e67b35c076
Summary: Add and implement Iterator::Refresh(). When this function is called, if the super version doesn't change, update the sequence number of the iterator to the latest one and invalidate the iterator. If the super version changed, recreated the whole iterator. This can help users reuse the iterator more easily. Closes https://github.com/facebook/rocksdb/pull/2621 Differential Revision: D5464500 Pulled By: siying fbshipit-source-id: f548bd35e85c1efca2ea69273802f6704eba6ba9
101 lines
3.7 KiB
C++
101 lines
3.7 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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//
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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/db_impl.h"
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#include "db/dbformat.h"
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#include "db/range_del_aggregator.h"
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#include "options/cf_options.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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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(Env* env, const ReadOptions& read_options,
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const ImmutableCFOptions& cf_options,
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const Comparator* user_key_comparator,
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InternalIterator* internal_iter,
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const SequenceNumber& sequence,
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uint64_t max_sequential_skip_in_iterations);
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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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virtual RangeDelAggregator* GetRangeDelAggregator();
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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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virtual Status Refresh() override;
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virtual Status GetProperty(std::string prop_name, std::string* prop) override;
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void Init(Env* env, const ReadOptions& read_options,
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const ImmutableCFOptions& cf_options,
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const SequenceNumber& sequence,
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uint64_t max_sequential_skip_in_iterations,
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uint64_t version_number);
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void StoreRefreshInfo(const ReadOptions& read_options, DBImpl* db_impl,
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ColumnFamilyData* cfd) {
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read_options_ = read_options;
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db_impl_ = db_impl;
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cfd_ = cfd;
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}
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private:
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DBIter* db_iter_;
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Arena arena_;
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uint64_t sv_number_;
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ColumnFamilyData* cfd_ = nullptr;
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DBImpl* db_impl_ = nullptr;
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ReadOptions read_options_;
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};
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// Generate the arena wrapped iterator class.
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// `db_impl` and `cfd` are used for reneweal. If left null, renewal will not
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// be supported.
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extern ArenaWrappedDBIter* NewArenaWrappedDbIterator(
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Env* env, const ReadOptions& read_options,
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const ImmutableCFOptions& cf_options, const SequenceNumber& sequence,
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uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
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DBImpl* db_impl = nullptr, ColumnFamilyData* cfd = nullptr);
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} // namespace rocksdb
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