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rust-rocksdb/include/rocksdb/flush_block_policy.h

75 lines
2.6 KiB

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include <string>
#include "rocksdb/customizable.h"
#include "rocksdb/table.h"
namespace ROCKSDB_NAMESPACE {
class Slice;
class BlockBuilder;
struct ConfigOptions;
struct Options;
// FlushBlockPolicy provides a configurable way to determine when to flush a
// block in the block based tables.
//
// Exceptions MUST NOT propagate out of overridden functions into RocksDB,
// because RocksDB is not exception-safe. This could cause undefined behavior
// including data loss, unreported corruption, deadlocks, and more.
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 Customizable {
public:
static const char* Type() { return "FlushBlockPolicyFactory"; }
// Creates a FlushBlockPolicyFactory based on the input value.
// By default, this method can create EveryKey or BySize PolicyFactory,
// which take now config_options.
static Status CreateFromString(
const ConfigOptions& config_options, const std::string& value,
std::shared_ptr<FlushBlockPolicyFactory>* result);
// 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 BlockBasedTableOptions& table_options,
const BlockBuilder& data_block_builder) const = 0;
virtual ~FlushBlockPolicyFactory() {}
};
class FlushBlockBySizePolicyFactory : public FlushBlockPolicyFactory {
public:
FlushBlockBySizePolicyFactory();
static const char* kClassName() { return "FlushBlockBySizePolicyFactory"; }
const char* Name() const override { return kClassName(); }
FlushBlockPolicy* NewFlushBlockPolicy(
const BlockBasedTableOptions& table_options,
const BlockBuilder& data_block_builder) const override;
static FlushBlockPolicy* NewFlushBlockPolicy(
const uint64_t size, const int deviation,
const BlockBuilder& data_block_builder);
};
} // namespace ROCKSDB_NAMESPACE