447f17127c
Summary: 1) The previous solution for Prev() prefix support is not clean. Since I add api SeekForPrev(), now the Prev() can be symmetric to Next(). and we do not need SeekToLast() to be called in Prev() any more. Also, Next() will Seek(prefix_seek_key_) to solve the problem of possible inconsistency between db_iter and merge_iter when there is merge_operator. And prefix_seek_key is only refreshed when change direction to forward. 2) This diff also solves the bug of Iterator::SeekToLast() with iterate_upper_bound_ with prefix extractor. add test cases for the above two cases. There are some tests for the SeekToLast() in Prev(), I will clean them later. Test Plan: make all check Reviewers: IslamAbdelRahman, andrewkr, yiwu, sdong Reviewed By: sdong Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D63933
86 lines
3.2 KiB
C++
86 lines
3.2 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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#pragma once
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#include <stdint.h>
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#include <string>
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#include "db/dbformat.h"
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#include "rocksdb/db.h"
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#include "rocksdb/iterator.h"
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#include "util/arena.h"
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#include "util/autovector.h"
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#include "util/cf_options.h"
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namespace rocksdb {
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class Arena;
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class DBIter;
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class InternalIterator;
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// Return a new iterator that converts internal keys (yielded by
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// "*internal_iter") that were live at the specified "sequence" number
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// into appropriate user keys.
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extern Iterator* NewDBIterator(
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Env* env, const ImmutableCFOptions& options,
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const Comparator* user_key_comparator, InternalIterator* internal_iter,
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const SequenceNumber& sequence, uint64_t max_sequential_skip_in_iterations,
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uint64_t version_number, const Slice* iterate_upper_bound = nullptr,
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bool prefix_same_as_start = false, bool pin_data = false,
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bool total_order_seek = false);
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// A wrapper iterator which wraps DB Iterator and the arena, with which the DB
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// iterator is supposed be allocated. This class is used as an entry point of
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// a iterator hierarchy whose memory can be allocated inline. In that way,
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// accessing the iterator tree can be more cache friendly. It is also faster
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// to allocate.
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class ArenaWrappedDBIter : public Iterator {
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public:
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virtual ~ArenaWrappedDBIter();
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// Get the arena to be used to allocate memory for DBIter to be wrapped,
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// as well as child iterators in it.
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virtual Arena* GetArena() { return &arena_; }
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// Set the DB Iterator to be wrapped
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virtual void SetDBIter(DBIter* iter);
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// Set the internal iterator wrapped inside the DB Iterator. Usually it is
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// a merging iterator.
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virtual void SetIterUnderDBIter(InternalIterator* iter);
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virtual bool Valid() const override;
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virtual void SeekToFirst() override;
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virtual void SeekToLast() override;
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virtual void Seek(const Slice& target) override;
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virtual void SeekForPrev(const Slice& target) override;
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virtual void Next() override;
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virtual void Prev() override;
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virtual Slice key() const override;
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virtual Slice value() const override;
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virtual Status status() const override;
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void RegisterCleanup(CleanupFunction function, void* arg1, void* arg2);
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virtual Status GetProperty(std::string prop_name, std::string* prop) override;
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private:
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DBIter* db_iter_;
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Arena arena_;
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};
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// Generate the arena wrapped iterator class.
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extern ArenaWrappedDBIter* NewArenaWrappedDbIterator(
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Env* env, const ImmutableCFOptions& options,
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const Comparator* user_key_comparator, const SequenceNumber& sequence,
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uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
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const Slice* iterate_upper_bound = nullptr,
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bool prefix_same_as_start = false, bool pin_data = false,
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bool total_order_seek = false);
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} // namespace rocksdb
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