mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-28 05:43:50 +00:00
a4a4a2dabd
Summary: Previously, a `ReadOptions` object was stored in every `BlockBasedTableIterator` and every `LevelIterator`. This redundancy consumes extra memory, resulting in the `Arena` making more allocations, and iteration observing worse cache performance. This PR migrates callers of `NewInternalIterator()` and `MakeInputIterator()` to provide a `ReadOptions` object guaranteed to outlive the returned iterator. When the iterator's lifetime will be managed by the user, this lifetime guarantee is achieved by storing the `ReadOptions` value in `ArenaWrappedDBIter`. Then, sub-iterators of `NewInternalIterator()` and `MakeInputIterator()` can hold a reference-to-const `ReadOptions`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7210 Test Plan: - `make check` under ASAN and valgrind - benchmark: on a DB with 2 L0 files and 3 L1+ levels, this PR reduced `Arena` allocation 4792 -> 4160 bytes. Reviewed By: anand1976 Differential Revision: D22861323 Pulled By: ajkr fbshipit-source-id: 54aebb3e89c872eeab0f5793b4b6e42878d093ce
109 lines
4.6 KiB
C++
109 lines
4.6 KiB
C++
// 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.
|
|
|
|
#include "db/arena_wrapped_db_iter.h"
|
|
#include "memory/arena.h"
|
|
#include "rocksdb/env.h"
|
|
#include "rocksdb/iterator.h"
|
|
#include "rocksdb/options.h"
|
|
#include "table/internal_iterator.h"
|
|
#include "table/iterator_wrapper.h"
|
|
#include "util/user_comparator_wrapper.h"
|
|
|
|
namespace ROCKSDB_NAMESPACE {
|
|
|
|
Status ArenaWrappedDBIter::GetProperty(std::string prop_name,
|
|
std::string* prop) {
|
|
if (prop_name == "rocksdb.iterator.super-version-number") {
|
|
// First try to pass the value returned from inner iterator.
|
|
if (!db_iter_->GetProperty(prop_name, prop).ok()) {
|
|
*prop = ToString(sv_number_);
|
|
}
|
|
return Status::OK();
|
|
}
|
|
return db_iter_->GetProperty(prop_name, prop);
|
|
}
|
|
|
|
void ArenaWrappedDBIter::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_iteration,
|
|
uint64_t version_number,
|
|
ReadCallback* read_callback, DBImpl* db_impl,
|
|
ColumnFamilyData* cfd, bool allow_blob,
|
|
bool allow_refresh) {
|
|
auto mem = arena_.AllocateAligned(sizeof(DBIter));
|
|
db_iter_ = new (mem) DBIter(env, read_options, cf_options, mutable_cf_options,
|
|
cf_options.user_comparator, nullptr, sequence,
|
|
true, max_sequential_skip_in_iteration,
|
|
read_callback, db_impl, cfd, allow_blob);
|
|
sv_number_ = version_number;
|
|
read_options_ = read_options;
|
|
allow_refresh_ = allow_refresh;
|
|
}
|
|
|
|
Status ArenaWrappedDBIter::Refresh() {
|
|
if (cfd_ == nullptr || db_impl_ == nullptr || !allow_refresh_) {
|
|
return Status::NotSupported("Creating renew iterator is not allowed.");
|
|
}
|
|
assert(db_iter_ != nullptr);
|
|
// TODO(yiwu): For last_seq_same_as_publish_seq_==false, this is not the
|
|
// correct behavior. Will be corrected automatically when we take a snapshot
|
|
// here for the case of WritePreparedTxnDB.
|
|
uint64_t cur_sv_number = cfd_->GetSuperVersionNumber();
|
|
TEST_SYNC_POINT("ArenaWrappedDBIter::Refresh:1");
|
|
TEST_SYNC_POINT("ArenaWrappedDBIter::Refresh:2");
|
|
if (sv_number_ != cur_sv_number) {
|
|
Env* env = db_iter_->env();
|
|
db_iter_->~DBIter();
|
|
arena_.~Arena();
|
|
new (&arena_) Arena();
|
|
|
|
SuperVersion* sv = cfd_->GetReferencedSuperVersion(db_impl_);
|
|
SequenceNumber latest_seq = db_impl_->GetLatestSequenceNumber();
|
|
if (read_callback_) {
|
|
read_callback_->Refresh(latest_seq);
|
|
}
|
|
Init(env, read_options_, *(cfd_->ioptions()), sv->mutable_cf_options,
|
|
latest_seq, sv->mutable_cf_options.max_sequential_skip_in_iterations,
|
|
cur_sv_number, read_callback_, db_impl_, cfd_, allow_blob_,
|
|
allow_refresh_);
|
|
|
|
InternalIterator* internal_iter = db_impl_->NewInternalIterator(
|
|
read_options_, cfd_, sv, &arena_, db_iter_->GetRangeDelAggregator(),
|
|
latest_seq, /* allow_unprepared_value */ true);
|
|
SetIterUnderDBIter(internal_iter);
|
|
} else {
|
|
db_iter_->set_sequence(db_impl_->GetLatestSequenceNumber());
|
|
db_iter_->set_valid(false);
|
|
}
|
|
return Status::OK();
|
|
}
|
|
|
|
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, ColumnFamilyData* cfd,
|
|
bool allow_blob, bool allow_refresh) {
|
|
ArenaWrappedDBIter* iter = new ArenaWrappedDBIter();
|
|
iter->Init(env, read_options, cf_options, mutable_cf_options, sequence,
|
|
max_sequential_skip_in_iterations, version_number, read_callback,
|
|
db_impl, cfd, allow_blob, allow_refresh);
|
|
if (db_impl != nullptr && cfd != nullptr && allow_refresh) {
|
|
iter->StoreRefreshInfo(db_impl, cfd, read_callback, allow_blob);
|
|
}
|
|
|
|
return iter;
|
|
}
|
|
|
|
} // namespace ROCKSDB_NAMESPACE
|