5009b5326b
Summary: Currently, if users define both of full key bloom and prefix bloom in SST files. During Get(), if full key bloom shows the key may exist, we still go ahead and check prefix bloom. This is wasteful. If bloom filter for full keys exists, we should always ignore prefix bloom in Get(). Test Plan: Run existing tests Reviewers: yhchiang, IslamAbdelRahman Reviewed By: IslamAbdelRahman Subscribers: leveldb, andrewkr, dhruba Differential Revision: https://reviews.facebook.net/D57825
113 lines
4.1 KiB
C++
113 lines
4.1 KiB
C++
// Copyright (c) 2011-present, 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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#pragma once
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#include <stddef.h>
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#include <stdint.h>
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#include <memory>
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#include <string>
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#include <vector>
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#include "rocksdb/options.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/slice_transform.h"
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#include "db/dbformat.h"
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#include "util/hash.h"
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#include "table/filter_block.h"
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namespace rocksdb {
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class FilterPolicy;
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class FilterBitsBuilder;
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class FilterBitsReader;
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// A FullFilterBlockBuilder is used to construct a full filter for a
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// particular Table. It generates a single string which is stored as
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// a special block in the Table.
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// The format of full filter block is:
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// +----------------------------------------------------------------+
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// | full filter for all keys in sst file |
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// +----------------------------------------------------------------+
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// The full filter can be very large. At the end of it, we put
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// num_probes: how many hash functions are used in bloom filter
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//
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class FullFilterBlockBuilder : public FilterBlockBuilder {
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public:
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explicit FullFilterBlockBuilder(const SliceTransform* prefix_extractor,
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bool whole_key_filtering,
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FilterBitsBuilder* filter_bits_builder);
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// bits_builder is created in filter_policy, it should be passed in here
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// directly. and be deleted here
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~FullFilterBlockBuilder() {}
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virtual bool IsBlockBased() override { return false; }
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virtual void StartBlock(uint64_t block_offset) override {}
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virtual void Add(const Slice& key) override;
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virtual Slice Finish() override;
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private:
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// important: all of these might point to invalid addresses
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// at the time of destruction of this filter block. destructor
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// should NOT dereference them.
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const SliceTransform* prefix_extractor_;
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bool whole_key_filtering_;
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uint32_t num_added_;
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std::unique_ptr<FilterBitsBuilder> filter_bits_builder_;
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std::unique_ptr<const char[]> filter_data_;
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void AddKey(const Slice& key);
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void AddPrefix(const Slice& key);
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// No copying allowed
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FullFilterBlockBuilder(const FullFilterBlockBuilder&);
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void operator=(const FullFilterBlockBuilder&);
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};
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// A FilterBlockReader is used to parse filter from SST table.
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// KeyMayMatch and PrefixMayMatch would trigger filter checking
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class FullFilterBlockReader : public FilterBlockReader {
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public:
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// REQUIRES: "contents" and filter_bits_reader must stay live
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// while *this is live.
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explicit FullFilterBlockReader(const SliceTransform* prefix_extractor,
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bool whole_key_filtering,
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const Slice& contents,
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FilterBitsReader* filter_bits_reader,
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Statistics* statistics);
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explicit FullFilterBlockReader(const SliceTransform* prefix_extractor,
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bool whole_key_filtering,
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BlockContents&& contents,
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FilterBitsReader* filter_bits_reader,
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Statistics* statistics);
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// bits_reader is created in filter_policy, it should be passed in here
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// directly. and be deleted here
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~FullFilterBlockReader() {}
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virtual bool IsBlockBased() override { return false; }
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virtual bool KeyMayMatch(const Slice& key,
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uint64_t block_offset = kNotValid) override;
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virtual bool PrefixMayMatch(const Slice& prefix,
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uint64_t block_offset = kNotValid) override;
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virtual size_t ApproximateMemoryUsage() const override;
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private:
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const SliceTransform* prefix_extractor_;
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std::unique_ptr<FilterBitsReader> filter_bits_reader_;
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Slice contents_;
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BlockContents block_contents_;
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std::unique_ptr<const char[]> filter_data_;
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bool MayMatch(const Slice& entry);
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// No copying allowed
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FullFilterBlockReader(const FullFilterBlockReader&);
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void operator=(const FullFilterBlockReader&);
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};
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} // namespace rocksdb
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