aececc209e
Summary: This patch update the Iterator API to introduce new functions that allow users to keep the Slices returned by key() valid as long as the Iterator is not deleted ReadOptions::pin_data : If true keep loaded blocks in memory as long as the iterator is not deleted Iterator::IsKeyPinned() : If true, this mean that the Slice returned by key() is valid as long as the iterator is not deleted Also add a new option BlockBasedTableOptions::use_delta_encoding to allow users to disable delta_encoding if needed. Benchmark results (using https://phabricator.fb.com/P20083553) ``` // $ du -h /home/tec/local/normal.4K.Snappy/db10077 // 6.1G /home/tec/local/normal.4K.Snappy/db10077 // $ du -h /home/tec/local/zero.8K.LZ4/db10077 // 6.4G /home/tec/local/zero.8K.LZ4/db10077 // Benchmarks for shard db10077 // _build/opt/rocks/benchmark/rocks_copy_benchmark \ // --normal_db_path="/home/tec/local/normal.4K.Snappy/db10077" \ // --zero_db_path="/home/tec/local/zero.8K.LZ4/db10077" // First run // ============================================================================ // rocks/benchmark/RocksCopyBenchmark.cpp relative time/iter iters/s // ============================================================================ // BM_StringCopy 1.73s 576.97m // BM_StringPiece 103.74% 1.67s 598.55m // ============================================================================ // Match rate : 1000000 / 1000000 // Second run // ============================================================================ // rocks/benchmark/RocksCopyBenchmark.cpp relative time/iter iters/s // ============================================================================ // BM_StringCopy 611.99ms 1.63 // BM_StringPiece 203.76% 300.35ms 3.33 // ============================================================================ // Match rate : 1000000 / 1000000 ``` Test Plan: Unit tests Reviewers: sdong, igor, anthony, yhchiang, rven Reviewed By: rven Subscribers: dhruba, lovro, adsharma Differential Revision: https://reviews.facebook.net/D48999
62 lines
2.1 KiB
C++
62 lines
2.1 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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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 <vector>
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#include <stdint.h>
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#include "rocksdb/slice.h"
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namespace rocksdb {
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class BlockBuilder {
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public:
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BlockBuilder(const BlockBuilder&) = delete;
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void operator=(const BlockBuilder&) = delete;
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explicit BlockBuilder(int block_restart_interval,
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bool use_delta_encoding = true);
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// Reset the contents as if the BlockBuilder was just constructed.
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void Reset();
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// REQUIRES: Finish() has not been callled since the last call to Reset().
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// REQUIRES: key is larger than any previously added key
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void Add(const Slice& key, const Slice& value);
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// Finish building the block and return a slice that refers to the
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// block contents. The returned slice will remain valid for the
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// lifetime of this builder or until Reset() is called.
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Slice Finish();
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// Returns an estimate of the current (uncompressed) size of the block
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// we are building.
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size_t CurrentSizeEstimate() const;
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// Returns an estimated block size after appending key and value.
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size_t EstimateSizeAfterKV(const Slice& key, const Slice& value) const;
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// Return true iff no entries have been added since the last Reset()
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bool empty() const {
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return buffer_.empty();
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}
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private:
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const int block_restart_interval_;
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const bool use_delta_encoding_;
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std::string buffer_; // Destination buffer
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std::vector<uint32_t> restarts_; // Restart points
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int counter_; // Number of entries emitted since restart
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bool finished_; // Has Finish() been called?
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std::string last_key_;
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};
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} // namespace rocksdb
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