1910560c2c
Summary: The bug fixed in https://github.com/facebook/rocksdb/pull/1816/ is now applicable to iterator too. This was not an issue but https://github.com/facebook/rocksdb/pull/2886 caused the regression. If a put and DB flush happens just between iterator to get latest sequence number and getting super version, empty result for the key or an older value can be returned, which is wrong. Fix it in the same way as the fix in https://github.com/facebook/rocksdb/issues/1816, that is to get the sequence number after referencing the super version. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6973 Test Plan: Will run stress tests for a while to make sure there is no general regression. Reviewed By: ajkr Differential Revision: D22029348 fbshipit-source-id: 94390f93630906796d6e2fec321f44a920953fd1
109 lines
4.6 KiB
C++
109 lines
4.6 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. 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. See the AUTHORS file for names of contributors.
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#include "db/arena_wrapped_db_iter.h"
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#include "memory/arena.h"
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#include "rocksdb/env.h"
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#include "rocksdb/iterator.h"
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#include "rocksdb/options.h"
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#include "table/internal_iterator.h"
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#include "table/iterator_wrapper.h"
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#include "util/user_comparator_wrapper.h"
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namespace ROCKSDB_NAMESPACE {
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Status ArenaWrappedDBIter::GetProperty(std::string prop_name,
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std::string* prop) {
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if (prop_name == "rocksdb.iterator.super-version-number") {
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// First try to pass the value returned from inner iterator.
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if (!db_iter_->GetProperty(prop_name, prop).ok()) {
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*prop = ToString(sv_number_);
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}
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return Status::OK();
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}
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return db_iter_->GetProperty(prop_name, prop);
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}
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void ArenaWrappedDBIter::Init(Env* env, const ReadOptions& read_options,
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const ImmutableCFOptions& cf_options,
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const MutableCFOptions& mutable_cf_options,
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const SequenceNumber& sequence,
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uint64_t max_sequential_skip_in_iteration,
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uint64_t version_number,
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ReadCallback* read_callback, DBImpl* db_impl,
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ColumnFamilyData* cfd, bool allow_blob,
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bool allow_refresh) {
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auto mem = arena_.AllocateAligned(sizeof(DBIter));
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db_iter_ = new (mem) DBIter(env, read_options, cf_options, mutable_cf_options,
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cf_options.user_comparator, nullptr, sequence,
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true, max_sequential_skip_in_iteration,
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read_callback, db_impl, cfd, allow_blob);
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sv_number_ = version_number;
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allow_refresh_ = allow_refresh;
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}
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Status ArenaWrappedDBIter::Refresh() {
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if (cfd_ == nullptr || db_impl_ == nullptr || !allow_refresh_) {
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return Status::NotSupported("Creating renew iterator is not allowed.");
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}
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assert(db_iter_ != nullptr);
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// TODO(yiwu): For last_seq_same_as_publish_seq_==false, this is not the
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// correct behavior. Will be corrected automatically when we take a snapshot
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// here for the case of WritePreparedTxnDB.
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uint64_t cur_sv_number = cfd_->GetSuperVersionNumber();
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TEST_SYNC_POINT("ArenaWrappedDBIter::Refresh:1");
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TEST_SYNC_POINT("ArenaWrappedDBIter::Refresh:2");
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if (sv_number_ != cur_sv_number) {
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Env* env = db_iter_->env();
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db_iter_->~DBIter();
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arena_.~Arena();
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new (&arena_) Arena();
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SuperVersion* sv = cfd_->GetReferencedSuperVersion(db_impl_);
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SequenceNumber latest_seq = db_impl_->GetLatestSequenceNumber();
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if (read_callback_) {
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read_callback_->Refresh(latest_seq);
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}
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Init(env, read_options_, *(cfd_->ioptions()), sv->mutable_cf_options,
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latest_seq, sv->mutable_cf_options.max_sequential_skip_in_iterations,
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cur_sv_number, read_callback_, db_impl_, cfd_, allow_blob_,
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allow_refresh_);
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InternalIterator* internal_iter = db_impl_->NewInternalIterator(
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read_options_, cfd_, sv, &arena_, db_iter_->GetRangeDelAggregator(),
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latest_seq, /* allow_unprepared_value */ true);
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SetIterUnderDBIter(internal_iter);
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} else {
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db_iter_->set_sequence(db_impl_->GetLatestSequenceNumber());
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db_iter_->set_valid(false);
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}
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return Status::OK();
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}
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ArenaWrappedDBIter* NewArenaWrappedDbIterator(
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Env* env, const ReadOptions& read_options,
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const ImmutableCFOptions& cf_options,
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const MutableCFOptions& mutable_cf_options, const SequenceNumber& sequence,
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uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
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ReadCallback* read_callback, DBImpl* db_impl, ColumnFamilyData* cfd,
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bool allow_blob, bool allow_refresh) {
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ArenaWrappedDBIter* iter = new ArenaWrappedDBIter();
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iter->Init(env, read_options, cf_options, mutable_cf_options, sequence,
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max_sequential_skip_in_iterations, version_number, read_callback,
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db_impl, cfd, allow_blob, allow_refresh);
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if (db_impl != nullptr && cfd != nullptr && allow_refresh) {
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iter->StoreRefreshInfo(read_options, db_impl, cfd, read_callback,
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allow_blob);
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}
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return iter;
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}
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} // namespace ROCKSDB_NAMESPACE
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