d705755e52
Summary: One of our profilings shows that Version::Get() sometimes is slow when getting pointer of user comparators or other global objects. In this patch: (1) we keep pointers of immutable objects in Version to avoid accesses them though option objects or cfd objects (2) table_reader is directly cached in FileMetaData so that table cache don't have to go through handle first to fetch it (3) If level 0 has less than 3 files, skip the filtering logic based on SST tables' key range. Smallest and largest key are stored in separated memory locations, which has potential cache misses Test Plan: make all check Reviewers: haobo, ljin Reviewed By: haobo CC: igor, yhchiang, nkg-, leveldb Differential Revision: https://reviews.facebook.net/D17739 Conflicts: db/db_impl.cc db/db_impl_readonly.cc db/table_cache.cc db/version_edit.h db/version_set.cc db/version_set.h
103 lines
3.0 KiB
C++
103 lines
3.0 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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SequenceNumber snapshot = versions_->LastSequence();
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SuperVersion* super_version = 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, 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);
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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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Status s = impl->Recover(true /* read only */, error_if_log_file_exist);
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if (s.ok()) {
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delete impl->InstallSuperVersion(new DBImpl::SuperVersion());
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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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} // namespace rocksdb
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