ceph/src/rocksdb/table/block_based/full_filter_block.h

   1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5
   6 #pragma once
   7
   8 #include <stddef.h>
   9 #include <stdint.h>
  10 #include <memory>
  11 #include <string>
  12 #include <vector>
  13
  14 #include "db/dbformat.h"
  15 #include "rocksdb/options.h"
  16 #include "rocksdb/slice.h"
  17 #include "rocksdb/slice_transform.h"
  18 #include "table/block_based/filter_block_reader_common.h"
  19 #include "table/block_based/parsed_full_filter_block.h"
  20 #include "util/hash.h"
  21
  22 namespace ROCKSDB_NAMESPACE {
  23
  24 class FilterPolicy;
  25 class FilterBitsBuilder;
  26 class FilterBitsReader;
  27
  28 // A FullFilterBlockBuilder is used to construct a full filter for a
  29 // particular Table.  It generates a single string which is stored as
  30 // a special block in the Table.
  31 // The format of full filter block is:
  32 // +----------------------------------------------------------------+
  33 // |              full filter for all keys in sst file              |
  34 // +----------------------------------------------------------------+
  35 // The full filter can be very large. At the end of it, we put
  36 // num_probes: how many hash functions are used in bloom filter
  37 //
  38 class FullFilterBlockBuilder : public FilterBlockBuilder {
  39  public:
  40   explicit FullFilterBlockBuilder(const SliceTransform* prefix_extractor,
  41                                   bool whole_key_filtering,
  42                                   FilterBitsBuilder* filter_bits_builder);
  43   // No copying allowed
  44   FullFilterBlockBuilder(const FullFilterBlockBuilder&) = delete;
  45   void operator=(const FullFilterBlockBuilder&) = delete;
  46
  47   // bits_builder is created in filter_policy, it should be passed in here
  48   // directly. and be deleted here
  49   ~FullFilterBlockBuilder() {}
  50
  51   virtual bool IsBlockBased() override { return false; }
  52   virtual void StartBlock(uint64_t /*block_offset*/) override {}
  53   virtual void Add(const Slice& key) override;
  54   virtual size_t NumAdded() const override { return num_added_; }
  55   virtual Slice Finish(const BlockHandle& tmp, Status* status) override;
  56   using FilterBlockBuilder::Finish;
  57
  58  protected:
  59   virtual void AddKey(const Slice& key);
  60   std::unique_ptr<FilterBitsBuilder> filter_bits_builder_;
  61   virtual void Reset();
  62   void AddPrefix(const Slice& key);
  63   const SliceTransform* prefix_extractor() { return prefix_extractor_; }
  64
  65  private:
  66   // important: all of these might point to invalid addresses
  67   // at the time of destruction of this filter block. destructor
  68   // should NOT dereference them.
  69   const SliceTransform* prefix_extractor_;
  70   bool whole_key_filtering_;
  71   bool last_whole_key_recorded_;
  72   std::string last_whole_key_str_;
  73   bool last_prefix_recorded_;
  74   std::string last_prefix_str_;
  75
  76   uint32_t num_added_;
  77   std::unique_ptr<const char[]> filter_data_;
  78
  79 };
  80
  81 // A FilterBlockReader is used to parse filter from SST table.
  82 // KeyMayMatch and PrefixMayMatch would trigger filter checking
  83 class FullFilterBlockReader
  84     : public FilterBlockReaderCommon<ParsedFullFilterBlock> {
  85  public:
  86   FullFilterBlockReader(const BlockBasedTable* t,
  87                         CachableEntry<ParsedFullFilterBlock>&& filter_block);
  88
  89   static std::unique_ptr<FilterBlockReader> Create(
  90       const BlockBasedTable* table, const ReadOptions& ro,
  91       FilePrefetchBuffer* prefetch_buffer, bool use_cache, bool prefetch,
  92       bool pin, BlockCacheLookupContext* lookup_context);
  93
  94   bool IsBlockBased() override { return false; }
  95
  96   bool KeyMayMatch(const Slice& key, const SliceTransform* prefix_extractor,
  97                    uint64_t block_offset, const bool no_io,
  98                    const Slice* const const_ikey_ptr, GetContext* get_context,
  99                    BlockCacheLookupContext* lookup_context) override;
 100
 101   bool PrefixMayMatch(const Slice& prefix,
 102                       const SliceTransform* prefix_extractor,
 103                       uint64_t block_offset, const bool no_io,
 104                       const Slice* const const_ikey_ptr,
 105                       GetContext* get_context,
 106                       BlockCacheLookupContext* lookup_context) override;
 107
 108   void KeysMayMatch(MultiGetRange* range,
 109                     const SliceTransform* prefix_extractor,
 110                     uint64_t block_offset, const bool no_io,
 111                     BlockCacheLookupContext* lookup_context) override;
 112
 113   void PrefixesMayMatch(MultiGetRange* range,
 114                         const SliceTransform* prefix_extractor,
 115                         uint64_t block_offset, const bool no_io,
 116                         BlockCacheLookupContext* lookup_context) override;
 117   size_t ApproximateMemoryUsage() const override;
 118   bool RangeMayExist(const Slice* iterate_upper_bound, const Slice& user_key,
 119                      const SliceTransform* prefix_extractor,
 120                      const Comparator* comparator,
 121                      const Slice* const const_ikey_ptr, bool* filter_checked,
 122                      bool need_upper_bound_check, bool no_io,
 123                      BlockCacheLookupContext* lookup_context) override;
 124
 125  private:
 126   bool MayMatch(const Slice& entry, bool no_io, GetContext* get_context,
 127                 BlockCacheLookupContext* lookup_context) const;
 128   void MayMatch(MultiGetRange* range, bool no_io,
 129                 const SliceTransform* prefix_extractor,
 130                 BlockCacheLookupContext* lookup_context) const;
 131   bool IsFilterCompatible(const Slice* iterate_upper_bound, const Slice& prefix,
 132                           const Comparator* comparator) const;
 133
 134  private:
 135   bool full_length_enabled_;
 136   size_t prefix_extractor_full_length_;
 137 };
 138
 139 }  // namespace ROCKSDB_NAMESPACE