b06840aa7d
Summary: The change to the public behavior: * When opening a DB or creating new column family client gets a ColumnFamilyHandle. * As long as column family handle is alive, client can do whatever he wants with it, even drop it * Dropped column family can still be read from (using the column family handle) * Added a new call CloseColumnFamily(). Client has to close all column families that he has opened before deleting the DB * As soon as column family is closed, any calls to DB using that column family handle will fail (also any outstanding calls) Internally: * Ref-counting ColumnFamilyData * New thread-safety for ColumnFamilySet * Dropped column families are now completely dropped and their memory cleaned-up Test Plan: added some tests to column_family_test Reviewers: dhruba, haobo, kailiu, sdong CC: leveldb Differential Revision: https://reviews.facebook.net/D16101
119 lines
3.8 KiB
C++
119 lines
3.8 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 DBOptions& 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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ColumnFamilyHandle* column_family, const Slice& key,
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std::string* value) {
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Status s;
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SequenceNumber snapshot = versions_->LastSequence();
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auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
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auto cfd = cfh->cfd();
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SuperVersion* super_version = cfd->GetSuperVersion();
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MergeContext merge_context;
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LookupKey lkey(key, snapshot);
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if (super_version->mem->Get(lkey, value, &s, merge_context,
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*cfd->full_options())) {
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} else {
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Version::GetStats stats;
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super_version->current->Get(options, lkey, value, &s, &merge_context,
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&stats, *cfd->full_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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ColumnFamilyHandle* column_family) {
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auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
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auto cfd = cfh->cfd();
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SuperVersion* super_version = cfd->GetSuperVersion()->Ref();
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SequenceNumber latest_snapshot = versions_->LastSequence();
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Iterator* internal_iter = NewInternalIterator(options, cfd, super_version);
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return NewDBIterator(
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&dbname_, env_, *cfd->full_options(), cfd->user_comparator(),
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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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DBOptions db_options(options);
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ColumnFamilyOptions cf_options(options);
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std::vector<ColumnFamilyDescriptor> column_families;
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column_families.push_back(
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ColumnFamilyDescriptor(default_column_family_name, cf_options));
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DBImplReadOnly* impl = new DBImplReadOnly(db_options, dbname);
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impl->mutex_.Lock();
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Status s = impl->Recover(column_families, true /* read only */,
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error_if_log_file_exist);
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if (s.ok()) {
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for (auto cfd : *impl->versions_->GetColumnFamilySet()) {
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delete cfd->InstallSuperVersion(new SuperVersion());
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}
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}
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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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