df9069d23f
Summary: In this patch, try to allocate the whole iterator tree starting from DBIter from an arena 1. ArenaWrappedDBIter is created when serves as the entry point of an iterator tree, with an arena in it. 2. Add an option to create iterator from arena for following iterators: DBIter, MergingIterator, MemtableIterator, all mem table's iterators, all table reader's iterators and two level iterator. 3. MergeIteratorBuilder is created to incrementally build the tree of internal iterators. It is passed to mem table list and version set and add iterators to it. Limitations: (1) Only DB::NewIterator() without tailing uses the arena. Other cases, including readonly DB and compactions are still from malloc (2) Two level iterator itself is allocated in arena, but not iterators inside it. Test Plan: make all check Reviewers: ljin, haobo Reviewed By: haobo Subscribers: leveldb, dhruba, yhchiang, igor Differential Revision: https://reviews.facebook.net/D18513
96 lines
3.9 KiB
C++
96 lines
3.9 KiB
C++
// Copyright (c) 2013, 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 <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 "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 FileMetaData;
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// TODO(sdong): try to come up with a better API to pass the file information
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// other than simply passing FileMetaData.
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class TableCache {
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public:
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TableCache(const std::string& dbname, const Options* options,
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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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Iterator* NewIterator(const ReadOptions& options, const EnvOptions& toptions,
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const InternalKeyComparator& internal_comparator,
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const FileMetaData& file_meta,
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TableReader** table_reader_ptr = nullptr,
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bool for_compaction = false, Arena* arena = nullptr);
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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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Status Get(const ReadOptions& options,
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const InternalKeyComparator& internal_comparator,
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const FileMetaData& file_meta, const Slice& k, void* arg,
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bool (*handle_result)(void*, const ParsedInternalKey&,
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const Slice&, bool),
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bool* table_io, void (*mark_key_may_exist)(void*) = nullptr);
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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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// Find table reader
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Status FindTable(const EnvOptions& toptions,
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const InternalKeyComparator& internal_comparator,
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uint64_t file_number, uint64_t file_size, Cache::Handle**,
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bool* table_io = nullptr, const bool no_io = false);
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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 FileMetaData& file_meta,
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std::shared_ptr<const TableProperties>* properties,
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bool no_io = false);
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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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Env* const env_;
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const std::string dbname_;
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const Options* options_;
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const EnvOptions& storage_options_;
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Cache* const cache_;
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};
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} // namespace rocksdb
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