level])) {
return Status::InvalidArgument(
"Compression type " +
CompressionTypeToString(cf_options.compression_per_level[level]) +
" is not linked with the binary.");
}
}
} else {
if (!CompressionTypeSupported(cf_options.compression)) {
return Status::InvalidArgument(
"Compression type " +
CompressionTypeToString(cf_options.compression) +
" is not linked with the binary.");
}
}
if (cf_options.compression_opts.zstd_max_train_bytes > 0) {
if (!ZSTD_TrainDictionarySupported()) {
return Status::InvalidArgument(
"zstd dictionary trainer cannot be used because ZSTD 1.1.3+ "
"is not linked with the binary.");
}
if (cf_options.compression_opts.max_dict_bytes == 0) {
return Status::InvalidArgument(
"The dictionary size limit (`CompressionOptions::max_dict_bytes`) "
"should be nonzero if we're using zstd's dictionary generator.");
}
}
if (!CompressionTypeSupported(cf_options.blob_compression_type)) {
std::ostringstream oss;
oss << "The specified blob compression type "
<< CompressionTypeToString(cf_options.blob_compression_type)
<< " is not available.";
return Status::InvalidArgument(oss.str());
}
return Status::OK();
}
support for concurrent adds to memtable Summary: This diff adds support for concurrent adds to the skiplist memtable implementations. Memory allocation is made thread-safe by the addition of a spinlock, with small per-core buffers to avoid contention. Concurrent memtable writes are made via an additional method and don't impose a performance overhead on the non-concurrent case, so parallelism can be selected on a per-batch basis. Write thread synchronization is an increasing bottleneck for higher levels of concurrency, so this diff adds --enable_write_thread_adaptive_yield (default off). This feature causes threads joining a write batch group to spin for a short time (default 100 usec) using sched_yield, rather than going to sleep on a mutex. If the timing of the yield calls indicates that another thread has actually run during the yield then spinning is avoided. This option improves performance for concurrent situations even without parallel adds, although it has the potential to increase CPU usage (and the heuristic adaptation is not yet mature). Parallel writes are not currently compatible with inplace updates, update callbacks, or delete filtering. Enable it with --allow_concurrent_memtable_write (and --enable_write_thread_adaptive_yield). Parallel memtable writes are performance neutral when there is no actual parallelism, and in my experiments (SSD server-class Linux and varying contention and key sizes for fillrandom) they are always a performance win when there is more than one thread. Statistics are updated earlier in the write path, dropping the number of DB mutex acquisitions from 2 to 1 for almost all cases. This diff was motivated and inspired by Yahoo's cLSM work. It is more conservative than cLSM: RocksDB's write batch group leader role is preserved (along with all of the existing flush and write throttling logic) and concurrent writers are blocked until all memtable insertions have completed and the sequence number has been advanced, to preserve linearizability. My test config is "db_bench -benchmarks=fillrandom -threads=$T -batch_size=1 -memtablerep=skip_list -value_size=100 --num=1000000/$T -level0_slowdown_writes_trigger=9999 -level0_stop_writes_trigger=9999 -disable_auto_compactions --max_write_buffer_number=8 -max_background_flushes=8 --disable_wal --write_buffer_size=160000000 --block_size=16384 --allow_concurrent_memtable_write" on a two-socket Xeon E5-2660 @ 2.2Ghz with lots of memory and an SSD hard drive. With 1 thread I get ~440Kops/sec. Peak performance for 1 socket (numactl -N1) is slightly more than 1Mops/sec, at 16 threads. Peak performance across both sockets happens at 30 threads, and is ~900Kops/sec, although with fewer threads there is less performance loss when the system has background work. Test Plan: 1. concurrent stress tests for InlineSkipList and DynamicBloom 2. make clean; make check 3. make clean; DISABLE_JEMALLOC=1 make valgrind_check; valgrind db_bench 4. make clean; COMPILE_WITH_TSAN=1 make all check; db_bench 5. make clean; COMPILE_WITH_ASAN=1 make all check; db_bench 6. make clean; OPT=-DROCKSDB_LITE make check 7. verify no perf regressions when disabled Reviewers: igor, sdong Reviewed By: sdong Subscribers: MarkCallaghan, IslamAbdelRahman, anthony, yhchiang, rven, sdong, guyg8, kradhakrishnan, dhruba Differential Revision: https://reviews.facebook.net/D50589
2015-08-15 01:59:07 +02:00
Status CheckConcurrentWritesSupported(const ColumnFamilyOptions& cf_options) {
if (cf_options.inplace_update_support) {
return Status::InvalidArgument(
"In-place memtable updates (inplace_update_support) is not compatible "
"with concurrent writes (allow_concurrent_memtable_write)");
}
if (!cf_options.memtable_factory->IsInsertConcurrentlySupported()) {
return Status::InvalidArgument(
"Memtable doesn't concurrent writes (allow_concurrent_memtable_write)");
}
support for concurrent adds to memtable Summary: This diff adds support for concurrent adds to the skiplist memtable implementations. Memory allocation is made thread-safe by the addition of a spinlock, with small per-core buffers to avoid contention. Concurrent memtable writes are made via an additional method and don't impose a performance overhead on the non-concurrent case, so parallelism can be selected on a per-batch basis. Write thread synchronization is an increasing bottleneck for higher levels of concurrency, so this diff adds --enable_write_thread_adaptive_yield (default off). This feature causes threads joining a write batch group to spin for a short time (default 100 usec) using sched_yield, rather than going to sleep on a mutex. If the timing of the yield calls indicates that another thread has actually run during the yield then spinning is avoided. This option improves performance for concurrent situations even without parallel adds, although it has the potential to increase CPU usage (and the heuristic adaptation is not yet mature). Parallel writes are not currently compatible with inplace updates, update callbacks, or delete filtering. Enable it with --allow_concurrent_memtable_write (and --enable_write_thread_adaptive_yield). Parallel memtable writes are performance neutral when there is no actual parallelism, and in my experiments (SSD server-class Linux and varying contention and key sizes for fillrandom) they are always a performance win when there is more than one thread. Statistics are updated earlier in the write path, dropping the number of DB mutex acquisitions from 2 to 1 for almost all cases. This diff was motivated and inspired by Yahoo's cLSM work. It is more conservative than cLSM: RocksDB's write batch group leader role is preserved (along with all of the existing flush and write throttling logic) and concurrent writers are blocked until all memtable insertions have completed and the sequence number has been advanced, to preserve linearizability. My test config is "db_bench -benchmarks=fillrandom -threads=$T -batch_size=1 -memtablerep=skip_list -value_size=100 --num=1000000/$T -level0_slowdown_writes_trigger=9999 -level0_stop_writes_trigger=9999 -disable_auto_compactions --max_write_buffer_number=8 -max_background_flushes=8 --disable_wal --write_buffer_size=160000000 --block_size=16384 --allow_concurrent_memtable_write" on a two-socket Xeon E5-2660 @ 2.2Ghz with lots of memory and an SSD hard drive. With 1 thread I get ~440Kops/sec. Peak performance for 1 socket (numactl -N1) is slightly more than 1Mops/sec, at 16 threads. Peak performance across both sockets happens at 30 threads, and is ~900Kops/sec, although with fewer threads there is less performance loss when the system has background work. Test Plan: 1. concurrent stress tests for InlineSkipList and DynamicBloom 2. make clean; make check 3. make clean; DISABLE_JEMALLOC=1 make valgrind_check; valgrind db_bench 4. make clean; COMPILE_WITH_TSAN=1 make all check; db_bench 5. make clean; COMPILE_WITH_ASAN=1 make all check; db_bench 6. make clean; OPT=-DROCKSDB_LITE make check 7. verify no perf regressions when disabled Reviewers: igor, sdong Reviewed By: sdong Subscribers: MarkCallaghan, IslamAbdelRahman, anthony, yhchiang, rven, sdong, guyg8, kradhakrishnan, dhruba Differential Revision: https://reviews.facebook.net/D50589
2015-08-15 01:59:07 +02:00
return Status::OK();
}
Status CheckCFPathsSupported(const DBOptions& db_options,
const ColumnFamilyOptions& cf_options) {
// More than one cf_paths are supported only in universal
// and level compaction styles. This function also checks the case
// in which cf_paths is not specified, which results in db_paths
// being used.
if ((cf_options.compaction_style != kCompactionStyleUniversal) &&
(cf_options.compaction_style != kCompactionStyleLevel)) {
if (cf_options.cf_paths.size() > 1) {
return Status::NotSupported(
"More than one CF paths are only supported in "
"universal and level compaction styles. ");
} else if (cf_options.cf_paths.empty() &&
db_options.db_paths.size() > 1) {
return Status::NotSupported(
"More than one DB paths are only supported in "
"universal and level compaction styles. ");
}
}
return Status::OK();
}
namespace {
const uint64_t kDefaultTtl = 0xfffffffffffffffe;
const uint64_t kDefaultPeriodicCompSecs = 0xfffffffffffffffe;
}; // namespace
ColumnFamilyOptions SanitizeOptions(const ImmutableDBOptions& db_options,
const ColumnFamilyOptions& src) {
ColumnFamilyOptions result = src;
size_t clamp_max = std::conditional<
sizeof(size_t) == 4, std::integral_constant<size_t, 0xffffffff>,
std::integral_constant<uint64_t, 64ull << 30>>::type::value;
ClipToRange(&result.write_buffer_size, ((size_t)64) << 10, clamp_max);
// if user sets arena_block_size, we trust user to use this value. Otherwise,
// calculate a proper value from writer_buffer_size;
if (result.arena_block_size <= 0) {
result.arena_block_size = result.write_buffer_size / 8;
// Align up to 4k
const size_t align = 4 * 1024;
result.arena_block_size =
((result.arena_block_size + align - 1) / align) * align;
}
result.min_write_buffer_number_to_merge =
std::min(result.min_write_buffer_number_to_merge,
result.max_write_buffer_number - 1);
if (result.min_write_buffer_number_to_merge < 1) {
result.min_write_buffer_number_to_merge = 1;
}
if (result.num_levels < 1) {
result.num_levels = 1;
}
if (result.compaction_style == kCompactionStyleLevel &&
result.num_levels < 2) {
result.num_levels = 2;
}
if (result.compaction_style == kCompactionStyleUniversal &&
db_options.allow_ingest_behind && result.num_levels < 3) {
result.num_levels = 3;
}
if (result.max_write_buffer_number < 2) {
result.max_write_buffer_number = 2;
}
Refactor trimming logic for immutable memtables (#5022) Summary: MyRocks currently sets `max_write_buffer_number_to_maintain` in order to maintain enough history for transaction conflict checking. The effectiveness of this approach depends on the size of memtables. When memtables are small, it may not keep enough history; when memtables are large, this may consume too much memory. We are proposing a new way to configure memtable list history: by limiting the memory usage of immutable memtables. The new option is `max_write_buffer_size_to_maintain` and it will take precedence over the old `max_write_buffer_number_to_maintain` if they are both set to non-zero values. The new option accounts for the total memory usage of flushed immutable memtables and mutable memtable. When the total usage exceeds the limit, RocksDB may start dropping immutable memtables (which is also called trimming history), starting from the oldest one. The semantics of the old option actually works both as an upper bound and lower bound. History trimming will start if number of immutable memtables exceeds the limit, but it will never go below (limit-1) due to history trimming. In order the mimic the behavior with the new option, history trimming will stop if dropping the next immutable memtable causes the total memory usage go below the size limit. For example, assuming the size limit is set to 64MB, and there are 3 immutable memtables with sizes of 20, 30, 30. Although the total memory usage is 80MB > 64MB, dropping the oldest memtable will reduce the memory usage to 60MB < 64MB, so in this case no memtable will be dropped. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5022 Differential Revision: D14394062 Pulled By: miasantreble fbshipit-source-id: 60457a509c6af89d0993f988c9b5c2aa9e45f5c5
2019-08-23 22:54:09 +02:00
// fall back max_write_buffer_number_to_maintain if
// max_write_buffer_size_to_maintain is not set
if (result.max_write_buffer_size_to_maintain < 0) {
result.max_write_buffer_size_to_maintain =
result.max_write_buffer_number *
static_cast<int64_t>(result.write_buffer_size);
} else if (result.max_write_buffer_size_to_maintain == 0 &&
result.max_write_buffer_number_to_maintain < 0) {
Support saving history in memtable_list Summary: For transactions, we are using the memtables to validate that there are no write conflicts. But after flushing, we don't have any memtables, and transactions could fail to commit. So we want to someone keep around some extra history to use for conflict checking. In addition, we want to provide a way to increase the size of this history if too many transactions fail to commit. After chatting with people, it seems like everyone prefers just using Memtables to store this history (instead of a separate history structure). It seems like the best place for this is abstracted inside the memtable_list. I decide to create a separate list in MemtableListVersion as using the same list complicated the flush/installalflushresults logic too much. This diff adds a new parameter to control how much memtable history to keep around after flushing. However, it sounds like people aren't too fond of adding new parameters. So I am making the default size of flushed+not-flushed memtables be set to max_write_buffers. This should not change the maximum amount of memory used, but make it more likely we're using closer the the limit. (We are now postponing deleting flushed memtables until the max_write_buffer limit is reached). So while we might use more memory on average, we are still obeying the limit set (and you could argue it's better to go ahead and use up memory now instead of waiting for a write stall to happen to test this limit). However, if people are opposed to this default behavior, we can easily set it to 0 and require this parameter be set in order to use transactions. Test Plan: Added a xfunc test to play around with setting different values of this parameter in all tests. Added testing in memtablelist_test and planning on adding more testing here. Reviewers: sdong, rven, igor Reviewed By: igor Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D37443
2015-05-29 01:34:24 +02:00
result.max_write_buffer_number_to_maintain = result.max_write_buffer_number;
}
// bloom filter size shouldn't exceed 1/4 of memtable size.
if (result.memtable_prefix_bloom_size_ratio > 0.25) {
result.memtable_prefix_bloom_size_ratio = 0.25;
} else if (result.memtable_prefix_bloom_size_ratio < 0) {
result.memtable_prefix_bloom_size_ratio = 0;
}
Support saving history in memtable_list Summary: For transactions, we are using the memtables to validate that there are no write conflicts. But after flushing, we don't have any memtables, and transactions could fail to commit. So we want to someone keep around some extra history to use for conflict checking. In addition, we want to provide a way to increase the size of this history if too many transactions fail to commit. After chatting with people, it seems like everyone prefers just using Memtables to store this history (instead of a separate history structure). It seems like the best place for this is abstracted inside the memtable_list. I decide to create a separate list in MemtableListVersion as using the same list complicated the flush/installalflushresults logic too much. This diff adds a new parameter to control how much memtable history to keep around after flushing. However, it sounds like people aren't too fond of adding new parameters. So I am making the default size of flushed+not-flushed memtables be set to max_write_buffers. This should not change the maximum amount of memory used, but make it more likely we're using closer the the limit. (We are now postponing deleting flushed memtables until the max_write_buffer limit is reached). So while we might use more memory on average, we are still obeying the limit set (and you could argue it's better to go ahead and use up memory now instead of waiting for a write stall to happen to test this limit). However, if people are opposed to this default behavior, we can easily set it to 0 and require this parameter be set in order to use transactions. Test Plan: Added a xfunc test to play around with setting different values of this parameter in all tests. Added testing in memtablelist_test and planning on adding more testing here. Reviewers: sdong, rven, igor Reviewed By: igor Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D37443
2015-05-29 01:34:24 +02:00
if (!result.prefix_extractor) {
assert(result.memtable_factory);
Slice name = result.memtable_factory->Name();
if (name.compare("HashSkipListRepFactory") == 0 ||
name.compare("HashLinkListRepFactory") == 0) {
result.memtable_factory = std::make_shared<SkipListFactory>();
}
}
if (result.compaction_style == kCompactionStyleFIFO) {
result.num_levels = 1;
// since we delete level0 files in FIFO compaction when there are too many
// of them, these options don't really mean anything
result.level0_slowdown_writes_trigger = std::numeric_limits<int>::max();
result.level0_stop_writes_trigger = std::numeric_limits<int>::max();
}
if (result.max_bytes_for_level_multiplier <= 0) {
result.max_bytes_for_level_multiplier = 1;
}
if (result.level0_file_num_compaction_trigger == 0) {
ROCKS_LOG_WARN(db_options.info_log.get(),
"level0_file_num_compaction_trigger cannot be 0");
result.level0_file_num_compaction_trigger = 1;
}
if (result.level0_stop_writes_trigger <
result.level0_slowdown_writes_trigger ||
result.level0_slowdown_writes_trigger <
result.level0_file_num_compaction_trigger) {
ROCKS_LOG_WARN(db_options.info_log.get(),
"This condition must be satisfied: "
"level0_stop_writes_trigger(%d) >= "
"level0_slowdown_writes_trigger(%d) >= "
"level0_file_num_compaction_trigger(%d)",
result.level0_stop_writes_trigger,
result.level0_slowdown_writes_trigger,
result.level0_file_num_compaction_trigger);
if (result.level0_slowdown_writes_trigger <
result.level0_file_num_compaction_trigger) {
result.level0_slowdown_writes_trigger =
result.level0_file_num_compaction_trigger;
}
if (result.level0_stop_writes_trigger <
result.level0_slowdown_writes_trigger) {
result.level0_stop_writes_trigger = result.level0_slowdown_writes_trigger;
}
ROCKS_LOG_WARN(db_options.info_log.get(),
"Adjust the value to "
"level0_stop_writes_trigger(%d)"
"level0_slowdown_writes_trigger(%d)"
"level0_file_num_compaction_trigger(%d)",
result.level0_stop_writes_trigger,
result.level0_slowdown_writes_trigger,
result.level0_file_num_compaction_trigger);
}
if (result.soft_pending_compaction_bytes_limit == 0) {
result.soft_pending_compaction_bytes_limit =
result.hard_pending_compaction_bytes_limit;
} else if (result.hard_pending_compaction_bytes_limit > 0 &&
result.soft_pending_compaction_bytes_limit >
result.hard_pending_compaction_bytes_limit) {
result.soft_pending_compaction_bytes_limit =
result.hard_pending_compaction_bytes_limit;
}
#ifndef ROCKSDB_LITE
// When the DB is stopped, it's possible that there are some .trash files that
// were not deleted yet, when we open the DB we will find these .trash files
// and schedule them to be deleted (or delete immediately if SstFileManager
// was not used)
auto sfm = static_cast<SstFileManagerImpl*>(db_options.sst_file_manager.get());
for (size_t i = 0; i < result.cf_paths.size(); i++) {
DeleteScheduler::CleanupDirectory(db_options.env, sfm,
result.cf_paths[i].path)
.PermitUncheckedError();
}
#endif
if (result.cf_paths.empty()) {
result.cf_paths = db_options.db_paths;
}
if (result.level_compaction_dynamic_level_bytes) {
if (result.compaction_style != kCompactionStyleLevel ||
result.cf_paths.size() > 1U) {
// 1. level_compaction_dynamic_level_bytes only makes sense for
// level-based compaction.
// 2. we don't yet know how to make both of this feature and multiple
// DB path work.
result.level_compaction_dynamic_level_bytes = false;
}
}
if (result.max_compaction_bytes == 0) {
result.max_compaction_bytes = result.target_file_size_base * 25;
}
bool is_block_based_table = (result.table_factory->IsInstanceOf(
TableFactory::kBlockBasedTableName()));
const uint64_t kAdjustedTtl = 30 * 24 * 60 * 60;
if (result.ttl == kDefaultTtl) {
if (is_block_based_table &&
result.compaction_style != kCompactionStyleFIFO) {
result.ttl = kAdjustedTtl;
} else {
result.ttl = 0;
}
}
const uint64_t kAdjustedPeriodicCompSecs = 30 * 24 * 60 * 60;
Auto enable Periodic Compactions if a Compaction Filter is used (#5865) Summary: - Periodic compactions are auto-enabled if a compaction filter or a compaction filter factory is set, in Level Compaction. - The default value of `periodic_compaction_seconds` is changed to UINT64_MAX, which lets RocksDB auto-tune periodic compactions as needed. An explicit value of 0 will still work as before ie. to disable periodic compactions completely. For now, on seeing a compaction filter along with a UINT64_MAX value for `periodic_compaction_seconds`, RocksDB will make SST files older than 30 days to go through periodic copmactions. Some RocksDB users make use of compaction filters to control when their data can be deleted, usually with a custom TTL logic. But it is occasionally possible that the compactions get delayed by considerable time due to factors like low writes to a key range, data reaching bottom level, etc before the TTL expiry. Periodic Compactions feature was originally built to help such cases. Now periodic compactions are auto enabled by default when compaction filters or compaction filter factories are used, as it is generally helpful to all cases to collect garbage. `periodic_compaction_seconds` is set to a large value, 30 days, in `SanitizeOptions` when RocksDB sees that a `compaction_filter` or `compaction_filter_factory` is used. This is done only for Level Compaction style. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5865 Test Plan: - Added a new test `DBCompactionTest.LevelPeriodicCompactionWithCompactionFilters` to make sure that `periodic_compaction_seconds` is set if either `compaction_filter` or `compaction_filter_factory` options are set. - `COMPILE_WITH_ASAN=1 make check` Differential Revision: D17659180 Pulled By: sagar0 fbshipit-source-id: 4887b9cf2e53cf2dc93a7b658c6b15e1181217ee
2019-10-29 23:04:26 +01:00
// Turn on periodic compactions and set them to occur once every 30 days if
// compaction filters are used and periodic_compaction_seconds is set to the
// default value.
if (result.compaction_style != kCompactionStyleFIFO) {
if ((result.compaction_filter != nullptr ||
result.compaction_filter_factory != nullptr) &&
result.periodic_compaction_seconds == kDefaultPeriodicCompSecs &&
is_block_based_table) {
result.periodic_compaction_seconds = kAdjustedPeriodicCompSecs;
}
} else {
// result.compaction_style == kCompactionStyleFIFO
if (result.ttl == 0) {
if (is_block_based_table) {
if (result.periodic_compaction_seconds == kDefaultPeriodicCompSecs) {
result.periodic_compaction_seconds = kAdjustedPeriodicCompSecs;
}
result.ttl = result.periodic_compaction_seconds;
}
} else if (result.periodic_compaction_seconds != 0) {
result.ttl = std::min(result.ttl, result.periodic_compaction_seconds);
}
Auto enable Periodic Compactions if a Compaction Filter is used (#5865) Summary: - Periodic compactions are auto-enabled if a compaction filter or a compaction filter factory is set, in Level Compaction. - The default value of `periodic_compaction_seconds` is changed to UINT64_MAX, which lets RocksDB auto-tune periodic compactions as needed. An explicit value of 0 will still work as before ie. to disable periodic compactions completely. For now, on seeing a compaction filter along with a UINT64_MAX value for `periodic_compaction_seconds`, RocksDB will make SST files older than 30 days to go through periodic copmactions. Some RocksDB users make use of compaction filters to control when their data can be deleted, usually with a custom TTL logic. But it is occasionally possible that the compactions get delayed by considerable time due to factors like low writes to a key range, data reaching bottom level, etc before the TTL expiry. Periodic Compactions feature was originally built to help such cases. Now periodic compactions are auto enabled by default when compaction filters or compaction filter factories are used, as it is generally helpful to all cases to collect garbage. `periodic_compaction_seconds` is set to a large value, 30 days, in `SanitizeOptions` when RocksDB sees that a `compaction_filter` or `compaction_filter_factory` is used. This is done only for Level Compaction style. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5865 Test Plan: - Added a new test `DBCompactionTest.LevelPeriodicCompactionWithCompactionFilters` to make sure that `periodic_compaction_seconds` is set if either `compaction_filter` or `compaction_filter_factory` options are set. - `COMPILE_WITH_ASAN=1 make check` Differential Revision: D17659180 Pulled By: sagar0 fbshipit-source-id: 4887b9cf2e53cf2dc93a7b658c6b15e1181217ee
2019-10-29 23:04:26 +01:00
}
// TTL compactions would work similar to Periodic Compactions in Universal in
// most of the cases. So, if ttl is set, execute the periodic compaction
// codepath.
if (result.compaction_style == kCompactionStyleUniversal && result.ttl != 0) {
if (result.periodic_compaction_seconds != 0) {
result.periodic_compaction_seconds =
std::min(result.ttl, result.periodic_compaction_seconds);
} else {
result.periodic_compaction_seconds = result.ttl;
}
}
if (result.periodic_compaction_seconds == kDefaultPeriodicCompSecs) {
result.periodic_compaction_seconds = 0;
}
return result;
}
int SuperVersion::dummy = 0;
void* const SuperVersion::kSVInUse = &SuperVersion::dummy;
void* const SuperVersion::kSVObsolete = nullptr;
SuperVersion::~SuperVersion() {
for (auto td : to_delete) {
delete td;
}
}
SuperVersion* SuperVersion::Ref() {
refs.fetch_add(1, std::memory_order_relaxed);
return this;
}
bool SuperVersion::Unref() {
// fetch_sub returns the previous value of ref
uint32_t previous_refs = refs.fetch_sub(1);
assert(previous_refs > 0);
return previous_refs == 1;
}
void SuperVersion::Cleanup() {
assert(refs.load(std::memory_order_relaxed) == 0);
imm->Unref(&to_delete);
MemTable* m = mem->Unref();
if (m != nullptr) {
auto* memory_usage = current->cfd()->imm()->current_memory_usage();
assert(*memory_usage >= m->ApproximateMemoryUsage());
*memory_usage -= m->ApproximateMemoryUsage();
to_delete.push_back(m);
}
current->Unref();
cfd->UnrefAndTryDelete(this);
}
void SuperVersion::Init(ColumnFamilyData* new_cfd, MemTable* new_mem,
MemTableListVersion* new_imm, Version* new_current) {
cfd = new_cfd;
mem = new_mem;
imm = new_imm;
current = new_current;
cfd->Ref();
mem->Ref();
imm->Ref();
current->Ref();
refs.store(1, std::memory_order_relaxed);
}
namespace {
void SuperVersionUnrefHandle(void* ptr) {
// UnrefHandle is called when a thread exists or a ThreadLocalPtr gets
// destroyed. When former happens, the thread shouldn't see kSVInUse.
// When latter happens, we are in ~ColumnFamilyData(), no get should happen as
// well.
SuperVersion* sv = static_cast<SuperVersion*>(ptr);
bool was_last_ref __attribute__((__unused__));
was_last_ref = sv->Unref();
// Thread-local SuperVersions can't outlive ColumnFamilyData::super_version_.
// This is important because we can't do SuperVersion cleanup here.
// That would require locking DB mutex, which would deadlock because
// SuperVersionUnrefHandle is called with locked ThreadLocalPtr mutex.
assert(!was_last_ref);
}
} // anonymous namespace
std::vector<std::string> ColumnFamilyData::GetDbPaths() const {
std::vector<std::string> paths;
paths.reserve(ioptions_.cf_paths.size());
for (const DbPath& db_path : ioptions_.cf_paths) {
paths.emplace_back(db_path.path);
}
return paths;
}
const uint32_t ColumnFamilyData::kDummyColumnFamilyDataId = port::kMaxUint32;
Rewritten system for scheduling background work Summary: When scaling to higher number of column families, the worst bottleneck was MaybeScheduleFlushOrCompaction(), which did a for loop over all column families while holding a mutex. This patch addresses the issue. The approach is similar to our earlier efforts: instead of a pull-model, where we do something for every column family, we can do a push-based model -- when we detect that column family is ready to be flushed/compacted, we add it to the flush_queue_/compaction_queue_. That way we don't need to loop over every column family in MaybeScheduleFlushOrCompaction. Here are the performance results: Command: ./db_bench --write_buffer_size=268435456 --db_write_buffer_size=268435456 --db=/fast-rocksdb-tmp/rocks_lots_of_cf --use_existing_db=0 --open_files=55000 --statistics=1 --histogram=1 --disable_data_sync=1 --max_write_buffer_number=2 --sync=0 --benchmarks=fillrandom --threads=16 --num_column_families=5000 --disable_wal=1 --max_background_flushes=16 --max_background_compactions=16 --level0_file_num_compaction_trigger=2 --level0_slowdown_writes_trigger=2 --level0_stop_writes_trigger=3 --hard_rate_limit=1 --num=33333333 --writes=33333333 Before the patch: fillrandom : 26.950 micros/op 37105 ops/sec; 4.1 MB/s After the patch: fillrandom : 17.404 micros/op 57456 ops/sec; 6.4 MB/s Next bottleneck is VersionSet::AddLiveFiles, which is painfully slow when we have a lot of files. This is coming in the next patch, but when I removed that code, here's what I got: fillrandom : 7.590 micros/op 131758 ops/sec; 14.6 MB/s Test Plan: make check two stress tests: Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 max_background_flushes=0, to verify that this case also works correctly ./db_stress --threads=30 --ops_per_thread=2000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=3 --max_background_compactions=3 --max_background_flushes=0 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: ljin, rven, yhchiang, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30123
2014-12-19 20:38:12 +01:00
ColumnFamilyData::ColumnFamilyData(
uint32_t id, const std::string& name, Version* _dummy_versions,
Cache* _table_cache, WriteBufferManager* write_buffer_manager,
const ColumnFamilyOptions& cf_options, const ImmutableDBOptions& db_options,
Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
2019-12-13 23:47:08 +01:00
const FileOptions& file_options, ColumnFamilySet* column_family_set,
BlockCacheTracer* const block_cache_tracer,
const std::shared_ptr<IOTracer>& io_tracer)
: id_(id),
name_(name),
dummy_versions_(_dummy_versions),
current_(nullptr),
refs_(0),
initialized_(false),
dropped_(false),
internal_comparator_(cf_options.comparator),
initial_cf_options_(SanitizeOptions(db_options, cf_options)),
ioptions_(db_options, initial_cf_options_),
mutable_cf_options_(initial_cf_options_),
is_delete_range_supported_(
cf_options.table_factory->IsDeleteRangeSupported()),
write_buffer_manager_(write_buffer_manager),
mem_(nullptr),
imm_(ioptions_.min_write_buffer_number_to_merge,
Refactor trimming logic for immutable memtables (#5022) Summary: MyRocks currently sets `max_write_buffer_number_to_maintain` in order to maintain enough history for transaction conflict checking. The effectiveness of this approach depends on the size of memtables. When memtables are small, it may not keep enough history; when memtables are large, this may consume too much memory. We are proposing a new way to configure memtable list history: by limiting the memory usage of immutable memtables. The new option is `max_write_buffer_size_to_maintain` and it will take precedence over the old `max_write_buffer_number_to_maintain` if they are both set to non-zero values. The new option accounts for the total memory usage of flushed immutable memtables and mutable memtable. When the total usage exceeds the limit, RocksDB may start dropping immutable memtables (which is also called trimming history), starting from the oldest one. The semantics of the old option actually works both as an upper bound and lower bound. History trimming will start if number of immutable memtables exceeds the limit, but it will never go below (limit-1) due to history trimming. In order the mimic the behavior with the new option, history trimming will stop if dropping the next immutable memtable causes the total memory usage go below the size limit. For example, assuming the size limit is set to 64MB, and there are 3 immutable memtables with sizes of 20, 30, 30. Although the total memory usage is 80MB > 64MB, dropping the oldest memtable will reduce the memory usage to 60MB < 64MB, so in this case no memtable will be dropped. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5022 Differential Revision: D14394062 Pulled By: miasantreble fbshipit-source-id: 60457a509c6af89d0993f988c9b5c2aa9e45f5c5
2019-08-23 22:54:09 +02:00
ioptions_.max_write_buffer_number_to_maintain,
ioptions_.max_write_buffer_size_to_maintain),
super_version_(nullptr),
super_version_number_(0),
local_sv_(new ThreadLocalPtr(&SuperVersionUnrefHandle)),
next_(nullptr),
prev_(nullptr),
log_number_(0),
FlushReason improvement Summary: Right now flush reason "SuperVersion Change" covers a few different scenarios which is a bit vague. For example, the following db_bench job should trigger "Write Buffer Full" > $ TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -write_buffer_size=1048576 -target_file_size_base=1048576 -max_bytes_for_level_base=4194304 $ grep 'flush_reason' /dev/shm/dbbench/LOG ... 2018/03/06-17:30:42.543638 7f2773b99700 EVENT_LOG_v1 {"time_micros": 1520386242543634, "job": 192, "event": "flush_started", "num_memtables": 1, "num_entries": 7006, "num_deletes": 0, "memory_usage": 1018024, "flush_reason": "SuperVersion Change"} 2018/03/06-17:30:42.569541 7f2773b99700 EVENT_LOG_v1 {"time_micros": 1520386242569536, "job": 193, "event": "flush_started", "num_memtables": 1, "num_entries": 7006, "num_deletes": 0, "memory_usage": 1018104, "flush_reason": "SuperVersion Change"} 2018/03/06-17:30:42.596396 7f2773b99700 EVENT_LOG_v1 {"time_micros": 1520386242596392, "job": 194, "event": "flush_started", "num_memtables": 1, "num_entries": 7008, "num_deletes": 0, "memory_usage": 1018048, "flush_reason": "SuperVersion Change"} 2018/03/06-17:30:42.622444 7f2773b99700 EVENT_LOG_v1 {"time_micros": 1520386242622440, "job": 195, "event": "flush_started", "num_memtables": 1, "num_entries": 7006, "num_deletes": 0, "memory_usage": 1018104, "flush_reason": "SuperVersion Change"} With the fix: > 2018/03/19-14:40:02.341451 7f11dc257700 EVENT_LOG_v1 {"time_micros": 1521495602341444, "job": 98, "event": "flush_started", "num_memtables": 1, "num_entries": 7009, "num_deletes": 0, "memory_usage": 1018008, "flush_reason": "Write Buffer Full"} 2018/03/19-14:40:02.379655 7f11dc257700 EVENT_LOG_v1 {"time_micros": 1521495602379642, "job": 100, "event": "flush_started", "num_memtables": 1, "num_entries": 7006, "num_deletes": 0, "memory_usage": 1018016, "flush_reason": "Write Buffer Full"} 2018/03/19-14:40:02.418479 7f11dc257700 EVENT_LOG_v1 {"time_micros": 1521495602418474, "job": 101, "event": "flush_started", "num_memtables": 1, "num_entries": 7009, "num_deletes": 0, "memory_usage": 1018104, "flush_reason": "Write Buffer Full"} 2018/03/19-14:40:02.455084 7f11dc257700 EVENT_LOG_v1 {"time_micros": 1521495602455079, "job": 102, "event": "flush_started", "num_memtables": 1, "num_entries": 7009, "num_deletes": 0, "memory_usage": 1018048, "flush_reason": "Write Buffer Full"} 2018/03/19-14:40:02.492293 7f11dc257700 EVENT_LOG_v1 {"time_micros": 1521495602492288, "job": 104, "event": "flush_started", "num_memtables": 1, "num_entries": 7007, "num_deletes": 0, "memory_usage": 1018056, "flush_reason": "Write Buffer Full"} 2018/03/19-14:40:02.528720 7f11dc257700 EVENT_LOG_v1 {"time_micros": 1521495602528715, "job": 105, "event": "flush_started", "num_memtables": 1, "num_entries": 7006, "num_deletes": 0, "memory_usage": 1018104, "flush_reason": "Write Buffer Full"} 2018/03/19-14:40:02.566255 7f11dc257700 EVENT_LOG_v1 {"time_micros": 1521495602566238, "job": 107, "event": "flush_started", "num_memtables": 1, "num_entries": 7009, "num_deletes": 0, "memory_usage": 1018112, "flush_reason": "Write Buffer Full"} Closes https://github.com/facebook/rocksdb/pull/3627 Differential Revision: D7328772 Pulled By: miasantreble fbshipit-source-id: 67c94065fbdd36930f09930aad0aaa6d2c152bb8
2018-03-23 02:34:04 +01:00
flush_reason_(FlushReason::kOthers),
Rewritten system for scheduling background work Summary: When scaling to higher number of column families, the worst bottleneck was MaybeScheduleFlushOrCompaction(), which did a for loop over all column families while holding a mutex. This patch addresses the issue. The approach is similar to our earlier efforts: instead of a pull-model, where we do something for every column family, we can do a push-based model -- when we detect that column family is ready to be flushed/compacted, we add it to the flush_queue_/compaction_queue_. That way we don't need to loop over every column family in MaybeScheduleFlushOrCompaction. Here are the performance results: Command: ./db_bench --write_buffer_size=268435456 --db_write_buffer_size=268435456 --db=/fast-rocksdb-tmp/rocks_lots_of_cf --use_existing_db=0 --open_files=55000 --statistics=1 --histogram=1 --disable_data_sync=1 --max_write_buffer_number=2 --sync=0 --benchmarks=fillrandom --threads=16 --num_column_families=5000 --disable_wal=1 --max_background_flushes=16 --max_background_compactions=16 --level0_file_num_compaction_trigger=2 --level0_slowdown_writes_trigger=2 --level0_stop_writes_trigger=3 --hard_rate_limit=1 --num=33333333 --writes=33333333 Before the patch: fillrandom : 26.950 micros/op 37105 ops/sec; 4.1 MB/s After the patch: fillrandom : 17.404 micros/op 57456 ops/sec; 6.4 MB/s Next bottleneck is VersionSet::AddLiveFiles, which is painfully slow when we have a lot of files. This is coming in the next patch, but when I removed that code, here's what I got: fillrandom : 7.590 micros/op 131758 ops/sec; 14.6 MB/s Test Plan: make check two stress tests: Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 max_background_flushes=0, to verify that this case also works correctly ./db_stress --threads=30 --ops_per_thread=2000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=3 --max_background_compactions=3 --max_background_flushes=0 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: ljin, rven, yhchiang, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30123
2014-12-19 20:38:12 +01:00
column_family_set_(column_family_set),
queued_for_flush_(false),
queued_for_compaction_(false),
prev_compaction_needed_bytes_(0),
allow_2pc_(db_options.allow_2pc),
last_memtable_id_(0),
db_paths_registered_(false) {
if (id_ != kDummyColumnFamilyDataId) {
// TODO(cc): RegisterDbPaths can be expensive, considering moving it
// outside of this constructor which might be called with db mutex held.
// TODO(cc): considering using ioptions_.fs, currently some tests rely on
// EnvWrapper, that's the main reason why we use env here.
Status s = ioptions_.env->RegisterDbPaths(GetDbPaths());
if (s.ok()) {
db_paths_registered_ = true;
} else {
ROCKS_LOG_ERROR(
ioptions_.info_log,
"Failed to register data paths of column family (id: %d, name: %s)",
id_, name_.c_str());
}
}
Ref();
// Convert user defined table properties collector factories to internal ones.
GetIntTblPropCollectorFactory(ioptions_, &int_tbl_prop_collector_factories_);
// if _dummy_versions is nullptr, then this is a dummy column family.
if (_dummy_versions != nullptr) {
make internal stats independent of statistics Summary: also make it aware of column family output from db_bench ``` ** Compaction Stats [default] ** Level Files Size(MB) Score Read(GB) Rn(GB) Rnp1(GB) Write(GB) Wnew(GB) RW-Amp W-Amp Rd(MB/s) Wr(MB/s) Rn(cnt) Rnp1(cnt) Wnp1(cnt) Wnew(cnt) Comp(sec) Comp(cnt) Avg(sec) Stall(sec) Stall(cnt) Avg(ms) ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ L0 14 956 0.9 0.0 0.0 0.0 2.7 2.7 0.0 0.0 0.0 111.6 0 0 0 0 24 40 0.612 75.20 492387 0.15 L1 21 2001 2.0 5.7 2.0 3.7 5.3 1.6 5.4 2.6 71.2 65.7 31 43 55 12 82 2 41.242 43.72 41183 1.06 L2 217 18974 1.9 16.5 2.0 14.4 15.1 0.7 15.6 7.4 70.1 64.3 17 182 185 3 241 16 15.052 0.00 0 0.00 L3 1641 188245 1.8 9.1 1.1 8.0 8.5 0.5 15.4 7.4 61.3 57.2 9 75 76 1 152 9 16.887 0.00 0 0.00 L4 4447 449025 0.4 13.4 4.8 8.6 9.1 0.5 4.7 1.9 77.8 52.7 38 79 100 21 176 38 4.639 0.00 0 0.00 Sum 6340 659201 0.0 44.7 10.0 34.7 40.6 6.0 32.0 15.2 67.7 61.6 95 379 416 37 676 105 6.439 118.91 533570 0.22 Int 0 0 0.0 1.2 0.4 0.8 1.3 0.5 5.2 2.7 59.1 65.6 3 7 9 2 20 10 2.003 0.00 0 0.00 Stalls(secs): 75.197 level0_slowdown, 0.000 level0_numfiles, 0.000 memtable_compaction, 43.717 leveln_slowdown Stalls(count): 492387 level0_slowdown, 0 level0_numfiles, 0 memtable_compaction, 41183 leveln_slowdown ** DB Stats ** Uptime(secs): 202.1 total, 13.5 interval Cumulative writes: 6291456 writes, 6291456 batches, 1.0 writes per batch, 4.90 ingest GB Cumulative WAL: 6291456 writes, 6291456 syncs, 1.00 writes per sync, 4.90 GB written Interval writes: 1048576 writes, 1048576 batches, 1.0 writes per batch, 836.0 ingest MB Interval WAL: 1048576 writes, 1048576 syncs, 1.00 writes per sync, 0.82 MB written Test Plan: ran it Reviewers: sdong, yhchiang, igor Reviewed By: igor Subscribers: leveldb Differential Revision: https://reviews.facebook.net/D19917
2014-07-21 21:57:29 +02:00
internal_stats_.reset(
new InternalStats(ioptions_.num_levels, db_options.env, this));
Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
2019-12-13 23:47:08 +01:00
table_cache_.reset(new TableCache(ioptions_, file_options, _table_cache,
block_cache_tracer, io_tracer));
blob_file_cache_.reset(
new BlobFileCache(_table_cache, ioptions(), soptions(), id_,
internal_stats_->GetBlobFileReadHist()));
if (ioptions_.compaction_style == kCompactionStyleLevel) {
compaction_picker_.reset(
new LevelCompactionPicker(ioptions_, &internal_comparator_));
#ifndef ROCKSDB_LITE
} else if (ioptions_.compaction_style == kCompactionStyleUniversal) {
compaction_picker_.reset(
new UniversalCompactionPicker(ioptions_, &internal_comparator_));
} else if (ioptions_.compaction_style == kCompactionStyleFIFO) {
compaction_picker_.reset(
new FIFOCompactionPicker(ioptions_, &internal_comparator_));
} else if (ioptions_.compaction_style == kCompactionStyleNone) {
compaction_picker_.reset(new NullCompactionPicker(
ioptions_, &internal_comparator_));
ROCKS_LOG_WARN(ioptions_.info_log,
"Column family %s does not use any background compaction. "
"Compactions can only be done via CompactFiles\n",
GetName().c_str());
#endif // !ROCKSDB_LITE
} else {
ROCKS_LOG_ERROR(ioptions_.info_log,
"Unable to recognize the specified compaction style %d. "
"Column family %s will use kCompactionStyleLevel.\n",
ioptions_.compaction_style, GetName().c_str());
compaction_picker_.reset(
new LevelCompactionPicker(ioptions_, &internal_comparator_));
}
Rewritten system for scheduling background work Summary: When scaling to higher number of column families, the worst bottleneck was MaybeScheduleFlushOrCompaction(), which did a for loop over all column families while holding a mutex. This patch addresses the issue. The approach is similar to our earlier efforts: instead of a pull-model, where we do something for every column family, we can do a push-based model -- when we detect that column family is ready to be flushed/compacted, we add it to the flush_queue_/compaction_queue_. That way we don't need to loop over every column family in MaybeScheduleFlushOrCompaction. Here are the performance results: Command: ./db_bench --write_buffer_size=268435456 --db_write_buffer_size=268435456 --db=/fast-rocksdb-tmp/rocks_lots_of_cf --use_existing_db=0 --open_files=55000 --statistics=1 --histogram=1 --disable_data_sync=1 --max_write_buffer_number=2 --sync=0 --benchmarks=fillrandom --threads=16 --num_column_families=5000 --disable_wal=1 --max_background_flushes=16 --max_background_compactions=16 --level0_file_num_compaction_trigger=2 --level0_slowdown_writes_trigger=2 --level0_stop_writes_trigger=3 --hard_rate_limit=1 --num=33333333 --writes=33333333 Before the patch: fillrandom : 26.950 micros/op 37105 ops/sec; 4.1 MB/s After the patch: fillrandom : 17.404 micros/op 57456 ops/sec; 6.4 MB/s Next bottleneck is VersionSet::AddLiveFiles, which is painfully slow when we have a lot of files. This is coming in the next patch, but when I removed that code, here's what I got: fillrandom : 7.590 micros/op 131758 ops/sec; 14.6 MB/s Test Plan: make check two stress tests: Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 max_background_flushes=0, to verify that this case also works correctly ./db_stress --threads=30 --ops_per_thread=2000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=3 --max_background_compactions=3 --max_background_flushes=0 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: ljin, rven, yhchiang, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30123
2014-12-19 20:38:12 +01:00
if (column_family_set_->NumberOfColumnFamilies() < 10) {
ROCKS_LOG_INFO(ioptions_.info_log,
"--------------- Options for column family [%s]:\n",
name.c_str());
initial_cf_options_.Dump(ioptions_.info_log);
Rewritten system for scheduling background work Summary: When scaling to higher number of column families, the worst bottleneck was MaybeScheduleFlushOrCompaction(), which did a for loop over all column families while holding a mutex. This patch addresses the issue. The approach is similar to our earlier efforts: instead of a pull-model, where we do something for every column family, we can do a push-based model -- when we detect that column family is ready to be flushed/compacted, we add it to the flush_queue_/compaction_queue_. That way we don't need to loop over every column family in MaybeScheduleFlushOrCompaction. Here are the performance results: Command: ./db_bench --write_buffer_size=268435456 --db_write_buffer_size=268435456 --db=/fast-rocksdb-tmp/rocks_lots_of_cf --use_existing_db=0 --open_files=55000 --statistics=1 --histogram=1 --disable_data_sync=1 --max_write_buffer_number=2 --sync=0 --benchmarks=fillrandom --threads=16 --num_column_families=5000 --disable_wal=1 --max_background_flushes=16 --max_background_compactions=16 --level0_file_num_compaction_trigger=2 --level0_slowdown_writes_trigger=2 --level0_stop_writes_trigger=3 --hard_rate_limit=1 --num=33333333 --writes=33333333 Before the patch: fillrandom : 26.950 micros/op 37105 ops/sec; 4.1 MB/s After the patch: fillrandom : 17.404 micros/op 57456 ops/sec; 6.4 MB/s Next bottleneck is VersionSet::AddLiveFiles, which is painfully slow when we have a lot of files. This is coming in the next patch, but when I removed that code, here's what I got: fillrandom : 7.590 micros/op 131758 ops/sec; 14.6 MB/s Test Plan: make check two stress tests: Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 max_background_flushes=0, to verify that this case also works correctly ./db_stress --threads=30 --ops_per_thread=2000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=3 --max_background_compactions=3 --max_background_flushes=0 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: ljin, rven, yhchiang, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30123
2014-12-19 20:38:12 +01:00
} else {
ROCKS_LOG_INFO(ioptions_.info_log, "\t(skipping printing options)\n");
Rewritten system for scheduling background work Summary: When scaling to higher number of column families, the worst bottleneck was MaybeScheduleFlushOrCompaction(), which did a for loop over all column families while holding a mutex. This patch addresses the issue. The approach is similar to our earlier efforts: instead of a pull-model, where we do something for every column family, we can do a push-based model -- when we detect that column family is ready to be flushed/compacted, we add it to the flush_queue_/compaction_queue_. That way we don't need to loop over every column family in MaybeScheduleFlushOrCompaction. Here are the performance results: Command: ./db_bench --write_buffer_size=268435456 --db_write_buffer_size=268435456 --db=/fast-rocksdb-tmp/rocks_lots_of_cf --use_existing_db=0 --open_files=55000 --statistics=1 --histogram=1 --disable_data_sync=1 --max_write_buffer_number=2 --sync=0 --benchmarks=fillrandom --threads=16 --num_column_families=5000 --disable_wal=1 --max_background_flushes=16 --max_background_compactions=16 --level0_file_num_compaction_trigger=2 --level0_slowdown_writes_trigger=2 --level0_stop_writes_trigger=3 --hard_rate_limit=1 --num=33333333 --writes=33333333 Before the patch: fillrandom : 26.950 micros/op 37105 ops/sec; 4.1 MB/s After the patch: fillrandom : 17.404 micros/op 57456 ops/sec; 6.4 MB/s Next bottleneck is VersionSet::AddLiveFiles, which is painfully slow when we have a lot of files. This is coming in the next patch, but when I removed that code, here's what I got: fillrandom : 7.590 micros/op 131758 ops/sec; 14.6 MB/s Test Plan: make check two stress tests: Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 max_background_flushes=0, to verify that this case also works correctly ./db_stress --threads=30 --ops_per_thread=2000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=3 --max_background_compactions=3 --max_background_flushes=0 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: ljin, rven, yhchiang, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30123
2014-12-19 20:38:12 +01:00
}
}
RecalculateWriteStallConditions(mutable_cf_options_);
}
// DB mutex held
ColumnFamilyData::~ColumnFamilyData() {
assert(refs_.load(std::memory_order_relaxed) == 0);
// remove from linked list
auto prev = prev_;
auto next = next_;
prev->next_ = next;
next->prev_ = prev;
2015-01-06 21:44:21 +01:00
if (!dropped_ && column_family_set_ != nullptr) {
// If it's dropped, it's already removed from column family set
// If column_family_set_ == nullptr, this is dummy CFD and not in
// ColumnFamilySet
column_family_set_->RemoveColumnFamily(this);
}
if (current_ != nullptr) {
current_->Unref();
}
Rewritten system for scheduling background work Summary: When scaling to higher number of column families, the worst bottleneck was MaybeScheduleFlushOrCompaction(), which did a for loop over all column families while holding a mutex. This patch addresses the issue. The approach is similar to our earlier efforts: instead of a pull-model, where we do something for every column family, we can do a push-based model -- when we detect that column family is ready to be flushed/compacted, we add it to the flush_queue_/compaction_queue_. That way we don't need to loop over every column family in MaybeScheduleFlushOrCompaction. Here are the performance results: Command: ./db_bench --write_buffer_size=268435456 --db_write_buffer_size=268435456 --db=/fast-rocksdb-tmp/rocks_lots_of_cf --use_existing_db=0 --open_files=55000 --statistics=1 --histogram=1 --disable_data_sync=1 --max_write_buffer_number=2 --sync=0 --benchmarks=fillrandom --threads=16 --num_column_families=5000 --disable_wal=1 --max_background_flushes=16 --max_background_compactions=16 --level0_file_num_compaction_trigger=2 --level0_slowdown_writes_trigger=2 --level0_stop_writes_trigger=3 --hard_rate_limit=1 --num=33333333 --writes=33333333 Before the patch: fillrandom : 26.950 micros/op 37105 ops/sec; 4.1 MB/s After the patch: fillrandom : 17.404 micros/op 57456 ops/sec; 6.4 MB/s Next bottleneck is VersionSet::AddLiveFiles, which is painfully slow when we have a lot of files. This is coming in the next patch, but when I removed that code, here's what I got: fillrandom : 7.590 micros/op 131758 ops/sec; 14.6 MB/s Test Plan: make check two stress tests: Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 max_background_flushes=0, to verify that this case also works correctly ./db_stress --threads=30 --ops_per_thread=2000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=3 --max_background_compactions=3 --max_background_flushes=0 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: ljin, rven, yhchiang, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30123
2014-12-19 20:38:12 +01:00
// It would be wrong if this ColumnFamilyData is in flush_queue_ or
// compaction_queue_ and we destroyed it
assert(!queued_for_flush_);
assert(!queued_for_compaction_);
assert(super_version_ == nullptr);
if (dummy_versions_ != nullptr) {
// List must be empty
assert(dummy_versions_->TEST_Next() == dummy_versions_);
bool deleted __attribute__((__unused__));
deleted = dummy_versions_->Unref();
assert(deleted);
}
if (mem_ != nullptr) {
delete mem_->Unref();
}
autovector<MemTable*> to_delete;
imm_.current()->Unref(&to_delete);
for (MemTable* m : to_delete) {
delete m;
}
if (db_paths_registered_) {
// TODO(cc): considering using ioptions_.fs, currently some tests rely on
// EnvWrapper, that's the main reason why we use env here.
Status s = ioptions_.env->UnregisterDbPaths(GetDbPaths());
if (!s.ok()) {
ROCKS_LOG_ERROR(
ioptions_.info_log,
"Failed to unregister data paths of column family (id: %d, name: %s)",
id_, name_.c_str());
}
}
}
bool ColumnFamilyData::UnrefAndTryDelete(SuperVersion* sv_under_cleanup) {
int old_refs = refs_.fetch_sub(1);
assert(old_refs > 0);
if (old_refs == 1) {
assert(super_version_ == nullptr);
delete this;
return true;
}
// If called under SuperVersion::Cleanup, we should not re-enter Cleanup on
// the same SuperVersion. (But while installing a new SuperVersion, this
// cfd could be referenced only by two SuperVersions.)
if (old_refs == 2 && super_version_ != nullptr &&
super_version_ != sv_under_cleanup) {
// Only the super_version_ holds me
SuperVersion* sv = super_version_;
super_version_ = nullptr;
// Release SuperVersion reference kept in ThreadLocalPtr.
// This must be done outside of mutex_ since unref handler can lock mutex.
sv->db_mutex->Unlock();
local_sv_.reset();
sv->db_mutex->Lock();
if (sv->Unref()) {
// May delete this ColumnFamilyData after calling Cleanup()
sv->Cleanup();
delete sv;
return true;
}
}
return false;
}
2015-01-06 21:44:21 +01:00
void ColumnFamilyData::SetDropped() {
// can't drop default CF
assert(id_ != 0);
dropped_ = true;
write_controller_token_.reset();
// remove from column_family_set
column_family_set_->RemoveColumnFamily(this);
}
ColumnFamilyOptions ColumnFamilyData::GetLatestCFOptions() const {
return BuildColumnFamilyOptions(initial_cf_options_, mutable_cf_options_);
}
uint64_t ColumnFamilyData::OldestLogToKeep() {
auto current_log = GetLogNumber();
if (allow_2pc_) {
auto imm_prep_log = imm()->PrecomputeMinLogContainingPrepSection();
auto mem_prep_log = mem()->GetMinLogContainingPrepSection();
if (imm_prep_log > 0 && imm_prep_log < current_log) {
current_log = imm_prep_log;
}
if (mem_prep_log > 0 && mem_prep_log < current_log) {
current_log = mem_prep_log;
}
}
return current_log;
}
const double kIncSlowdownRatio = 0.8;
const double kDecSlowdownRatio = 1 / kIncSlowdownRatio;
const double kNearStopSlowdownRatio = 0.6;
const double kDelayRecoverSlowdownRatio = 1.4;
namespace {
// If penalize_stop is true, we further reduce slowdown rate.
std::unique_ptr<WriteControllerToken> SetupDelay(
WriteController* write_controller, uint64_t compaction_needed_bytes,
uint64_t prev_compaction_need_bytes, bool penalize_stop,
bool auto_comapctions_disabled) {
const uint64_t kMinWriteRate = 16 * 1024u; // Minimum write rate 16KB/s.
uint64_t max_write_rate = write_controller->max_delayed_write_rate();
uint64_t write_rate = write_controller->delayed_write_rate();
if (auto_comapctions_disabled) {
// When auto compaction is disabled, always use the value user gave.
write_rate = max_write_rate;
} else if (write_controller->NeedsDelay() && max_write_rate > kMinWriteRate) {
// If user gives rate less than kMinWriteRate, don't adjust it.
//
// If already delayed, need to adjust based on previous compaction debt.
// When there are two or more column families require delay, we always
// increase or reduce write rate based on information for one single
// column family. It is likely to be OK but we can improve if there is a
// problem.
// Ignore compaction_needed_bytes = 0 case because compaction_needed_bytes
// is only available in level-based compaction
//
// If the compaction debt stays the same as previously, we also further slow
// down. It usually means a mem table is full. It's mainly for the case
// where both of flush and compaction are much slower than the speed we
// insert to mem tables, so we need to actively slow down before we get
// feedback signal from compaction and flushes to avoid the full stop
// because of hitting the max write buffer number.
//
// If DB just falled into the stop condition, we need to further reduce
// the write rate to avoid the stop condition.
if (penalize_stop) {
// Penalize the near stop or stop condition by more aggressive slowdown.
// This is to provide the long term slowdown increase signal.
// The penalty is more than the reward of recovering to the normal
// condition.
write_rate = static_cast<uint64_t>(static_cast<double>(write_rate) *
kNearStopSlowdownRatio);
if (write_rate < kMinWriteRate) {
write_rate = kMinWriteRate;
}
} else if (prev_compaction_need_bytes > 0 &&
prev_compaction_need_bytes <= compaction_needed_bytes) {
write_rate = static_cast<uint64_t>(static_cast<double>(write_rate) *
kIncSlowdownRatio);
if (write_rate < kMinWriteRate) {
write_rate = kMinWriteRate;
}
} else if (prev_compaction_need_bytes > compaction_needed_bytes) {
// We are speeding up by ratio of kSlowdownRatio when we have paid
// compaction debt. But we'll never speed up to faster than the write rate
// given by users.
write_rate = static_cast<uint64_t>(static_cast<double>(write_rate) *
kDecSlowdownRatio);
if (write_rate > max_write_rate) {
write_rate = max_write_rate;
}
}
}
return write_controller->GetDelayToken(write_rate);
}
int GetL0ThresholdSpeedupCompaction(int level0_file_num_compaction_trigger,
int level0_slowdown_writes_trigger) {
// SanitizeOptions() ensures it.
assert(level0_file_num_compaction_trigger <= level0_slowdown_writes_trigger);
if (level0_file_num_compaction_trigger < 0) {
return std::numeric_limits<int>::max();
}
const int64_t twice_level0_trigger =
static_cast<int64_t>(level0_file_num_compaction_trigger) * 2;
const int64_t one_fourth_trigger_slowdown =
static_cast<int64_t>(level0_file_num_compaction_trigger) +
((level0_slowdown_writes_trigger - level0_file_num_compaction_trigger) /
4);
assert(twice_level0_trigger >= 0);
assert(one_fourth_trigger_slowdown >= 0);
// 1/4 of the way between L0 compaction trigger threshold and slowdown
// condition.
// Or twice as compaction trigger, if it is smaller.
int64_t res = std::min(twice_level0_trigger, one_fourth_trigger_slowdown);
if (res >= port::kMaxInt32) {
return port::kMaxInt32;
} else {
// res fits in int
return static_cast<int>(res);
}
}
} // namespace
std::pair<WriteStallCondition, ColumnFamilyData::WriteStallCause>
ColumnFamilyData::GetWriteStallConditionAndCause(
int num_unflushed_memtables, int num_l0_files,
uint64_t num_compaction_needed_bytes,
const MutableCFOptions& mutable_cf_options) {
if (num_unflushed_memtables >= mutable_cf_options.max_write_buffer_number) {
return {WriteStallCondition::kStopped, WriteStallCause::kMemtableLimit};
} else if (!mutable_cf_options.disable_auto_compactions &&
num_l0_files >= mutable_cf_options.level0_stop_writes_trigger) {
return {WriteStallCondition::kStopped, WriteStallCause::kL0FileCountLimit};
} else if (!mutable_cf_options.disable_auto_compactions &&
mutable_cf_options.hard_pending_compaction_bytes_limit > 0 &&
num_compaction_needed_bytes >=
mutable_cf_options.hard_pending_compaction_bytes_limit) {
return {WriteStallCondition::kStopped,
WriteStallCause::kPendingCompactionBytes};
} else if (mutable_cf_options.max_write_buffer_number > 3 &&
num_unflushed_memtables >=
mutable_cf_options.max_write_buffer_number - 1) {
return {WriteStallCondition::kDelayed, WriteStallCause::kMemtableLimit};
} else if (!mutable_cf_options.disable_auto_compactions &&
mutable_cf_options.level0_slowdown_writes_trigger >= 0 &&
num_l0_files >=
mutable_cf_options.level0_slowdown_writes_trigger) {
return {WriteStallCondition::kDelayed, WriteStallCause::kL0FileCountLimit};
} else if (!mutable_cf_options.disable_auto_compactions &&
mutable_cf_options.soft_pending_compaction_bytes_limit > 0 &&
num_compaction_needed_bytes >=
mutable_cf_options.soft_pending_compaction_bytes_limit) {
return {WriteStallCondition::kDelayed,
WriteStallCause::kPendingCompactionBytes};
}
return {WriteStallCondition::kNormal, WriteStallCause::kNone};
}
WriteStallCondition ColumnFamilyData::RecalculateWriteStallConditions(
const MutableCFOptions& mutable_cf_options) {
auto write_stall_condition = WriteStallCondition::kNormal;
if (current_ != nullptr) {
auto* vstorage = current_->storage_info();
auto write_controller = column_family_set_->write_controller_;
uint64_t compaction_needed_bytes =
vstorage->estimated_compaction_needed_bytes();
auto write_stall_condition_and_cause = GetWriteStallConditionAndCause(
imm()->NumNotFlushed(), vstorage->l0_delay_trigger_count(),
vstorage->estimated_compaction_needed_bytes(), mutable_cf_options);
write_stall_condition = write_stall_condition_and_cause.first;
auto write_stall_cause = write_stall_condition_and_cause.second;
bool was_stopped = write_controller->IsStopped();
bool needed_delay = write_controller->NeedsDelay();
if (write_stall_condition == WriteStallCondition::kStopped &&
write_stall_cause == WriteStallCause::kMemtableLimit) {
write_controller_token_ = write_controller->GetStopToken();
internal_stats_->AddCFStats(InternalStats::MEMTABLE_LIMIT_STOPS, 1);
ROCKS_LOG_WARN(
ioptions_.info_log,
"[%s] Stopping writes because we have %d immutable memtables "
"(waiting for flush), max_write_buffer_number is set to %d",
Support saving history in memtable_list Summary: For transactions, we are using the memtables to validate that there are no write conflicts. But after flushing, we don't have any memtables, and transactions could fail to commit. So we want to someone keep around some extra history to use for conflict checking. In addition, we want to provide a way to increase the size of this history if too many transactions fail to commit. After chatting with people, it seems like everyone prefers just using Memtables to store this history (instead of a separate history structure). It seems like the best place for this is abstracted inside the memtable_list. I decide to create a separate list in MemtableListVersion as using the same list complicated the flush/installalflushresults logic too much. This diff adds a new parameter to control how much memtable history to keep around after flushing. However, it sounds like people aren't too fond of adding new parameters. So I am making the default size of flushed+not-flushed memtables be set to max_write_buffers. This should not change the maximum amount of memory used, but make it more likely we're using closer the the limit. (We are now postponing deleting flushed memtables until the max_write_buffer limit is reached). So while we might use more memory on average, we are still obeying the limit set (and you could argue it's better to go ahead and use up memory now instead of waiting for a write stall to happen to test this limit). However, if people are opposed to this default behavior, we can easily set it to 0 and require this parameter be set in order to use transactions. Test Plan: Added a xfunc test to play around with setting different values of this parameter in all tests. Added testing in memtablelist_test and planning on adding more testing here. Reviewers: sdong, rven, igor Reviewed By: igor Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D37443
2015-05-29 01:34:24 +02:00
name_.c_str(), imm()->NumNotFlushed(),
mutable_cf_options.max_write_buffer_number);
} else if (write_stall_condition == WriteStallCondition::kStopped &&
write_stall_cause == WriteStallCause::kL0FileCountLimit) {
write_controller_token_ = write_controller->GetStopToken();
internal_stats_->AddCFStats(InternalStats::L0_FILE_COUNT_LIMIT_STOPS, 1);
if (compaction_picker_->IsLevel0CompactionInProgress()) {
internal_stats_->AddCFStats(
InternalStats::LOCKED_L0_FILE_COUNT_LIMIT_STOPS, 1);
}
ROCKS_LOG_WARN(ioptions_.info_log,
"[%s] Stopping writes because we have %d level-0 files",
name_.c_str(), vstorage->l0_delay_trigger_count());
} else if (write_stall_condition == WriteStallCondition::kStopped &&
write_stall_cause == WriteStallCause::kPendingCompactionBytes) {
write_controller_token_ = write_controller->GetStopToken();
internal_stats_->AddCFStats(
InternalStats::PENDING_COMPACTION_BYTES_LIMIT_STOPS, 1);
ROCKS_LOG_WARN(
ioptions_.info_log,
"[%s] Stopping writes because of estimated pending compaction "
"bytes %" PRIu64,
name_.c_str(), compaction_needed_bytes);
} else if (write_stall_condition == WriteStallCondition::kDelayed &&
write_stall_cause == WriteStallCause::kMemtableLimit) {
write_controller_token_ =
SetupDelay(write_controller, compaction_needed_bytes,
prev_compaction_needed_bytes_, was_stopped,
mutable_cf_options.disable_auto_compactions);
internal_stats_->AddCFStats(InternalStats::MEMTABLE_LIMIT_SLOWDOWNS, 1);
ROCKS_LOG_WARN(
ioptions_.info_log,
"[%s] Stalling writes because we have %d immutable memtables "
"(waiting for flush), max_write_buffer_number is set to %d "
"rate %" PRIu64,
name_.c_str(), imm()->NumNotFlushed(),
mutable_cf_options.max_write_buffer_number,
write_controller->delayed_write_rate());
} else if (write_stall_condition == WriteStallCondition::kDelayed &&
write_stall_cause == WriteStallCause::kL0FileCountLimit) {
// L0 is the last two files from stopping.
bool near_stop = vstorage->l0_delay_trigger_count() >=
mutable_cf_options.level0_stop_writes_trigger - 2;
write_controller_token_ =
SetupDelay(write_controller, compaction_needed_bytes,
prev_compaction_needed_bytes_, was_stopped || near_stop,
mutable_cf_options.disable_auto_compactions);
internal_stats_->AddCFStats(InternalStats::L0_FILE_COUNT_LIMIT_SLOWDOWNS,
1);
if (compaction_picker_->IsLevel0CompactionInProgress()) {
internal_stats_->AddCFStats(
InternalStats::LOCKED_L0_FILE_COUNT_LIMIT_SLOWDOWNS, 1);
}
ROCKS_LOG_WARN(ioptions_.info_log,
"[%s] Stalling writes because we have %d level-0 files "
"rate %" PRIu64,
name_.c_str(), vstorage->l0_delay_trigger_count(),
write_controller->delayed_write_rate());
} else if (write_stall_condition == WriteStallCondition::kDelayed &&
write_stall_cause == WriteStallCause::kPendingCompactionBytes) {
// If the distance to hard limit is less than 1/4 of the gap between soft
// and
// hard bytes limit, we think it is near stop and speed up the slowdown.
bool near_stop =
mutable_cf_options.hard_pending_compaction_bytes_limit > 0 &&
(compaction_needed_bytes -
mutable_cf_options.soft_pending_compaction_bytes_limit) >
3 * (mutable_cf_options.hard_pending_compaction_bytes_limit -
mutable_cf_options.soft_pending_compaction_bytes_limit) /
4;
write_controller_token_ =
SetupDelay(write_controller, compaction_needed_bytes,
prev_compaction_needed_bytes_, was_stopped || near_stop,
mutable_cf_options.disable_auto_compactions);
internal_stats_->AddCFStats(
InternalStats::PENDING_COMPACTION_BYTES_LIMIT_SLOWDOWNS, 1);
ROCKS_LOG_WARN(
ioptions_.info_log,
"[%s] Stalling writes because of estimated pending compaction "
"bytes %" PRIu64 " rate %" PRIu64,
name_.c_str(), vstorage->estimated_compaction_needed_bytes(),
write_controller->delayed_write_rate());
} else {
assert(write_stall_condition == WriteStallCondition::kNormal);
if (vstorage->l0_delay_trigger_count() >=
GetL0ThresholdSpeedupCompaction(
mutable_cf_options.level0_file_num_compaction_trigger,
mutable_cf_options.level0_slowdown_writes_trigger)) {
write_controller_token_ =
write_controller->GetCompactionPressureToken();
ROCKS_LOG_INFO(
ioptions_.info_log,
"[%s] Increasing compaction threads because we have %d level-0 "
"files ",
name_.c_str(), vstorage->l0_delay_trigger_count());
} else if (vstorage->estimated_compaction_needed_bytes() >=
mutable_cf_options.soft_pending_compaction_bytes_limit / 4) {
// Increase compaction threads if bytes needed for compaction exceeds
// 1/4 of threshold for slowing down.
// If soft pending compaction byte limit is not set, always speed up
// compaction.
write_controller_token_ =
write_controller->GetCompactionPressureToken();
if (mutable_cf_options.soft_pending_compaction_bytes_limit > 0) {
ROCKS_LOG_INFO(
ioptions_.info_log,
"[%s] Increasing compaction threads because of estimated pending "
"compaction "
"bytes %" PRIu64,
name_.c_str(), vstorage->estimated_compaction_needed_bytes());
}
} else {
write_controller_token_.reset();
}
// If the DB recovers from delay conditions, we reward with reducing
// double the slowdown ratio. This is to balance the long term slowdown
// increase signal.
if (needed_delay) {
uint64_t write_rate = write_controller->delayed_write_rate();
write_controller->set_delayed_write_rate(static_cast<uint64_t>(
static_cast<double>(write_rate) * kDelayRecoverSlowdownRatio));
// Set the low pri limit to be 1/4 the delayed write rate.
// Note we don't reset this value even after delay condition is relased.
// Low-pri rate will continue to apply if there is a compaction
// pressure.
write_controller->low_pri_rate_limiter()->SetBytesPerSecond(write_rate /
4);
}
}
prev_compaction_needed_bytes_ = compaction_needed_bytes;
}
return write_stall_condition;
}
Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
2019-12-13 23:47:08 +01:00
const FileOptions* ColumnFamilyData::soptions() const {
return &(column_family_set_->file_options_);
}
void ColumnFamilyData::SetCurrent(Version* current_version) {
current_ = current_version;
}
uint64_t ColumnFamilyData::GetNumLiveVersions() const {
return VersionSet::GetNumLiveVersions(dummy_versions_);
}
uint64_t ColumnFamilyData::GetTotalSstFilesSize() const {
return VersionSet::GetTotalSstFilesSize(dummy_versions_);
}
uint64_t ColumnFamilyData::GetLiveSstFilesSize() const {
return current_->GetSstFilesSize();
}
MemTable* ColumnFamilyData::ConstructNewMemtable(
const MutableCFOptions& mutable_cf_options, SequenceNumber earliest_seq) {
return new MemTable(internal_comparator_, ioptions_, mutable_cf_options,
write_buffer_manager_, earliest_seq, id_);
}
void ColumnFamilyData::CreateNewMemtable(
const MutableCFOptions& mutable_cf_options, SequenceNumber earliest_seq) {
if (mem_ != nullptr) {
delete mem_->Unref();
}
SetMemtable(ConstructNewMemtable(mutable_cf_options, earliest_seq));
mem_->Ref();
}
Rewritten system for scheduling background work Summary: When scaling to higher number of column families, the worst bottleneck was MaybeScheduleFlushOrCompaction(), which did a for loop over all column families while holding a mutex. This patch addresses the issue. The approach is similar to our earlier efforts: instead of a pull-model, where we do something for every column family, we can do a push-based model -- when we detect that column family is ready to be flushed/compacted, we add it to the flush_queue_/compaction_queue_. That way we don't need to loop over every column family in MaybeScheduleFlushOrCompaction. Here are the performance results: Command: ./db_bench --write_buffer_size=268435456 --db_write_buffer_size=268435456 --db=/fast-rocksdb-tmp/rocks_lots_of_cf --use_existing_db=0 --open_files=55000 --statistics=1 --histogram=1 --disable_data_sync=1 --max_write_buffer_number=2 --sync=0 --benchmarks=fillrandom --threads=16 --num_column_families=5000 --disable_wal=1 --max_background_flushes=16 --max_background_compactions=16 --level0_file_num_compaction_trigger=2 --level0_slowdown_writes_trigger=2 --level0_stop_writes_trigger=3 --hard_rate_limit=1 --num=33333333 --writes=33333333 Before the patch: fillrandom : 26.950 micros/op 37105 ops/sec; 4.1 MB/s After the patch: fillrandom : 17.404 micros/op 57456 ops/sec; 6.4 MB/s Next bottleneck is VersionSet::AddLiveFiles, which is painfully slow when we have a lot of files. This is coming in the next patch, but when I removed that code, here's what I got: fillrandom : 7.590 micros/op 131758 ops/sec; 14.6 MB/s Test Plan: make check two stress tests: Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 max_background_flushes=0, to verify that this case also works correctly ./db_stress --threads=30 --ops_per_thread=2000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=3 --max_background_compactions=3 --max_background_flushes=0 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: ljin, rven, yhchiang, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30123
2014-12-19 20:38:12 +01:00
bool ColumnFamilyData::NeedsCompaction() const {
return !mutable_cf_options_.disable_auto_compactions &&
compaction_picker_->NeedsCompaction(current_->storage_info());
Rewritten system for scheduling background work Summary: When scaling to higher number of column families, the worst bottleneck was MaybeScheduleFlushOrCompaction(), which did a for loop over all column families while holding a mutex. This patch addresses the issue. The approach is similar to our earlier efforts: instead of a pull-model, where we do something for every column family, we can do a push-based model -- when we detect that column family is ready to be flushed/compacted, we add it to the flush_queue_/compaction_queue_. That way we don't need to loop over every column family in MaybeScheduleFlushOrCompaction. Here are the performance results: Command: ./db_bench --write_buffer_size=268435456 --db_write_buffer_size=268435456 --db=/fast-rocksdb-tmp/rocks_lots_of_cf --use_existing_db=0 --open_files=55000 --statistics=1 --histogram=1 --disable_data_sync=1 --max_write_buffer_number=2 --sync=0 --benchmarks=fillrandom --threads=16 --num_column_families=5000 --disable_wal=1 --max_background_flushes=16 --max_background_compactions=16 --level0_file_num_compaction_trigger=2 --level0_slowdown_writes_trigger=2 --level0_stop_writes_trigger=3 --hard_rate_limit=1 --num=33333333 --writes=33333333 Before the patch: fillrandom : 26.950 micros/op 37105 ops/sec; 4.1 MB/s After the patch: fillrandom : 17.404 micros/op 57456 ops/sec; 6.4 MB/s Next bottleneck is VersionSet::AddLiveFiles, which is painfully slow when we have a lot of files. This is coming in the next patch, but when I removed that code, here's what I got: fillrandom : 7.590 micros/op 131758 ops/sec; 14.6 MB/s Test Plan: make check two stress tests: Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 max_background_flushes=0, to verify that this case also works correctly ./db_stress --threads=30 --ops_per_thread=2000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=3 --max_background_compactions=3 --max_background_flushes=0 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: ljin, rven, yhchiang, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30123
2014-12-19 20:38:12 +01:00
}
Compaction* ColumnFamilyData::PickCompaction(
const MutableCFOptions& mutable_options,
const MutableDBOptions& mutable_db_options, LogBuffer* log_buffer) {
Fix corruption with intra-L0 on ingested files (#5958) Summary: ## Problem Description Our process was abort when it call `CheckConsistency`. And the information in `stderr` show that "`L0 files seqno 3001491972 3004797440 vs. 3002875611 3004524421` ". Here are the causes of the accident I investigated. * RocksDB will call `CheckConsistency` whenever `MANIFEST` file is update. It will check sequence number interval of every file, except files which were ingested. * When one file is ingested into RocksDB, it will be assigned the value of global sequence number, and the minimum and maximum seqno of this file are equal, which are both equal to global sequence number. * `CheckConsistency` determines whether the file is ingested by whether the smallest and largest seqno of an sstable file are equal. * If IntraL0Compaction picks one sst which was ingested just now and compacted it into another sst, the `smallest_seqno` of this new file will be smaller than his `largest_seqno`. * If more than one ingested file was ingested before memtable schedule flush, and they all compact into one new sstable file by `IntraL0Compaction`. The sequence interval of this new file will be included in the interval of the memtable. So `CheckConsistency` will return a `Corruption`. * If a sstable was ingested after the memtable was schedule to flush, which would assign a larger seqno to it than memtable. Then the file was compacted with other files (these files were all flushed before the memtable) in L0 into one file. This compaction start before the flush job of memtable start, but completed after the flush job finish. So this new file produced by the compaction (we call it s1) would have a larger interval of sequence number than the file produced by flush (we call it s2). **But there was still some data in s1 written into RocksDB before the s2, so it's possible that some data in s2 was cover by old data in s1.** Of course, it would also make a `Corruption` because of overlap of seqno. There is the relationship of the files: > s1.smallest_seqno < s2.smallest_seqno < s2.largest_seqno < s1.largest_seqno So I skip pick sst file which was ingested in function `FindIntraL0Compaction ` ## Reason Here is my bug report: https://github.com/facebook/rocksdb/issues/5913 There are two situations that can cause the check to fail. ### First situation: - First we ingest five external sst into Rocksdb, and they happened to be ingested in L0. and there had been some data in memtable, which make the smallest sequence number of memtable is less than which of sst that we ingest. - If there had been one compaction job which compacted sst from L0 to L1, `LevelCompactionPicker` would trigger a `IntraL0Compaction` which would compact this five sst from L0 to L0. We call this sst A, which was merged from five ingested sst. - Then some data was put into memtable, and memtable was flushed to L0. We called this sst B. - RocksDB check consistency , and find the `smallest_seqno` of B is less than that of A and crash. Because A was merged from five sst, the smallest sequence number of it was less than the biggest sequece number of itself, so RocksDB could not tell if A was produce by ingested. ### Secondary situaion - First we have flushed many sst in L0, we call them [s1, s2, s3]. - There is an immutable memtable request to be flushed, but because flush thread is busy, so it has not been picked. we call it m1. And at the moment, one sst is ingested into L0. We call it s4. Because s4 is ingested after m1 became immutable memtable, so it has a larger log sequence number than m1. - m1 is flushed in L0. because it is small, this flush job finish quickly. we call it s5. - [s1, s2, s3, s4] are compacted into one sst to L0, by IntraL0Compaction. We call it s6. - compacted 4@0 files to L0 - When s6 is added into manifest, the corruption happened. because the largest sequence number of s6 is equal to s4, and they are both larger than that of s5. But because s1 is older than m1, so the smallest sequence number of s6 is smaller than that of s5. - s6.smallest_seqno < s5.smallest_seqno < s5.largest_seqno < s6.largest_seqno Pull Request resolved: https://github.com/facebook/rocksdb/pull/5958 Differential Revision: D18601316 fbshipit-source-id: 5fe54b3c9af52a2e1400728f565e895cde1c7267
2019-11-20 00:07:49 +01:00
SequenceNumber earliest_mem_seqno =
std::min(mem_->GetEarliestSequenceNumber(),
imm_.current()->GetEarliestSequenceNumber(false));
auto* result = compaction_picker_->PickCompaction(
GetName(), mutable_options, mutable_db_options, current_->storage_info(),
log_buffer, earliest_mem_seqno);
if (result != nullptr) {
result->SetInputVersion(current_);
}
return result;
}
bool ColumnFamilyData::RangeOverlapWithCompaction(
const Slice& smallest_user_key, const Slice& largest_user_key,
int level) const {
return compaction_picker_->RangeOverlapWithCompaction(
smallest_user_key, largest_user_key, level);
}
Status ColumnFamilyData::RangesOverlapWithMemtables(
const autovector<Range>& ranges, SuperVersion* super_version,
bool allow_data_in_errors, bool* overlap) {
assert(overlap != nullptr);
*overlap = false;
// Create an InternalIterator over all unflushed memtables
Arena arena;
ReadOptions read_opts;
read_opts.total_order_seek = true;
MergeIteratorBuilder merge_iter_builder(&internal_comparator_, &arena);
merge_iter_builder.AddIterator(
super_version->mem->NewIterator(read_opts, &arena));
super_version->imm->AddIterators(read_opts, &merge_iter_builder);
ScopedArenaIterator memtable_iter(merge_iter_builder.Finish());
auto read_seq = super_version->current->version_set()->LastSequence();
ReadRangeDelAggregator range_del_agg(&internal_comparator_, read_seq);
auto* active_range_del_iter =
super_version->mem->NewRangeTombstoneIterator(read_opts, read_seq);
range_del_agg.AddTombstones(
std::unique_ptr<FragmentedRangeTombstoneIterator>(active_range_del_iter));
Status status;
status = super_version->imm->AddRangeTombstoneIterators(
read_opts, nullptr /* arena */, &range_del_agg);
// AddRangeTombstoneIterators always return Status::OK.
assert(status.ok());
for (size_t i = 0; i < ranges.size() && status.ok() && !*overlap; ++i) {
auto* vstorage = super_version->current->storage_info();
auto* ucmp = vstorage->InternalComparator()->user_comparator();
InternalKey range_start(ranges[i].start, kMaxSequenceNumber,
kValueTypeForSeek);
memtable_iter->Seek(range_start.Encode());
status = memtable_iter->status();
ParsedInternalKey seek_result;
if (status.ok() && memtable_iter->Valid()) {
status = ParseInternalKey(memtable_iter->key(), &seek_result,
allow_data_in_errors);
}
if (status.ok()) {
if (memtable_iter->Valid() &&
ucmp->Compare(seek_result.user_key, ranges[i].limit) <= 0) {
*overlap = true;
} else if (range_del_agg.IsRangeOverlapped(ranges[i].start,
ranges[i].limit)) {
*overlap = true;
}
}
}
return status;
}
const int ColumnFamilyData::kCompactAllLevels = -1;
const int ColumnFamilyData::kCompactToBaseLevel = -2;
Compaction* ColumnFamilyData::CompactRange(
const MutableCFOptions& mutable_cf_options,
const MutableDBOptions& mutable_db_options, int input_level,
int output_level, const CompactRangeOptions& compact_range_options,
const InternalKey* begin, const InternalKey* end,
InternalKey** compaction_end, bool* conflict,
uint64_t max_file_num_to_ignore) {
auto* result = compaction_picker_->CompactRange(
GetName(), mutable_cf_options, mutable_db_options,
current_->storage_info(), input_level, output_level,
compact_range_options, begin, end, compaction_end, conflict,
max_file_num_to_ignore);
if (result != nullptr) {
result->SetInputVersion(current_);
}
return result;
}
SuperVersion* ColumnFamilyData::GetReferencedSuperVersion(DBImpl* db) {
SuperVersion* sv = GetThreadLocalSuperVersion(db);
sv->Ref();
if (!ReturnThreadLocalSuperVersion(sv)) {
// This Unref() corresponds to the Ref() in GetThreadLocalSuperVersion()
// when the thread-local pointer was populated. So, the Ref() earlier in
// this function still prevents the returned SuperVersion* from being
// deleted out from under the caller.
sv->Unref();
}
return sv;
}
SuperVersion* ColumnFamilyData::GetThreadLocalSuperVersion(DBImpl* db) {
// The SuperVersion is cached in thread local storage to avoid acquiring
// mutex when SuperVersion does not change since the last use. When a new
// SuperVersion is installed, the compaction or flush thread cleans up
// cached SuperVersion in all existing thread local storage. To avoid
// acquiring mutex for this operation, we use atomic Swap() on the thread
// local pointer to guarantee exclusive access. If the thread local pointer
// is being used while a new SuperVersion is installed, the cached
// SuperVersion can become stale. In that case, the background thread would
// have swapped in kSVObsolete. We re-check the value at when returning
// SuperVersion back to thread local, with an atomic compare and swap.
// The superversion will need to be released if detected to be stale.
void* ptr = local_sv_->Swap(SuperVersion::kSVInUse);
// Invariant:
// (1) Scrape (always) installs kSVObsolete in ThreadLocal storage
// (2) the Swap above (always) installs kSVInUse, ThreadLocal storage
// should only keep kSVInUse before ReturnThreadLocalSuperVersion call
// (if no Scrape happens).
assert(ptr != SuperVersion::kSVInUse);
SuperVersion* sv = static_cast<SuperVersion*>(ptr);
if (sv == SuperVersion::kSVObsolete ||
sv->version_number != super_version_number_.load()) {
RecordTick(ioptions_.statistics, NUMBER_SUPERVERSION_ACQUIRES);
SuperVersion* sv_to_delete = nullptr;
if (sv && sv->Unref()) {
RecordTick(ioptions_.statistics, NUMBER_SUPERVERSION_CLEANUPS);
db->mutex()->Lock();
// NOTE: underlying resources held by superversion (sst files) might
// not be released until the next background job.
sv->Cleanup();
if (db->immutable_db_options().avoid_unnecessary_blocking_io) {
db->AddSuperVersionsToFreeQueue(sv);
db->SchedulePurge();
} else {
sv_to_delete = sv;
}
} else {
db->mutex()->Lock();
}
sv = super_version_->Ref();
db->mutex()->Unlock();
delete sv_to_delete;
}
assert(sv != nullptr);
return sv;
}
bool ColumnFamilyData::ReturnThreadLocalSuperVersion(SuperVersion* sv) {
assert(sv != nullptr);
// Put the SuperVersion back
void* expected = SuperVersion::kSVInUse;
if (local_sv_->CompareAndSwap(static_cast<void*>(sv), expected)) {
// When we see kSVInUse in the ThreadLocal, we are sure ThreadLocal
2015-04-25 11:14:27 +02:00
// storage has not been altered and no Scrape has happened. The
// SuperVersion is still current.
return true;
} else {
// ThreadLocal scrape happened in the process of this GetImpl call (after
// thread local Swap() at the beginning and before CompareAndSwap()).
// This means the SuperVersion it holds is obsolete.
assert(expected == SuperVersion::kSVObsolete);
}
return false;
}
void ColumnFamilyData::InstallSuperVersion(
SuperVersionContext* sv_context, InstrumentedMutex* db_mutex) {
db_mutex->AssertHeld();
return InstallSuperVersion(sv_context, db_mutex, mutable_cf_options_);
}
void ColumnFamilyData::InstallSuperVersion(
SuperVersionContext* sv_context, InstrumentedMutex* db_mutex,
const MutableCFOptions& mutable_cf_options) {
SuperVersion* new_superversion = sv_context->new_superversion.release();
new_superversion->db_mutex = db_mutex;
new_superversion->mutable_cf_options = mutable_cf_options;
new_superversion->Init(this, mem_, imm_.current(), current_);
SuperVersion* old_superversion = super_version_;
super_version_ = new_superversion;
++super_version_number_;
super_version_->version_number = super_version_number_;
super_version_->write_stall_condition =
RecalculateWriteStallConditions(mutable_cf_options);
if (old_superversion != nullptr) {
// Reset SuperVersions cached in thread local storage.
// This should be done before old_superversion->Unref(). That's to ensure
// that local_sv_ never holds the last reference to SuperVersion, since
// it has no means to safely do SuperVersion cleanup.
ResetThreadLocalSuperVersions();
if (old_superversion->mutable_cf_options.write_buffer_size !=
mutable_cf_options.write_buffer_size) {
mem_->UpdateWriteBufferSize(mutable_cf_options.write_buffer_size);
}
if (old_superversion->write_stall_condition !=
new_superversion->write_stall_condition) {
sv_context->PushWriteStallNotification(
old_superversion->write_stall_condition,
new_superversion->write_stall_condition, GetName(), ioptions());
}
if (old_superversion->Unref()) {
old_superversion->Cleanup();
sv_context->superversions_to_free.push_back(old_superversion);
}
}
}
void ColumnFamilyData::ResetThreadLocalSuperVersions() {
autovector<void*> sv_ptrs;
local_sv_->Scrape(&sv_ptrs, SuperVersion::kSVObsolete);
for (auto ptr : sv_ptrs) {
assert(ptr);
if (ptr == SuperVersion::kSVInUse) {
continue;
}
auto sv = static_cast<SuperVersion*>(ptr);
bool was_last_ref __attribute__((__unused__));
was_last_ref = sv->Unref();
// sv couldn't have been the last reference because
// ResetThreadLocalSuperVersions() is called before
// unref'ing super_version_.
assert(!was_last_ref);
}
}
Status ColumnFamilyData::ValidateOptions(
const DBOptions& db_options, const ColumnFamilyOptions& cf_options) {
Status s;
s = CheckCompressionSupported(cf_options);
if (s.ok() && db_options.allow_concurrent_memtable_write) {
s = CheckConcurrentWritesSupported(cf_options);
}
if (s.ok() && db_options.unordered_write &&
cf_options.max_successive_merges != 0) {
s = Status::InvalidArgument(
"max_successive_merges > 0 is incompatible with unordered_write");
}
if (s.ok()) {
s = CheckCFPathsSupported(db_options, cf_options);
}
if (!s.ok()) {
return s;
}
if (cf_options.ttl > 0 && cf_options.ttl != kDefaultTtl) {
if (!cf_options.table_factory->IsInstanceOf(
TableFactory::kBlockBasedTableName())) {
return Status::NotSupported(
"TTL is only supported in Block-Based Table format. ");
}
}
Auto enable Periodic Compactions if a Compaction Filter is used (#5865) Summary: - Periodic compactions are auto-enabled if a compaction filter or a compaction filter factory is set, in Level Compaction. - The default value of `periodic_compaction_seconds` is changed to UINT64_MAX, which lets RocksDB auto-tune periodic compactions as needed. An explicit value of 0 will still work as before ie. to disable periodic compactions completely. For now, on seeing a compaction filter along with a UINT64_MAX value for `periodic_compaction_seconds`, RocksDB will make SST files older than 30 days to go through periodic copmactions. Some RocksDB users make use of compaction filters to control when their data can be deleted, usually with a custom TTL logic. But it is occasionally possible that the compactions get delayed by considerable time due to factors like low writes to a key range, data reaching bottom level, etc before the TTL expiry. Periodic Compactions feature was originally built to help such cases. Now periodic compactions are auto enabled by default when compaction filters or compaction filter factories are used, as it is generally helpful to all cases to collect garbage. `periodic_compaction_seconds` is set to a large value, 30 days, in `SanitizeOptions` when RocksDB sees that a `compaction_filter` or `compaction_filter_factory` is used. This is done only for Level Compaction style. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5865 Test Plan: - Added a new test `DBCompactionTest.LevelPeriodicCompactionWithCompactionFilters` to make sure that `periodic_compaction_seconds` is set if either `compaction_filter` or `compaction_filter_factory` options are set. - `COMPILE_WITH_ASAN=1 make check` Differential Revision: D17659180 Pulled By: sagar0 fbshipit-source-id: 4887b9cf2e53cf2dc93a7b658c6b15e1181217ee
2019-10-29 23:04:26 +01:00
if (cf_options.periodic_compaction_seconds > 0 &&
cf_options.periodic_compaction_seconds != kDefaultPeriodicCompSecs) {
if (!cf_options.table_factory->IsInstanceOf(
TableFactory::kBlockBasedTableName())) {
return Status::NotSupported(
"Periodic Compaction is only supported in "
"Block-Based Table format. ");
}
}
Integrated blob garbage collection: relocate blobs (#7694) Summary: The patch adds basic garbage collection support to the integrated BlobDB implementation. Valid blobs residing in the oldest blob files are relocated as they are encountered during compaction. The threshold that determines which blob files qualify is computed based on the configuration option `blob_garbage_collection_age_cutoff`, which was introduced in https://github.com/facebook/rocksdb/issues/7661 . Once a blob is retrieved for the purposes of relocation, it passes through the same logic that extracts large values to blob files in general. This means that if, for instance, the size threshold for key-value separation (`min_blob_size`) got changed or writing blob files got disabled altogether, it is possible for the value to be moved back into the LSM tree. In particular, one way to re-inline all blob values if needed would be to perform a full manual compaction with `enable_blob_files` set to `false`, `enable_blob_garbage_collection` set to `true`, and `blob_file_garbage_collection_age_cutoff` set to `1.0`. Some TODOs that I plan to address in separate PRs: 1) We'll have to measure the amount of new garbage in each blob file and log `BlobFileGarbage` entries as part of the compaction job's `VersionEdit`. (For the time being, blob files are cleaned up solely based on the `oldest_blob_file_number` relationships.) 2) When compression is used for blobs, the compression type hasn't changed, and the blob still qualifies for being written to a blob file, we can simply copy the compressed blob to the new file instead of going through decompression and compression. 3) We need to update the formula for computing write amplification to account for the amount of data read from blob files as part of GC. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7694 Test Plan: `make check` Reviewed By: riversand963 Differential Revision: D25069663 Pulled By: ltamasi fbshipit-source-id: bdfa8feb09afcf5bca3b4eba2ba72ce2f15cd06a
2020-11-24 06:07:01 +01:00
if (cf_options.enable_blob_garbage_collection &&
(cf_options.blob_garbage_collection_age_cutoff < 0.0 ||
cf_options.blob_garbage_collection_age_cutoff > 1.0)) {
return Status::InvalidArgument(
"The age cutoff for blob garbage collection should be in the range "
"[0.0, 1.0].");
}
return s;
}
#ifndef ROCKSDB_LITE
Status ColumnFamilyData::SetOptions(
const DBOptions& db_options,
const std::unordered_map<std::string, std::string>& options_map) {
MutableCFOptions new_mutable_cf_options;
Status s =
GetMutableOptionsFromStrings(mutable_cf_options_, options_map,
ioptions_.info_log, &new_mutable_cf_options);
if (s.ok()) {
ColumnFamilyOptions cf_options =
BuildColumnFamilyOptions(initial_cf_options_, new_mutable_cf_options);
s = ValidateOptions(db_options, cf_options);
}
if (s.ok()) {
mutable_cf_options_ = new_mutable_cf_options;
mutable_cf_options_.RefreshDerivedOptions(ioptions_);
}
return s;
}
#endif // ROCKSDB_LITE
// REQUIRES: DB mutex held
Env::WriteLifeTimeHint ColumnFamilyData::CalculateSSTWriteHint(int level) {
if (initial_cf_options_.compaction_style != kCompactionStyleLevel) {
return Env::WLTH_NOT_SET;
}
if (level == 0) {
return Env::WLTH_MEDIUM;
}
int base_level = current_->storage_info()->base_level();
// L1: medium, L2: long, ...
if (level - base_level >= 2) {
return Env::WLTH_EXTREME;
} else if (level < base_level) {
// There is no restriction which prevents level passed in to be smaller
// than base_level.
return Env::WLTH_MEDIUM;
}
return static_cast<Env::WriteLifeTimeHint>(level - base_level +
static_cast<int>(Env::WLTH_MEDIUM));
}
Status ColumnFamilyData::AddDirectories(
std::map<std::string, std::shared_ptr<FSDirectory>>* created_dirs) {
Status s;
assert(created_dirs != nullptr);
assert(data_dirs_.empty());
for (auto& p : ioptions_.cf_paths) {
auto existing_dir = created_dirs->find(p.path);
if (existing_dir == created_dirs->end()) {
std::unique_ptr<FSDirectory> path_directory;
s = DBImpl::CreateAndNewDirectory(ioptions_.fs, p.path, &path_directory);
if (!s.ok()) {
return s;
}
assert(path_directory != nullptr);
data_dirs_.emplace_back(path_directory.release());
(*created_dirs)[p.path] = data_dirs_.back();
} else {
data_dirs_.emplace_back(existing_dir->second);
}
}
assert(data_dirs_.size() == ioptions_.cf_paths.size());
return s;
}
FSDirectory* ColumnFamilyData::GetDataDir(size_t path_id) const {
if (data_dirs_.empty()) {
return nullptr;
}
assert(path_id < data_dirs_.size());
return data_dirs_[path_id].get();
}
ColumnFamilySet::ColumnFamilySet(const std::string& dbname,
const ImmutableDBOptions* db_options,
Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
2019-12-13 23:47:08 +01:00
const FileOptions& file_options,
Cache* table_cache,
WriteBufferManager* _write_buffer_manager,
WriteController* _write_controller,
BlockCacheTracer* const block_cache_tracer,
const std::shared_ptr<IOTracer>& io_tracer)
: max_column_family_(0),
dummy_cfd_(new ColumnFamilyData(
ColumnFamilyData::kDummyColumnFamilyDataId, "", nullptr, nullptr,
nullptr, ColumnFamilyOptions(), *db_options, file_options, nullptr,
block_cache_tracer, io_tracer)),
default_cfd_cache_(nullptr),
db_name_(dbname),
db_options_(db_options),
Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
2019-12-13 23:47:08 +01:00
file_options_(file_options),
table_cache_(table_cache),
write_buffer_manager_(_write_buffer_manager),
write_controller_(_write_controller),
block_cache_tracer_(block_cache_tracer),
io_tracer_(io_tracer) {
// initialize linked list
dummy_cfd_->prev_ = dummy_cfd_;
dummy_cfd_->next_ = dummy_cfd_;
}
ColumnFamilySet::~ColumnFamilySet() {
while (column_family_data_.size() > 0) {
// cfd destructor will delete itself from column_family_data_
auto cfd = column_family_data_.begin()->second;
bool last_ref __attribute__((__unused__));
last_ref = cfd->UnrefAndTryDelete();
assert(last_ref);
}
bool dummy_last_ref __attribute__((__unused__));
dummy_last_ref = dummy_cfd_->UnrefAndTryDelete();
assert(dummy_last_ref);
}
ColumnFamilyData* ColumnFamilySet::GetDefault() const {
assert(default_cfd_cache_ != nullptr);
return default_cfd_cache_;
}
ColumnFamilyData* ColumnFamilySet::GetColumnFamily(uint32_t id) const {
auto cfd_iter = column_family_data_.find(id);
if (cfd_iter != column_family_data_.end()) {
return cfd_iter->second;
} else {
return nullptr;
}
}
ColumnFamilyData* ColumnFamilySet::GetColumnFamily(const std::string& name)
const {
auto cfd_iter = column_families_.find(name);
if (cfd_iter != column_families_.end()) {
auto cfd = GetColumnFamily(cfd_iter->second);
assert(cfd != nullptr);
return cfd;
} else {
return nullptr;
}
}
uint32_t ColumnFamilySet::GetNextColumnFamilyID() {
return ++max_column_family_;
}
uint32_t ColumnFamilySet::GetMaxColumnFamily() { return max_column_family_; }
void ColumnFamilySet::UpdateMaxColumnFamily(uint32_t new_max_column_family) {
max_column_family_ = std::max(new_max_column_family, max_column_family_);
}
size_t ColumnFamilySet::NumberOfColumnFamilies() const {
return column_families_.size();
}
2015-01-06 21:44:21 +01:00
// under a DB mutex AND write thread
ColumnFamilyData* ColumnFamilySet::CreateColumnFamily(
const std::string& name, uint32_t id, Version* dummy_versions,
const ColumnFamilyOptions& options) {
assert(column_families_.find(name) == column_families_.end());
ColumnFamilyData* new_cfd = new ColumnFamilyData(
id, name, dummy_versions, table_cache_, write_buffer_manager_, options,
*db_options_, file_options_, this, block_cache_tracer_, io_tracer_);
column_families_.insert({name, id});
column_family_data_.insert({id, new_cfd});
max_column_family_ = std::max(max_column_family_, id);
// add to linked list
new_cfd->next_ = dummy_cfd_;
auto prev = dummy_cfd_->prev_;
new_cfd->prev_ = prev;
prev->next_ = new_cfd;
dummy_cfd_->prev_ = new_cfd;
if (id == 0) {
default_cfd_cache_ = new_cfd;
}
return new_cfd;
}
// REQUIRES: DB mutex held
void ColumnFamilySet::FreeDeadColumnFamilies() {
autovector<ColumnFamilyData*> to_delete;
for (auto cfd = dummy_cfd_->next_; cfd != dummy_cfd_; cfd = cfd->next_) {
if (cfd->refs_.load(std::memory_order_relaxed) == 0) {
to_delete.push_back(cfd);
}
}
for (auto cfd : to_delete) {
// this is very rare, so it's not a problem that we do it under a mutex
delete cfd;
}
}
2015-01-06 21:44:21 +01:00
// under a DB mutex AND from a write thread
void ColumnFamilySet::RemoveColumnFamily(ColumnFamilyData* cfd) {
auto cfd_iter = column_family_data_.find(cfd->GetID());
assert(cfd_iter != column_family_data_.end());
column_family_data_.erase(cfd_iter);
column_families_.erase(cfd->GetName());
}
2015-01-06 21:44:21 +01:00
// under a DB mutex OR from a write thread
bool ColumnFamilyMemTablesImpl::Seek(uint32_t column_family_id) {
if (column_family_id == 0) {
// optimization for common case
current_ = column_family_set_->GetDefault();
} else {
current_ = column_family_set_->GetColumnFamily(column_family_id);
}
handle_.SetCFD(current_);
return current_ != nullptr;
}
uint64_t ColumnFamilyMemTablesImpl::GetLogNumber() const {
assert(current_ != nullptr);
return current_->GetLogNumber();
}
MemTable* ColumnFamilyMemTablesImpl::GetMemTable() const {
assert(current_ != nullptr);
return current_->mem();
}
ColumnFamilyHandle* ColumnFamilyMemTablesImpl::GetColumnFamilyHandle() {
assert(current_ != nullptr);
return &handle_;
}
uint32_t GetColumnFamilyID(ColumnFamilyHandle* column_family) {
uint32_t column_family_id = 0;
if (column_family != nullptr) {
auto cfh = static_cast_with_check<ColumnFamilyHandleImpl>(column_family);
column_family_id = cfh->GetID();
}
return column_family_id;
}
const Comparator* GetColumnFamilyUserComparator(
ColumnFamilyHandle* column_family) {
if (column_family != nullptr) {
return column_family->GetComparator();
}
return nullptr;
}
} // namespace ROCKSDB_NAMESPACE