rocksdb/table/table_builder.h
Peter Dillinger fc9d4071f0 Fast path for detecting unchanged prefix_extractor (#9407)
Summary:
Fixes a major performance regression in 6.26, where
extra CPU is spent in SliceTransform::AsString when reads involve
a prefix_extractor (Get, MultiGet, Seek). Common case performance
is now better than 6.25.

This change creates a "fast path" for verifying that the current prefix
extractor is unchanged and compatible with what was used to
generate a table file. This fast path detects the common case by
pointer comparison on the current prefix_extractor and a "known
good" prefix extractor (if applicable) that is saved at the time the
table reader is opened. The "known good" prefix extractor is saved
as another shared_ptr copy (in an existing field, however) to ensure
the pointer is not recycled.

When the prefix_extractor has changed to a different instance but
same compatible configuration (rare, odd), performance is still a
regression compared to 6.25, but this is likely acceptable because
of the oddity of such a case. The performance of incompatible
prefix_extractor is essentially unchanged.

Also fixed a minor case (ForwardIterator) where a prefix_extractor
could be used via a raw pointer after being freed as a shared_ptr,
if replaced via SetOptions.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9407

Test Plan:
## Performance
Populate DB with `TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom -num=10000000 -disable_wal=1 -write_buffer_size=10000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -prefix_size=12`

Running head-to-head comparisons simultaneously with `TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -use_existing_db -readonly -benchmarks=seekrandom -num=10000000 -duration=20 -disable_wal=1 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -prefix_size=12`

Below each is compared by ops/sec vs. baseline which is version 6.25 (multiple baseline runs because of variable machine load)

v6.26: 4833 vs. 6698 (<- major regression!)
v6.27: 4737 vs. 6397 (still)
New: 6704 vs. 6461 (better than baseline in common case)
Disabled fastpath: 4843 vs. 6389 (e.g. if prefix extractor instance changes but is still compatible)
Changed prefix size (no usable filter) in new: 787 vs. 5927
Changed prefix size (no usable filter) in new & baseline: 773 vs. 784

Reviewed By: mrambacher

Differential Revision: D33677812

Pulled By: pdillinger

fbshipit-source-id: 571d9711c461fb97f957378a061b7e7dbc4d6a76
2022-01-21 11:37:46 -08:00

228 lines
8.8 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <stdint.h>
#include <string>
#include <utility>
#include <vector>
#include "db/dbformat.h"
#include "db/table_properties_collector.h"
#include "file/writable_file_writer.h"
#include "options/cf_options.h"
#include "rocksdb/options.h"
#include "rocksdb/table_properties.h"
#include "trace_replay/block_cache_tracer.h"
namespace ROCKSDB_NAMESPACE {
class Slice;
class Status;
struct TableReaderOptions {
// @param skip_filters Disables loading/accessing the filter block
TableReaderOptions(
const ImmutableOptions& _ioptions,
const std::shared_ptr<const SliceTransform>& _prefix_extractor,
const EnvOptions& _env_options,
const InternalKeyComparator& _internal_comparator,
bool _skip_filters = false, bool _immortal = false,
bool _force_direct_prefetch = false, int _level = -1,
BlockCacheTracer* const _block_cache_tracer = nullptr,
size_t _max_file_size_for_l0_meta_pin = 0,
const std::string& _cur_db_session_id = "", uint64_t _cur_file_num = 0)
: TableReaderOptions(
_ioptions, _prefix_extractor, _env_options, _internal_comparator,
_skip_filters, _immortal, _force_direct_prefetch, _level,
0 /* _largest_seqno */, _block_cache_tracer,
_max_file_size_for_l0_meta_pin, _cur_db_session_id, _cur_file_num) {
}
// @param skip_filters Disables loading/accessing the filter block
TableReaderOptions(
const ImmutableOptions& _ioptions,
const std::shared_ptr<const SliceTransform>& _prefix_extractor,
const EnvOptions& _env_options,
const InternalKeyComparator& _internal_comparator, bool _skip_filters,
bool _immortal, bool _force_direct_prefetch, int _level,
SequenceNumber _largest_seqno,
BlockCacheTracer* const _block_cache_tracer,
size_t _max_file_size_for_l0_meta_pin,
const std::string& _cur_db_session_id, uint64_t _cur_file_num)
: ioptions(_ioptions),
prefix_extractor(_prefix_extractor),
env_options(_env_options),
internal_comparator(_internal_comparator),
skip_filters(_skip_filters),
immortal(_immortal),
force_direct_prefetch(_force_direct_prefetch),
level(_level),
largest_seqno(_largest_seqno),
block_cache_tracer(_block_cache_tracer),
max_file_size_for_l0_meta_pin(_max_file_size_for_l0_meta_pin),
cur_db_session_id(_cur_db_session_id),
cur_file_num(_cur_file_num) {}
const ImmutableOptions& ioptions;
const std::shared_ptr<const SliceTransform>& prefix_extractor;
const EnvOptions& env_options;
const InternalKeyComparator& internal_comparator;
// This is only used for BlockBasedTable (reader)
bool skip_filters;
// Whether the table will be valid as long as the DB is open
bool immortal;
// When data prefetching is needed, even if direct I/O is off, read data to
// fetch into RocksDB's buffer, rather than relying
// RandomAccessFile::Prefetch().
bool force_direct_prefetch;
// What level this table/file is on, -1 for "not set, don't know." Used
// for level-specific statistics.
int level;
// largest seqno in the table
SequenceNumber largest_seqno;
BlockCacheTracer* const block_cache_tracer;
// Largest L0 file size whose meta-blocks may be pinned (can be zero when
// unknown).
const size_t max_file_size_for_l0_meta_pin;
std::string cur_db_session_id;
uint64_t cur_file_num;
};
struct TableBuilderOptions {
TableBuilderOptions(
const ImmutableOptions& _ioptions, const MutableCFOptions& _moptions,
const InternalKeyComparator& _internal_comparator,
const IntTblPropCollectorFactories* _int_tbl_prop_collector_factories,
CompressionType _compression_type,
const CompressionOptions& _compression_opts, uint32_t _column_family_id,
const std::string& _column_family_name, int _level,
bool _is_bottommost = false,
TableFileCreationReason _reason = TableFileCreationReason::kMisc,
const uint64_t _creation_time = 0, const int64_t _oldest_key_time = 0,
const uint64_t _file_creation_time = 0, const std::string& _db_id = "",
const std::string& _db_session_id = "",
const uint64_t _target_file_size = 0, const uint64_t _cur_file_num = 0)
: ioptions(_ioptions),
moptions(_moptions),
internal_comparator(_internal_comparator),
int_tbl_prop_collector_factories(_int_tbl_prop_collector_factories),
compression_type(_compression_type),
compression_opts(_compression_opts),
column_family_id(_column_family_id),
column_family_name(_column_family_name),
creation_time(_creation_time),
oldest_key_time(_oldest_key_time),
target_file_size(_target_file_size),
file_creation_time(_file_creation_time),
db_id(_db_id),
db_session_id(_db_session_id),
level_at_creation(_level),
is_bottommost(_is_bottommost),
reason(_reason),
cur_file_num(_cur_file_num) {}
const ImmutableOptions& ioptions;
const MutableCFOptions& moptions;
const InternalKeyComparator& internal_comparator;
const IntTblPropCollectorFactories* int_tbl_prop_collector_factories;
const CompressionType compression_type;
const CompressionOptions& compression_opts;
const uint32_t column_family_id;
const std::string& column_family_name;
const uint64_t creation_time;
const int64_t oldest_key_time;
const uint64_t target_file_size;
const uint64_t file_creation_time;
const std::string db_id;
const std::string db_session_id;
// BEGIN for FilterBuildingContext
const int level_at_creation;
const bool is_bottommost;
const TableFileCreationReason reason;
// END for FilterBuildingContext
// XXX: only used by BlockBasedTableBuilder for SstFileWriter. If you
// want to skip filters, that should be (for example) null filter_policy
// in the table options of the ioptions.table_factory
bool skip_filters = false;
const uint64_t cur_file_num;
};
// TableBuilder provides the interface used to build a Table
// (an immutable and sorted map from keys to values).
//
// Multiple threads can invoke const methods on a TableBuilder without
// external synchronization, but if any of the threads may call a
// non-const method, all threads accessing the same TableBuilder must use
// external synchronization.
class TableBuilder {
public:
// REQUIRES: Either Finish() or Abandon() has been called.
virtual ~TableBuilder() {}
// Add key,value to the table being constructed.
// REQUIRES: key is after any previously added key according to comparator.
// REQUIRES: Finish(), Abandon() have not been called
virtual void Add(const Slice& key, const Slice& value) = 0;
// Return non-ok iff some error has been detected.
virtual Status status() const = 0;
// Return non-ok iff some error happens during IO.
virtual IOStatus io_status() const = 0;
// Finish building the table.
// REQUIRES: Finish(), Abandon() have not been called
virtual Status Finish() = 0;
// Indicate that the contents of this builder should be abandoned.
// If the caller is not going to call Finish(), it must call Abandon()
// before destroying this builder.
// REQUIRES: Finish(), Abandon() have not been called
virtual void Abandon() = 0;
// Number of calls to Add() so far.
virtual uint64_t NumEntries() const = 0;
// Whether the output file is completely empty. It has neither entries
// or tombstones.
virtual bool IsEmpty() const {
return NumEntries() == 0 && GetTableProperties().num_range_deletions == 0;
}
// Size of the file generated so far. If invoked after a successful
// Finish() call, returns the size of the final generated file.
virtual uint64_t FileSize() const = 0;
// Estimated size of the file generated so far. This is used when
// FileSize() cannot estimate final SST size, e.g. parallel compression
// is enabled.
virtual uint64_t EstimatedFileSize() const { return FileSize(); }
// If the user defined table properties collector suggest the file to
// be further compacted.
virtual bool NeedCompact() const { return false; }
// Returns table properties
virtual TableProperties GetTableProperties() const = 0;
// Return file checksum
virtual std::string GetFileChecksum() const = 0;
// Return file checksum function name
virtual const char* GetFileChecksumFuncName() const = 0;
};
} // namespace ROCKSDB_NAMESPACE