82afa01815
Summary: * Clarify that RocksDB is not exception safe on many of our callback and extension interfaces * Clarify FSRandomAccessFile::MultiRead implementations must accept non-sorted inputs (see https://github.com/facebook/rocksdb/issues/8953) * Clarify ConcurrentTaskLimiter and SstFileManager are not (currently) extensible interfaces * Mark WriteBufferManager as `final`, so it is then clearly not a callback interface, even though it smells like one * Clarify TablePropertiesCollector Status returns are mostly ignored Pull Request resolved: https://github.com/facebook/rocksdb/pull/9080 Test Plan: comments only (except WriteBufferManager final) Reviewed By: ajkr Differential Revision: D31968782 Pulled By: pdillinger fbshipit-source-id: 11b648ce3ce3c5e5bdc02d2eafc7ea4b864bd1d2
76 lines
2.6 KiB
C++
76 lines
2.6 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#pragma once
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#include <string>
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#include "rocksdb/customizable.h"
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#include "rocksdb/table.h"
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namespace ROCKSDB_NAMESPACE {
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class Slice;
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class BlockBuilder;
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struct ConfigOptions;
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struct Options;
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// FlushBlockPolicy provides a configurable way to determine when to flush a
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// block in the block based tables.
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//
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// Exceptions MUST NOT propagate out of overridden functions into RocksDB,
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// because RocksDB is not exception-safe. This could cause undefined behavior
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// including data loss, unreported corruption, deadlocks, and more.
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class FlushBlockPolicy {
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public:
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// Keep track of the key/value sequences and return the boolean value to
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// determine if table builder should flush current data block.
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virtual bool Update(const Slice& key, const Slice& value) = 0;
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virtual ~FlushBlockPolicy() {}
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};
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class FlushBlockPolicyFactory : public Customizable {
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public:
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static const char* Type() { return "FlushBlockPolicyFactory"; }
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// Creates a FlushBlockPolicyFactory based on the input value.
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// By default, this method can create EveryKey or BySize PolicyFactory,
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// which take now config_options.
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static Status CreateFromString(
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const ConfigOptions& config_options, const std::string& value,
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std::shared_ptr<FlushBlockPolicyFactory>* result);
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// Return a new block flush policy that flushes data blocks by data size.
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// FlushBlockPolicy may need to access the metadata of the data block
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// builder to determine when to flush the blocks.
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//
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// Callers must delete the result after any database that is using the
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// result has been closed.
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virtual FlushBlockPolicy* NewFlushBlockPolicy(
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const BlockBasedTableOptions& table_options,
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const BlockBuilder& data_block_builder) const = 0;
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virtual ~FlushBlockPolicyFactory() {}
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};
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class FlushBlockBySizePolicyFactory : public FlushBlockPolicyFactory {
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public:
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FlushBlockBySizePolicyFactory();
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static const char* kClassName() { return "FlushBlockBySizePolicyFactory"; }
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const char* Name() const override { return kClassName(); }
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FlushBlockPolicy* NewFlushBlockPolicy(
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const BlockBasedTableOptions& table_options,
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const BlockBuilder& data_block_builder) const override;
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static FlushBlockPolicy* NewFlushBlockPolicy(
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const uint64_t size, const int deviation,
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const BlockBuilder& data_block_builder);
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};
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} // namespace ROCKSDB_NAMESPACE
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