2182bf2828
Summary: Add an option `iterator_readahead_size` to `ReadOptions` to enable configurable readahead for iterators similar to the corresponding option for compaction. Test Plan: ``` make commit_prereq ``` Reviewers: kumar.rangarajan, ott, igor, sdong Reviewed By: sdong Subscribers: yiwu, andrewkr, dhruba Differential Revision: https://reviews.facebook.net/D55419
126 lines
5.2 KiB
C++
126 lines
5.2 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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//
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// Thread-safe (provides internal synchronization)
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#pragma once
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#include <string>
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#include <vector>
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#include <stdint.h>
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#include "db/dbformat.h"
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#include "port/port.h"
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#include "rocksdb/cache.h"
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#include "rocksdb/env.h"
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#include "rocksdb/table.h"
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#include "rocksdb/options.h"
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#include "table/table_reader.h"
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namespace rocksdb {
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class Env;
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class Arena;
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struct FileDescriptor;
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class GetContext;
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class HistogramImpl;
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class InternalIterator;
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class TableCache {
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public:
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TableCache(const ImmutableCFOptions& ioptions,
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const EnvOptions& storage_options, Cache* cache);
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~TableCache();
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// Return an iterator for the specified file number (the corresponding
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// file length must be exactly "file_size" bytes). If "tableptr" is
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// non-nullptr, also sets "*tableptr" to point to the Table object
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// underlying the returned iterator, or nullptr if no Table object underlies
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// the returned iterator. The returned "*tableptr" object is owned by
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// the cache and should not be deleted, and is valid for as long as the
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// returned iterator is live.
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// @param skip_filters Disables loading/accessing the filter block
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// @param level The level this table is at, -1 for "not set / don't know"
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InternalIterator* NewIterator(
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const ReadOptions& options, const EnvOptions& toptions,
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const InternalKeyComparator& internal_comparator,
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const FileDescriptor& file_fd, TableReader** table_reader_ptr = nullptr,
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HistogramImpl* file_read_hist = nullptr, bool for_compaction = false,
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Arena* arena = nullptr, bool skip_filters = false, int level = -1);
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// If a seek to internal key "k" in specified file finds an entry,
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// call (*handle_result)(arg, found_key, found_value) repeatedly until
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// it returns false.
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// @param skip_filters Disables loading/accessing the filter block
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// @param level The level this table is at, -1 for "not set / don't know"
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Status Get(const ReadOptions& options,
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const InternalKeyComparator& internal_comparator,
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const FileDescriptor& file_fd, const Slice& k,
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GetContext* get_context, HistogramImpl* file_read_hist = nullptr,
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bool skip_filters = false, int level = -1);
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// Evict any entry for the specified file number
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static void Evict(Cache* cache, uint64_t file_number);
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// Clean table handle and erase it from the table cache
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// Used in DB close, or the file is not live anymore.
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void EraseHandle(const FileDescriptor& fd, Cache::Handle* handle);
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// Find table reader
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// @param skip_filters Disables loading/accessing the filter block
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// @param level == -1 means not specified
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Status FindTable(const EnvOptions& toptions,
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const InternalKeyComparator& internal_comparator,
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const FileDescriptor& file_fd, Cache::Handle**,
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const bool no_io = false, bool record_read_stats = true,
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HistogramImpl* file_read_hist = nullptr,
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bool skip_filters = false, int level = -1);
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// Get TableReader from a cache handle.
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TableReader* GetTableReaderFromHandle(Cache::Handle* handle);
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// Get the table properties of a given table.
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// @no_io: indicates if we should load table to the cache if it is not present
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// in table cache yet.
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// @returns: `properties` will be reset on success. Please note that we will
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// return Status::Incomplete() if table is not present in cache and
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// we set `no_io` to be true.
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Status GetTableProperties(const EnvOptions& toptions,
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const InternalKeyComparator& internal_comparator,
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const FileDescriptor& file_meta,
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std::shared_ptr<const TableProperties>* properties,
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bool no_io = false);
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// Return total memory usage of the table reader of the file.
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// 0 if table reader of the file is not loaded.
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size_t GetMemoryUsageByTableReader(
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const EnvOptions& toptions,
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const InternalKeyComparator& internal_comparator,
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const FileDescriptor& fd);
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// Release the handle from a cache
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void ReleaseHandle(Cache::Handle* handle);
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private:
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// Build a table reader
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Status GetTableReader(const EnvOptions& env_options,
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const InternalKeyComparator& internal_comparator,
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const FileDescriptor& fd, bool sequential_mode,
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size_t readahead, bool record_read_stats,
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HistogramImpl* file_read_hist,
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unique_ptr<TableReader>* table_reader,
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bool skip_filters = false, int level = -1);
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const ImmutableCFOptions& ioptions_;
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const EnvOptions& env_options_;
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Cache* const cache_;
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std::string row_cache_id_;
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};
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} // namespace rocksdb
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