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rocksdb/db/db_impl_readonly.cc

118 lines
3.9 KiB

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2012 Facebook. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "db/db_impl_readonly.h"
#include "db/db_impl.h"
#include <algorithm>
#include <set>
#include <string>
#include <stdint.h>
#include <stdio.h>
#include <vector>
#include <algorithm>
#include "db/db_iter.h"
#include "db/dbformat.h"
#include "db/filename.h"
#include "db/log_reader.h"
#include "db/log_writer.h"
#include "db/memtable.h"
#include "db/merge_context.h"
#include "db/table_cache.h"
#include "db/version_set.h"
#include "db/write_batch_internal.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/column_family.h"
#include "rocksdb/status.h"
#include "rocksdb/table.h"
#include "rocksdb/merge_operator.h"
#include "port/port.h"
#include "table/block.h"
#include "table/merger.h"
#include "table/two_level_iterator.h"
#include "util/coding.h"
#include "util/logging.h"
#include "util/build_version.h"
namespace rocksdb {
DBImplReadOnly::DBImplReadOnly(const DBOptions& options,
const std::string& dbname)
: DBImpl(options, dbname) {
Log(options_.info_log, "Opening the db in read only mode");
}
DBImplReadOnly::~DBImplReadOnly() {
}
// Implementations of the DB interface
Status DBImplReadOnly::Get(const ReadOptions& options,
const ColumnFamilyHandle& column_family,
const Slice& key, std::string* value) {
Status s;
SequenceNumber snapshot = versions_->LastSequence();
auto cfd = versions_->GetColumnFamilySet()->GetColumnFamily(column_family.id);
SuperVersion* super_version = cfd->GetSuperVersion();
MergeContext merge_context;
LookupKey lkey(key, snapshot);
if (super_version->mem->Get(lkey, value, &s, merge_context,
*cfd->full_options())) {
} else {
Version::GetStats stats;
super_version->current->Get(options, lkey, value, &s, &merge_context,
&stats, *cfd->full_options());
}
return s;
}
Iterator* DBImplReadOnly::NewIterator(const ReadOptions& options,
const ColumnFamilyHandle& column_family) {
auto cfd = versions_->GetColumnFamilySet()->GetColumnFamily(column_family.id);
assert(cfd != nullptr);
SuperVersion* super_version = cfd->GetSuperVersion()->Ref();
SequenceNumber latest_snapshot = versions_->LastSequence();
Iterator* internal_iter = NewInternalIterator(options, cfd, super_version);
return NewDBIterator(
&dbname_, env_, *cfd->full_options(), cfd->user_comparator(),
internal_iter,
(options.snapshot != nullptr
? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
: latest_snapshot));
}
Status DB::OpenForReadOnly(const Options& options, const std::string& dbname,
DB** dbptr, bool error_if_log_file_exist) {
*dbptr = nullptr;
DBOptions db_options(options);
ColumnFamilyOptions cf_options(options);
std::vector<ColumnFamilyDescriptor> column_families;
column_families.push_back(
ColumnFamilyDescriptor(default_column_family_name, cf_options));
DBImplReadOnly* impl = new DBImplReadOnly(db_options, dbname);
impl->mutex_.Lock();
Status s = impl->Recover(column_families, true /* read only */,
error_if_log_file_exist);
if (s.ok()) {
for (auto cfd : *impl->versions_->GetColumnFamilySet()) {
delete cfd->InstallSuperVersion(new SuperVersion());
}
}
impl->mutex_.Unlock();
if (s.ok()) {
*dbptr = impl;
} else {
delete impl;
}
return s;
}
}