Revision bd2c753dd0b48f83818042d1caae5e47fc6444aa authored by sdong on 15 August 2019, 23:59:42 UTC, committed by Facebook Github Bot on 16 August 2019, 00:01:03 UTC
Summary: Add a command in ldb so that users can print out tombstones in SST files. In order to test the code, change the interface of LDBCommandRunner::RunCommand() so that it doesn't return from the program, but return the status code. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5615 Test Plan: Add a new unit test Differential Revision: D16550326 fbshipit-source-id: 88ddfe6984bdcbb3a528abdd115089df09eba52e
1 parent 6ec2bf3
db_iter.h
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <stdint.h>
#include <string>
#include "db/db_impl/db_impl.h"
#include "db/dbformat.h"
#include "db/range_del_aggregator.h"
#include "memory/arena.h"
#include "options/cf_options.h"
#include "rocksdb/db.h"
#include "rocksdb/iterator.h"
#include "util/autovector.h"
namespace rocksdb {
// This file declares the factory functions of DBIter, in its original form
// or a wrapped form with class ArenaWrappedDBIter, which is defined here.
// Class DBIter, which is declared and implemented inside db_iter.cc, is
// a iterator that converts internal keys (yielded by an InternalIterator)
// that were live at the specified sequence number into appropriate user
// keys.
// Each internal key is consist of a user key, a sequence number, and a value
// type. DBIter deals with multiple key versions, tombstones, merge operands,
// etc, and exposes an Iterator.
// For example, DBIter may wrap following InternalIterator:
// user key: AAA value: v3 seqno: 100 type: Put
// user key: AAA value: v2 seqno: 97 type: Put
// user key: AAA value: v1 seqno: 95 type: Put
// user key: BBB value: v1 seqno: 90 type: Put
// user key: BBC value: N/A seqno: 98 type: Delete
// user key: BBC value: v1 seqno: 95 type: Put
// If the snapshot passed in is 102, then the DBIter is expected to
// expose the following iterator:
// key: AAA value: v3
// key: BBB value: v1
// If the snapshot passed in is 96, then it should expose:
// key: AAA value: v1
// key: BBB value: v1
// key: BBC value: v1
//
class Arena;
class DBIter;
// Return a new iterator that converts internal keys (yielded by
// "*internal_iter") that were live at the specified `sequence` number
// into appropriate user keys.
extern Iterator* NewDBIterator(
Env* env, const ReadOptions& read_options,
const ImmutableCFOptions& cf_options,
const MutableCFOptions& mutable_cf_options,
const Comparator* user_key_comparator, InternalIterator* internal_iter,
const SequenceNumber& sequence, uint64_t max_sequential_skip_in_iterations,
ReadCallback* read_callback, DBImpl* db_impl = nullptr,
ColumnFamilyData* cfd = nullptr, bool allow_blob = false);
// A wrapper iterator which wraps DB Iterator and the arena, with which the DB
// iterator is supposed be allocated. This class is used as an entry point of
// a iterator hierarchy whose memory can be allocated inline. In that way,
// accessing the iterator tree can be more cache friendly. It is also faster
// to allocate.
// When using the class's Iterator interface, the behavior is exactly
// the same as the inner DBIter.
class ArenaWrappedDBIter : public Iterator {
public:
virtual ~ArenaWrappedDBIter();
// Get the arena to be used to allocate memory for DBIter to be wrapped,
// as well as child iterators in it.
virtual Arena* GetArena() { return &arena_; }
virtual ReadRangeDelAggregator* GetRangeDelAggregator();
// Set the internal iterator wrapped inside the DB Iterator. Usually it is
// a merging iterator.
virtual void SetIterUnderDBIter(InternalIterator* iter);
virtual bool Valid() const override;
virtual void SeekToFirst() override;
virtual void SeekToLast() override;
virtual void Seek(const Slice& target) override;
virtual void SeekForPrev(const Slice& target) override;
virtual void Next() override;
virtual void Prev() override;
virtual Slice key() const override;
virtual Slice value() const override;
virtual Status status() const override;
virtual Status Refresh() override;
bool IsBlob() const;
virtual Status GetProperty(std::string prop_name, std::string* prop) override;
void Init(Env* env, const ReadOptions& read_options,
const ImmutableCFOptions& cf_options,
const MutableCFOptions& mutable_cf_options,
const SequenceNumber& sequence,
uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
ReadCallback* read_callback, DBImpl* db_impl, ColumnFamilyData* cfd,
bool allow_blob, bool allow_refresh);
void StoreRefreshInfo(const ReadOptions& read_options, DBImpl* db_impl,
ColumnFamilyData* cfd, ReadCallback* read_callback,
bool allow_blob) {
read_options_ = read_options;
db_impl_ = db_impl;
cfd_ = cfd;
read_callback_ = read_callback;
allow_blob_ = allow_blob;
}
private:
DBIter* db_iter_;
Arena arena_;
uint64_t sv_number_;
ColumnFamilyData* cfd_ = nullptr;
DBImpl* db_impl_ = nullptr;
ReadOptions read_options_;
ReadCallback* read_callback_;
bool allow_blob_ = false;
bool allow_refresh_ = true;
};
// Generate the arena wrapped iterator class.
// `db_impl` and `cfd` are used for reneweal. If left null, renewal will not
// be supported.
extern ArenaWrappedDBIter* NewArenaWrappedDbIterator(
Env* env, const ReadOptions& read_options,
const ImmutableCFOptions& cf_options,
const MutableCFOptions& mutable_cf_options, const SequenceNumber& sequence,
uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
ReadCallback* read_callback, DBImpl* db_impl = nullptr,
ColumnFamilyData* cfd = nullptr, bool allow_blob = false,
bool allow_refresh = true);
} // namespace rocksdb
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