ceph/src/rocksdb/utilities/table_properties_collectors/compact_on_deletion_collector.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 #ifndef ROCKSDB_LITE
   9 #include "rocksdb/utilities/table_properties_collectors.h"
  10 namespace ROCKSDB_NAMESPACE {
  11
  12 class CompactOnDeletionCollector : public TablePropertiesCollector {
  13  public:
  14   CompactOnDeletionCollector(size_t sliding_window_size,
  15                              size_t deletion_trigger, double deletion_raatio);
  16
  17   // AddUserKey() will be called when a new key/value pair is inserted into the
  18   // table.
  19   // @params key    the user key that is inserted into the table.
  20   // @params value  the value that is inserted into the table.
  21   // @params file_size  file size up to now
  22   virtual Status AddUserKey(const Slice& key, const Slice& value,
  23                             EntryType type, SequenceNumber seq,
  24                             uint64_t file_size) override;
  25
  26   // Finish() will be called when a table has already been built and is ready
  27   // for writing the properties block.
  28   // @params properties  User will add their collected statistics to
  29   // `properties`.
  30   virtual Status Finish(UserCollectedProperties* /*properties*/) override;
  31
  32   // Return the human-readable properties, where the key is property name and
  33   // the value is the human-readable form of value.
  34   virtual UserCollectedProperties GetReadableProperties() const override {
  35     return UserCollectedProperties();
  36   }
  37
  38   // The name of the properties collector can be used for debugging purpose.
  39   virtual const char* Name() const override {
  40     return "CompactOnDeletionCollector";
  41   }
  42
  43   // EXPERIMENTAL Return whether the output file should be further compacted
  44   virtual bool NeedCompact() const override {
  45     return need_compaction_;
  46   }
  47
  48   static const int kNumBuckets = 128;
  49
  50  private:
  51   void Reset();
  52
  53   // A ring buffer that used to count the number of deletion entries for every
  54   // "bucket_size_" keys.
  55   size_t num_deletions_in_buckets_[kNumBuckets];
  56   // the number of keys in a bucket
  57   size_t bucket_size_;
  58
  59   size_t current_bucket_;
  60   size_t num_keys_in_current_bucket_;
  61   size_t num_deletions_in_observation_window_;
  62   size_t deletion_trigger_;
  63   const double deletion_ratio_;
  64   const bool deletion_ratio_enabled_;
  65   size_t total_entries_ = 0;
  66   size_t deletion_entries_ = 0;
  67   // true if the current SST file needs to be compacted.
  68   bool need_compaction_;
  69   bool finished_;
  70 };
  71 }  // namespace ROCKSDB_NAMESPACE
  72 #endif  // !ROCKSDB_LITE