055e6df45b
Summary: I will submit a sequence of diffs that are preparing master branch for column families. There are a lot of implicit assumptions in the code that are making column family implementation hard. If I make the change only in column family branch, it will make merging back to master impossible. Most of the diffs will be simple code refactorings, so I hope we can have fast turnaround time. Feel free to grab me in person to discuss any of them. This diff removes number of level check from VersionEdit. It is used only when VersionEdit is read, not written, but has to be set when it is written. I believe it is a right thing to make VersionEdit dumb and check consistency on the caller side. This will also make it much easier to implement Column Families, since different column families can have different number of levels. Test Plan: make check Reviewers: dhruba, haobo, sdong, kailiu Reviewed By: kailiu CC: leveldb Differential Revision: https://reviews.facebook.net/D15159
102 lines
2.9 KiB
C++
102 lines
2.9 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) 2012 Facebook. 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.
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#include "db/db_impl_readonly.h"
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#include "db/db_impl.h"
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#include <algorithm>
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#include <set>
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#include <string>
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#include <stdint.h>
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#include <stdio.h>
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#include <vector>
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#include <algorithm>
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#include "db/db_iter.h"
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#include "db/dbformat.h"
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#include "db/filename.h"
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#include "db/log_reader.h"
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#include "db/log_writer.h"
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#include "db/memtable.h"
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#include "db/merge_context.h"
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#include "db/table_cache.h"
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#include "db/version_set.h"
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#include "db/write_batch_internal.h"
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#include "rocksdb/db.h"
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#include "rocksdb/env.h"
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#include "rocksdb/status.h"
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#include "rocksdb/table.h"
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#include "rocksdb/merge_operator.h"
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#include "port/port.h"
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#include "table/block.h"
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#include "table/merger.h"
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#include "table/two_level_iterator.h"
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#include "util/coding.h"
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#include "util/logging.h"
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#include "util/build_version.h"
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namespace rocksdb {
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DBImplReadOnly::DBImplReadOnly(const Options& options,
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const std::string& dbname)
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: DBImpl(options, dbname) {
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Log(options_.info_log, "Opening the db in read only mode");
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}
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DBImplReadOnly::~DBImplReadOnly() {
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}
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// Implementations of the DB interface
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Status DBImplReadOnly::Get(const ReadOptions& options,
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const Slice& key,
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std::string* value) {
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Status s;
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MemTable* mem = GetMemTable();
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Version* current = versions_->current();
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SequenceNumber snapshot = versions_->LastSequence();
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MergeContext merge_context;
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LookupKey lkey(key, snapshot);
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if (mem->Get(lkey, value, &s, merge_context, options_)) {
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} else {
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Version::GetStats stats;
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current->Get(options, lkey, value, &s, &merge_context, &stats, options_);
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}
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return s;
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}
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Iterator* DBImplReadOnly::NewIterator(const ReadOptions& options) {
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SequenceNumber latest_snapshot;
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Iterator* internal_iter = NewInternalIterator(options, &latest_snapshot);
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return NewDBIterator(
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&dbname_, env_, options_, user_comparator(),internal_iter,
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(options.snapshot != nullptr
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? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
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: latest_snapshot));
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}
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Status DB::OpenForReadOnly(const Options& options, const std::string& dbname,
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DB** dbptr, bool error_if_log_file_exist) {
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*dbptr = nullptr;
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DBImplReadOnly* impl = new DBImplReadOnly(options, dbname);
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impl->mutex_.Lock();
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VersionEdit edit;
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Status s = impl->Recover(&edit, impl->GetMemTable(),
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error_if_log_file_exist);
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impl->mutex_.Unlock();
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if (s.ok()) {
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*dbptr = impl;
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} else {
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delete impl;
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}
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return s;
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}
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}
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