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
  11 #include <memory>
  12 #include <string>
  13 #include <vector>
  14
  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/filter_policy_internal.h"
  20 #include "table/block_based/parsed_full_filter_block.h"
  21 #include "util/hash.h"
  22
  23 namespace ROCKSDB_NAMESPACE {
  24
  25 class FilterPolicy;
  26 class FilterBitsBuilder;
  27 class FilterBitsReader;
  28
  29 // A FullFilterBlockBuilder is used to construct a full filter for a
  30 // particular Table.  It generates a single string which is stored as
  31 // a special block in the Table.
  32 // The format of full filter block is:
  33 // +----------------------------------------------------------------+
  34 // |              full filter for all keys in sst file              |
  35 // +----------------------------------------------------------------+
  36 // The full filter can be very large. At the end of it, we put
  37 // num_probes: how many hash functions are used in bloom filter
  38 //
  39 class FullFilterBlockBuilder : public FilterBlockBuilder {
  40  public:
  41   explicit FullFilterBlockBuilder(const SliceTransform* prefix_extractor,
  42                                   bool whole_key_filtering,
  43                                   FilterBitsBuilder* filter_bits_builder);
  44   // No copying allowed
  45   FullFilterBlockBuilder(const FullFilterBlockBuilder&) = delete;
  46   void operator=(const FullFilterBlockBuilder&) = delete;
  47
  48   // bits_builder is created in filter_policy, it should be passed in here
  49   // directly. and be deleted here
  50   ~FullFilterBlockBuilder() {}
  51
  52   virtual void Add(const Slice& key_without_ts) override;
  53   virtual bool IsEmpty() const override { return !any_added_; }
  54   virtual size_t EstimateEntriesAdded() override;
  55   virtual Slice Finish(
  56       const BlockHandle& tmp, Status* status,
  57       std::unique_ptr<const char[]>* filter_data = nullptr) override;
  58   using FilterBlockBuilder::Finish;
  59
  60   virtual void ResetFilterBitsBuilder() override {
  61     filter_bits_builder_.reset();
  62   }
  63
  64   virtual Status MaybePostVerifyFilter(const Slice& filter_content) override {
  65     return filter_bits_builder_->MaybePostVerify(filter_content);
  66   }
  67
  68  protected:
  69   virtual void AddKey(const Slice& key);
  70   std::unique_ptr<FilterBitsBuilder> filter_bits_builder_;
  71   virtual void Reset();
  72   void AddPrefix(const Slice& key);
  73   const SliceTransform* prefix_extractor() { return prefix_extractor_; }
  74   const std::string& last_prefix_str() const { return last_prefix_str_; }
  75
  76  private:
  77   // important: all of these might point to invalid addresses
  78   // at the time of destruction of this filter block. destructor
  79   // should NOT dereference them.
  80   const SliceTransform* prefix_extractor_;
  81   bool whole_key_filtering_;
  82   bool last_whole_key_recorded_;
  83   std::string last_whole_key_str_;
  84   bool last_prefix_recorded_;
  85   std::string last_prefix_str_;
  86   // Whether prefix_extractor_->InDomain(last_whole_key_) is true.
  87   // Used in partitioned filters so that the last prefix from the previous
  88   // filter partition will be added to the current partition if
  89   // last_key_in_domain_ is true, regardless of the current key.
  90   bool last_key_in_domain_;
  91   bool any_added_;
  92   std::unique_ptr<const char[]> filter_data_;
  93 };
  94
  95 // A FilterBlockReader is used to parse filter from SST table.
  96 // KeyMayMatch and PrefixMayMatch would trigger filter checking
  97 class FullFilterBlockReader
  98     : public FilterBlockReaderCommon<ParsedFullFilterBlock> {
  99  public:
 100   FullFilterBlockReader(const BlockBasedTable* t,
 101                         CachableEntry<ParsedFullFilterBlock>&& filter_block);
 102
 103   static std::unique_ptr<FilterBlockReader> Create(
 104       const BlockBasedTable* table, const ReadOptions& ro,
 105       FilePrefetchBuffer* prefetch_buffer, bool use_cache, bool prefetch,
 106       bool pin, BlockCacheLookupContext* lookup_context);
 107
 108   bool KeyMayMatch(const Slice& key, const bool no_io,
 109                    const Slice* const const_ikey_ptr, GetContext* get_context,
 110                    BlockCacheLookupContext* lookup_context,
 111                    Env::IOPriority rate_limiter_priority) override;
 112
 113   bool PrefixMayMatch(const Slice& prefix, const bool no_io,
 114                       const Slice* const const_ikey_ptr,
 115                       GetContext* get_context,
 116                       BlockCacheLookupContext* lookup_context,
 117                       Env::IOPriority rate_limiter_priority) override;
 118
 119   void KeysMayMatch(MultiGetRange* range, const bool no_io,
 120                     BlockCacheLookupContext* lookup_context,
 121                     Env::IOPriority rate_limiter_priority) override;
 122   // Used in partitioned filter code
 123   void KeysMayMatch2(MultiGetRange* range,
 124                      const SliceTransform* /*prefix_extractor*/,
 125                      const bool no_io, BlockCacheLookupContext* lookup_context,
 126                      Env::IOPriority rate_limiter_priority) {
 127     KeysMayMatch(range, no_io, lookup_context, rate_limiter_priority);
 128   }
 129
 130   void PrefixesMayMatch(MultiGetRange* range,
 131                         const SliceTransform* prefix_extractor,
 132                         const bool no_io,
 133                         BlockCacheLookupContext* lookup_context,
 134                         Env::IOPriority rate_limiter_priority) override;
 135   size_t ApproximateMemoryUsage() const override;
 136
 137  private:
 138   bool MayMatch(const Slice& entry, bool no_io, GetContext* get_context,
 139                 BlockCacheLookupContext* lookup_context,
 140                 Env::IOPriority rate_limiter_priority) const;
 141   void MayMatch(MultiGetRange* range, bool no_io,
 142                 const SliceTransform* prefix_extractor,
 143                 BlockCacheLookupContext* lookup_context,
 144                 Env::IOPriority rate_limiter_priority) const;
 145 };
 146
 147 }  // namespace ROCKSDB_NAMESPACE