rocksdb/table/block_based/block_builder.h
Ziyue Yang 03a781a90c Add pipelined & parallel compression optimization (#6262)
Summary:
This PR adds support for pipelined & parallel compression optimization for `BlockBasedTableBuilder`. This optimization makes block building, block compression and block appending a pipeline, and uses multiple threads to accelerate block compression. Users can set `CompressionOptions::parallel_threads` greater than 1 to enable compression parallelism.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6262

Reviewed By: ajkr

Differential Revision: D20651306

fbshipit-source-id: 62125590a9c15b6d9071def9dc72589c1696a4cb
2020-04-01 16:40:18 -07:00

79 lines
3 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 <vector>
#include <stdint.h>
#include "rocksdb/slice.h"
#include "rocksdb/table.h"
#include "table/block_based/data_block_hash_index.h"
namespace ROCKSDB_NAMESPACE {
class BlockBuilder {
public:
BlockBuilder(const BlockBuilder&) = delete;
void operator=(const BlockBuilder&) = delete;
explicit BlockBuilder(int block_restart_interval,
bool use_delta_encoding = true,
bool use_value_delta_encoding = false,
BlockBasedTableOptions::DataBlockIndexType index_type =
BlockBasedTableOptions::kDataBlockBinarySearch,
double data_block_hash_table_util_ratio = 0.75);
// Reset the contents as if the BlockBuilder was just constructed.
void Reset();
// Swap the contents in BlockBuilder with buffer, then reset the BlockBuilder.
void SwapAndReset(std::string& buffer);
// REQUIRES: Finish() has not been called since the last call to Reset().
// REQUIRES: key is larger than any previously added key
void Add(const Slice& key, const Slice& value,
const Slice* const delta_value = nullptr);
// Finish building the block and return a slice that refers to the
// block contents. The returned slice will remain valid for the
// lifetime of this builder or until Reset() is called.
Slice Finish();
// Returns an estimate of the current (uncompressed) size of the block
// we are building.
inline size_t CurrentSizeEstimate() const {
return estimate_ + (data_block_hash_index_builder_.Valid()
? data_block_hash_index_builder_.EstimateSize()
: 0);
}
// Returns an estimated block size after appending key and value.
size_t EstimateSizeAfterKV(const Slice& key, const Slice& value) const;
// Return true iff no entries have been added since the last Reset()
bool empty() const { return buffer_.empty(); }
private:
const int block_restart_interval_;
// TODO(myabandeh): put it into a separate IndexBlockBuilder
const bool use_delta_encoding_;
// Refer to BlockIter::DecodeCurrentValue for format of delta encoded values
const bool use_value_delta_encoding_;
std::string buffer_; // Destination buffer
std::vector<uint32_t> restarts_; // Restart points
size_t estimate_;
int counter_; // Number of entries emitted since restart
bool finished_; // Has Finish() been called?
std::string last_key_;
DataBlockHashIndexBuilder data_block_hash_index_builder_;
};
} // namespace ROCKSDB_NAMESPACE