ceph/src/rocksdb/include/rocksdb/flush_block_policy.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 <string>
   9 #include "rocksdb/table.h"
  10
  11 namespace rocksdb {
  12
  13 class Slice;
  14 class BlockBuilder;
  15 struct Options;
  16
  17 // FlushBlockPolicy provides a configurable way to determine when to flush a
  18 // block in the block based tables,
  19 class FlushBlockPolicy {
  20  public:
  21   // Keep track of the key/value sequences and return the boolean value to
  22   // determine if table builder should flush current data block.
  23   virtual bool Update(const Slice& key, const Slice& value) = 0;
  24
  25   virtual ~FlushBlockPolicy() {}
  26 };
  27
  28 class FlushBlockPolicyFactory {
  29  public:
  30   // Return the name of the flush block policy.
  31   virtual const char* Name() const = 0;
  32
  33   // Return a new block flush policy that flushes data blocks by data size.
  34   // FlushBlockPolicy may need to access the metadata of the data block
  35   // builder to determine when to flush the blocks.
  36   //
  37   // Callers must delete the result after any database that is using the
  38   // result has been closed.
  39   virtual FlushBlockPolicy* NewFlushBlockPolicy(
  40       const BlockBasedTableOptions& table_options,
  41       const BlockBuilder& data_block_builder) const = 0;
  42
  43   virtual ~FlushBlockPolicyFactory() {}
  44 };
  45
  46 class FlushBlockBySizePolicyFactory : public FlushBlockPolicyFactory {
  47  public:
  48   FlushBlockBySizePolicyFactory() {}
  49
  50   const char* Name() const override { return "FlushBlockBySizePolicyFactory"; }
  51
  52   FlushBlockPolicy* NewFlushBlockPolicy(
  53       const BlockBasedTableOptions& table_options,
  54       const BlockBuilder& data_block_builder) const override;
  55
  56   static FlushBlockPolicy* NewFlushBlockPolicy(
  57       const uint64_t size, const int deviation,
  58       const BlockBuilder& data_block_builder);
  59 };
  60
  61 }  // namespace rocksdb