62f70f6d14
Summary: Our previous approach was to train one compression dictionary per compaction, using the first output SST to train a dictionary, and then applying it on subsequent SSTs in the same compaction. While this was great for minimizing CPU/memory/I/O overhead, it did not achieve good compression ratios in practice. In our most promising potential use case, moderate reductions in a dictionary's scope make a major difference on compression ratio. So, this PR changes compression dictionary to be scoped per-SST. It accepts the tradeoff during table building to use more memory and CPU. Important changes include: - The `BlockBasedTableBuilder` has a new state when dictionary compression is in-use: `kBuffered`. In that state it accumulates uncompressed data in-memory whenever `Add` is called. - After accumulating target file size bytes or calling `BlockBasedTableBuilder::Finish`, a `BlockBasedTableBuilder` moves to the `kUnbuffered` state. The transition (`EnterUnbuffered()`) involves sampling the buffered data, training a dictionary, and compressing/writing out all buffered data. In the `kUnbuffered` state, a `BlockBasedTableBuilder` behaves the same as before -- blocks are compressed/written out as soon as they fill up. - Samples are now whole uncompressed data blocks, except the final sample may be a partial data block so we don't breach the user's configured `max_dict_bytes` or `zstd_max_train_bytes`. The dictionary trainer is supposed to work better when we pass it real units of compression. Previously we were passing 64-byte KV samples which was not realistic. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4952 Differential Revision: D13967980 Pulled By: ajkr fbshipit-source-id: 82bea6f7537e1529c7a1a4cdee84585f5949300f
85 lines
3.6 KiB
C++
85 lines
3.6 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include <string>
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#include <utility>
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#include <vector>
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#include "db/range_tombstone_fragmenter.h"
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#include "db/table_properties_collector.h"
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#include "options/cf_options.h"
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#include "rocksdb/comparator.h"
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#include "rocksdb/env.h"
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#include "rocksdb/listener.h"
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#include "rocksdb/options.h"
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#include "rocksdb/status.h"
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#include "rocksdb/table_properties.h"
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#include "rocksdb/types.h"
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#include "table/scoped_arena_iterator.h"
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#include "util/event_logger.h"
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namespace rocksdb {
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struct Options;
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struct FileMetaData;
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class Env;
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struct EnvOptions;
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class Iterator;
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class SnapshotChecker;
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class TableCache;
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class VersionEdit;
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class TableBuilder;
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class WritableFileWriter;
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class InternalStats;
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// @param column_family_name Name of the column family that is also identified
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// by column_family_id, or empty string if unknown. It must outlive the
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// TableBuilder returned by this function.
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TableBuilder* NewTableBuilder(
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const ImmutableCFOptions& options, const MutableCFOptions& moptions,
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const InternalKeyComparator& internal_comparator,
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const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
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int_tbl_prop_collector_factories,
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uint32_t column_family_id, const std::string& column_family_name,
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WritableFileWriter* file, const CompressionType compression_type,
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const CompressionOptions& compression_opts, int level,
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const bool skip_filters = false, const uint64_t creation_time = 0,
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const uint64_t oldest_key_time = 0, const bool is_bottommost_level = false,
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const uint64_t target_file_size = 0);
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// Build a Table file from the contents of *iter. The generated file
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// will be named according to number specified in meta. On success, the rest of
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// *meta will be filled with metadata about the generated table.
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// If no data is present in *iter, meta->file_size will be set to
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// zero, and no Table file will be produced.
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//
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// @param column_family_name Name of the column family that is also identified
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// by column_family_id, or empty string if unknown.
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extern Status BuildTable(
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const std::string& dbname, Env* env, const ImmutableCFOptions& options,
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const MutableCFOptions& mutable_cf_options, const EnvOptions& env_options,
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TableCache* table_cache, InternalIterator* iter,
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std::vector<std::unique_ptr<FragmentedRangeTombstoneIterator>>
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range_del_iters,
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FileMetaData* meta, const InternalKeyComparator& internal_comparator,
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const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
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int_tbl_prop_collector_factories,
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uint32_t column_family_id, const std::string& column_family_name,
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std::vector<SequenceNumber> snapshots,
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SequenceNumber earliest_write_conflict_snapshot,
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SnapshotChecker* snapshot_checker, const CompressionType compression,
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const CompressionOptions& compression_opts, bool paranoid_file_checks,
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InternalStats* internal_stats, TableFileCreationReason reason,
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EventLogger* event_logger = nullptr, int job_id = 0,
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const Env::IOPriority io_priority = Env::IO_HIGH,
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TableProperties* table_properties = nullptr, int level = -1,
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const uint64_t creation_time = 0, const uint64_t oldest_key_time = 0,
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Env::WriteLifeTimeHint write_hint = Env::WLTH_NOT_SET);
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} // namespace rocksdb
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