rocksdb/include/rocksdb/flush_block_policy.h
Dhruba Borthakur 31295b0a1b Add License message to public header files.
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Add License message to public header files.

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2013-11-18 10:21:35 -08:00

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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
#pragma once
#include <string>
namespace rocksdb {
class Slice;
class BlockBuilder;
// FlushBlockPolicy provides a configurable way to determine when to flush a
// block in the block based tables,
class FlushBlockPolicy {
public:
// Keep track of the key/value sequences and return the boolean value to
// determine if table builder should flush current data block.
virtual bool Update(const Slice& key,
const Slice& value) = 0;
virtual ~FlushBlockPolicy() { }
};
class FlushBlockPolicyFactory {
public:
// Return the name of the flush block policy.
virtual const char* Name() const = 0;
// Return a new block flush policy that flushes data blocks by data size.
// FlushBlockPolicy may need to access the metadata of the data block
// builder to determine when to flush the blocks.
//
// Callers must delete the result after any database that is using the
// result has been closed.
virtual FlushBlockPolicy* NewFlushBlockPolicy(
const BlockBuilder& data_block_builder) const = 0;
virtual ~FlushBlockPolicyFactory() { }
};
class FlushBlockBySizePolicyFactory : public FlushBlockPolicyFactory {
public:
FlushBlockBySizePolicyFactory(const uint64_t block_size,
const uint64_t block_size_deviation) :
block_size_(block_size),
block_size_deviation_(block_size_deviation) {
}
virtual const char* Name() const override {
return "FlushBlockBySizePolicyFactory";
}
virtual FlushBlockPolicy* NewFlushBlockPolicy(
const BlockBuilder& data_block_builder) const override;
private:
const uint64_t block_size_;
const uint64_t block_size_deviation_;
};
} // rocksdb