e633983cf1
Summary: Leverage existing `FlushJob` to implement atomic flush of multiple column families. This PR depends on other PRs and is a subset of #3752 . This PR itself is not sufficient in fulfilling atomic flush. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4262 Differential Revision: D9283109 Pulled By: riversand963 fbshipit-source-id: 65401f913e4160b0a61c0be6cd02adc15dad28ed
763 lines
27 KiB
C++
763 lines
27 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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#include "db/memtable_list.h"
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#ifndef __STDC_FORMAT_MACROS
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#define __STDC_FORMAT_MACROS
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#endif
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#include <inttypes.h>
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#include <limits>
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#include <queue>
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#include <string>
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#include "db/db_impl.h"
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#include "db/memtable.h"
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#include "db/version_set.h"
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#include "monitoring/thread_status_util.h"
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#include "rocksdb/db.h"
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#include "rocksdb/env.h"
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#include "rocksdb/iterator.h"
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#include "table/merging_iterator.h"
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#include "util/coding.h"
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#include "util/log_buffer.h"
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#include "util/sync_point.h"
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namespace rocksdb {
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class InternalKeyComparator;
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class Mutex;
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class VersionSet;
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void MemTableListVersion::AddMemTable(MemTable* m) {
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memlist_.push_front(m);
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*parent_memtable_list_memory_usage_ += m->ApproximateMemoryUsage();
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}
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void MemTableListVersion::UnrefMemTable(autovector<MemTable*>* to_delete,
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MemTable* m) {
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if (m->Unref()) {
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to_delete->push_back(m);
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assert(*parent_memtable_list_memory_usage_ >= m->ApproximateMemoryUsage());
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*parent_memtable_list_memory_usage_ -= m->ApproximateMemoryUsage();
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}
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}
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MemTableListVersion::MemTableListVersion(
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size_t* parent_memtable_list_memory_usage, MemTableListVersion* old)
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: max_write_buffer_number_to_maintain_(
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old->max_write_buffer_number_to_maintain_),
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parent_memtable_list_memory_usage_(parent_memtable_list_memory_usage) {
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if (old != nullptr) {
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memlist_ = old->memlist_;
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for (auto& m : memlist_) {
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m->Ref();
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}
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memlist_history_ = old->memlist_history_;
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for (auto& m : memlist_history_) {
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m->Ref();
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}
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}
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}
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MemTableListVersion::MemTableListVersion(
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size_t* parent_memtable_list_memory_usage,
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int max_write_buffer_number_to_maintain)
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: max_write_buffer_number_to_maintain_(max_write_buffer_number_to_maintain),
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parent_memtable_list_memory_usage_(parent_memtable_list_memory_usage) {}
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void MemTableListVersion::Ref() { ++refs_; }
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// called by superversion::clean()
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void MemTableListVersion::Unref(autovector<MemTable*>* to_delete) {
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assert(refs_ >= 1);
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--refs_;
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if (refs_ == 0) {
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// if to_delete is equal to nullptr it means we're confident
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// that refs_ will not be zero
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assert(to_delete != nullptr);
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for (const auto& m : memlist_) {
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UnrefMemTable(to_delete, m);
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}
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for (const auto& m : memlist_history_) {
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UnrefMemTable(to_delete, m);
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}
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delete this;
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}
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}
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int MemTableList::NumNotFlushed() const {
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int size = static_cast<int>(current_->memlist_.size());
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assert(num_flush_not_started_ <= size);
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return size;
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}
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int MemTableList::NumFlushed() const {
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return static_cast<int>(current_->memlist_history_.size());
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}
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// Search all the memtables starting from the most recent one.
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// Return the most recent value found, if any.
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// Operands stores the list of merge operations to apply, so far.
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bool MemTableListVersion::Get(const LookupKey& key, std::string* value,
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Status* s, MergeContext* merge_context,
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RangeDelAggregator* range_del_agg,
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SequenceNumber* seq, const ReadOptions& read_opts,
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ReadCallback* callback, bool* is_blob_index) {
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return GetFromList(&memlist_, key, value, s, merge_context, range_del_agg,
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seq, read_opts, callback, is_blob_index);
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}
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bool MemTableListVersion::GetFromHistory(
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const LookupKey& key, std::string* value, Status* s,
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MergeContext* merge_context, RangeDelAggregator* range_del_agg,
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SequenceNumber* seq, const ReadOptions& read_opts, bool* is_blob_index) {
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return GetFromList(&memlist_history_, key, value, s, merge_context,
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range_del_agg, seq, read_opts, nullptr /*read_callback*/,
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is_blob_index);
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}
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bool MemTableListVersion::GetFromList(
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std::list<MemTable*>* list, const LookupKey& key, std::string* value,
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Status* s, MergeContext* merge_context, RangeDelAggregator* range_del_agg,
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SequenceNumber* seq, const ReadOptions& read_opts, ReadCallback* callback,
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bool* is_blob_index) {
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*seq = kMaxSequenceNumber;
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for (auto& memtable : *list) {
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SequenceNumber current_seq = kMaxSequenceNumber;
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bool done = memtable->Get(key, value, s, merge_context, range_del_agg,
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¤t_seq, read_opts, callback, is_blob_index);
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if (*seq == kMaxSequenceNumber) {
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// Store the most recent sequence number of any operation on this key.
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// Since we only care about the most recent change, we only need to
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// return the first operation found when searching memtables in
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// reverse-chronological order.
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// current_seq would be equal to kMaxSequenceNumber if the value was to be
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// skipped. This allows seq to be assigned again when the next value is
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// read.
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*seq = current_seq;
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}
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if (done) {
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assert(*seq != kMaxSequenceNumber);
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return true;
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}
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if (!done && !s->ok() && !s->IsMergeInProgress() && !s->IsNotFound()) {
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return false;
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}
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}
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return false;
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}
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Status MemTableListVersion::AddRangeTombstoneIterators(
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const ReadOptions& read_opts, Arena* /*arena*/,
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RangeDelAggregator* range_del_agg) {
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assert(range_del_agg != nullptr);
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for (auto& m : memlist_) {
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std::unique_ptr<InternalIterator> range_del_iter(
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m->NewRangeTombstoneIterator(read_opts));
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Status s = range_del_agg->AddTombstones(std::move(range_del_iter));
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if (!s.ok()) {
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return s;
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}
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}
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return Status::OK();
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}
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Status MemTableListVersion::AddRangeTombstoneIterators(
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const ReadOptions& read_opts,
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std::vector<InternalIterator*>* range_del_iters) {
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for (auto& m : memlist_) {
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auto* range_del_iter = m->NewRangeTombstoneIterator(read_opts);
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if (range_del_iter != nullptr) {
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range_del_iters->push_back(range_del_iter);
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}
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}
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return Status::OK();
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}
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void MemTableListVersion::AddIterators(
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const ReadOptions& options, std::vector<InternalIterator*>* iterator_list,
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Arena* arena) {
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for (auto& m : memlist_) {
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iterator_list->push_back(m->NewIterator(options, arena));
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}
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}
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void MemTableListVersion::AddIterators(
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const ReadOptions& options, MergeIteratorBuilder* merge_iter_builder) {
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for (auto& m : memlist_) {
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merge_iter_builder->AddIterator(
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m->NewIterator(options, merge_iter_builder->GetArena()));
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}
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}
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uint64_t MemTableListVersion::GetTotalNumEntries() const {
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uint64_t total_num = 0;
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for (auto& m : memlist_) {
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total_num += m->num_entries();
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}
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return total_num;
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}
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MemTable::MemTableStats MemTableListVersion::ApproximateStats(
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const Slice& start_ikey, const Slice& end_ikey) {
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MemTable::MemTableStats total_stats = {0, 0};
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for (auto& m : memlist_) {
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auto mStats = m->ApproximateStats(start_ikey, end_ikey);
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total_stats.size += mStats.size;
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total_stats.count += mStats.count;
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}
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return total_stats;
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}
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uint64_t MemTableListVersion::GetTotalNumDeletes() const {
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uint64_t total_num = 0;
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for (auto& m : memlist_) {
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total_num += m->num_deletes();
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}
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return total_num;
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}
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SequenceNumber MemTableListVersion::GetEarliestSequenceNumber(
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bool include_history) const {
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if (include_history && !memlist_history_.empty()) {
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return memlist_history_.back()->GetEarliestSequenceNumber();
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} else if (!memlist_.empty()) {
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return memlist_.back()->GetEarliestSequenceNumber();
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} else {
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return kMaxSequenceNumber;
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}
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}
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// caller is responsible for referencing m
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void MemTableListVersion::Add(MemTable* m, autovector<MemTable*>* to_delete) {
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assert(refs_ == 1); // only when refs_ == 1 is MemTableListVersion mutable
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AddMemTable(m);
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TrimHistory(to_delete);
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}
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// Removes m from list of memtables not flushed. Caller should NOT Unref m.
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void MemTableListVersion::Remove(MemTable* m,
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autovector<MemTable*>* to_delete) {
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assert(refs_ == 1); // only when refs_ == 1 is MemTableListVersion mutable
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memlist_.remove(m);
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m->MarkFlushed();
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if (max_write_buffer_number_to_maintain_ > 0) {
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memlist_history_.push_front(m);
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TrimHistory(to_delete);
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} else {
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UnrefMemTable(to_delete, m);
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}
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}
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// Make sure we don't use up too much space in history
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void MemTableListVersion::TrimHistory(autovector<MemTable*>* to_delete) {
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while (memlist_.size() + memlist_history_.size() >
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static_cast<size_t>(max_write_buffer_number_to_maintain_) &&
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!memlist_history_.empty()) {
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MemTable* x = memlist_history_.back();
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memlist_history_.pop_back();
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UnrefMemTable(to_delete, x);
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}
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}
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// Try to record multiple successful flush to the MANIFEST as an atomic unit.
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// This function may just return Status::OK if there has already been
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// a concurrent thread performing actual recording.
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Status MemTableList::TryInstallMemtableFlushResults(
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autovector<MemTableList*>& imm_lists,
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const autovector<ColumnFamilyData*>& cfds,
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const autovector<const MutableCFOptions*>& mutable_cf_options_list,
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const autovector<const autovector<MemTable*>*>& mems_list,
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bool* atomic_flush_commit_in_progress, LogsWithPrepTracker* prep_tracker,
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VersionSet* vset, InstrumentedMutex* mu,
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const autovector<FileMetaData>& file_metas,
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autovector<MemTable*>* to_delete, Directory* db_directory,
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LogBuffer* log_buffer) {
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AutoThreadOperationStageUpdater stage_updater(
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ThreadStatus::STAGE_MEMTABLE_INSTALL_FLUSH_RESULTS);
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mu->AssertHeld();
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for (size_t k = 0; k != mems_list.size(); ++k) {
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for (size_t i = 0; i != mems_list[k]->size(); ++i) {
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assert(i == 0 || (*mems_list[k])[i]->GetEdits()->NumEntries() == 0);
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(*mems_list[k])[i]->flush_completed_ = true;
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(*mems_list[k])[i]->file_number_ = file_metas[k].fd.GetNumber();
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}
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}
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assert(atomic_flush_commit_in_progress != nullptr);
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Status s;
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if (*atomic_flush_commit_in_progress) {
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// If the function reaches here, there must be a concurrent thread that
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// have already started recording to MANIFEST. Therefore we should just
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// return Status::OK and let the othe thread finish writing to MANIFEST on
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// our behalf.
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return s;
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}
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// If the function reaches here, the current thread will start writing to
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// MANIFEST. It may record to MANIFEST the flush results of other flushes.
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*atomic_flush_commit_in_progress = true;
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auto comp = [&imm_lists](size_t lh, size_t rh) {
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const auto& memlist1 = imm_lists[lh]->current_->memlist_;
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const auto& memlist2 = imm_lists[rh]->current_->memlist_;
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auto it1 = memlist1.rbegin();
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auto it2 = memlist2.rbegin();
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return (*it1)->atomic_flush_seqno_ > (*it2)->atomic_flush_seqno_;
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};
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// The top of the heap is the memtable with smallest atomic_flush_seqno_.
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std::priority_queue<size_t, std::vector<size_t>, decltype(comp)> heap(comp);
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// Sequence number of the oldest unfinished atomic flush.
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SequenceNumber min_unfinished_seqno = kMaxSequenceNumber;
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// Populate the heap with first element of each imm iff. it has been
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// flushed to storage, i.e. flush_completed_ is true.
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size_t num = imm_lists.size();
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assert(num == cfds.size());
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for (size_t i = 0; i != num; ++i) {
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std::list<MemTable*>& memlist = imm_lists[i]->current_->memlist_;
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if (memlist.empty()) {
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continue;
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}
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auto it = memlist.rbegin();
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if ((*it)->flush_completed_) {
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heap.emplace(i);
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} else if (min_unfinished_seqno > (*it)->atomic_flush_seqno_) {
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min_unfinished_seqno = (*it)->atomic_flush_seqno_;
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}
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}
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while (s.ok() && !heap.empty()) {
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autovector<size_t> batch;
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SequenceNumber seqno = kMaxSequenceNumber;
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// Pop from the heap the memtables that belong to the same atomic flush,
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// namely their atomic_flush_seqno_ are equal.
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do {
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size_t pos = heap.top();
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const auto& memlist = imm_lists[pos]->current_->memlist_;
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MemTable* mem = *(memlist.rbegin());
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if (seqno == kMaxSequenceNumber) {
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// First mem in this batch.
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seqno = mem->atomic_flush_seqno_;
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batch.emplace_back(pos);
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heap.pop();
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} else if (mem->atomic_flush_seqno_ == seqno) {
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// mem has the same atomic_flush_seqno_, thus in the same atomic flush.
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batch.emplace_back(pos);
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heap.pop();
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} else if (mem->atomic_flush_seqno_ > seqno) {
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// mem belongs to another atomic flush with higher seqno, break the
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// loop.
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break;
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}
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} while (!heap.empty());
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if (seqno >= min_unfinished_seqno) {
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// If there is an older, unfinished atomic flush, then we should not
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// proceed.
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TEST_SYNC_POINT_CALLBACK(
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"MemTableList::TryInstallMemtableFlushResults:"
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"HasOlderUnfinishedAtomicFlush:0",
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nullptr);
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break;
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}
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// Found the earliest, complete atomic flush. No earlier atomic flush is
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// pending. Therefore ready to record it to the MANIFEST.
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uint32_t num_entries = 0;
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autovector<ColumnFamilyData*> tmp_cfds;
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autovector<const MutableCFOptions*> tmp_mutable_cf_options_list;
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std::vector<autovector<MemTable*>> memtables_to_flush;
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autovector<autovector<VersionEdit*>> edit_lists;
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for (auto pos : batch) {
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tmp_cfds.emplace_back(cfds[pos]);
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tmp_mutable_cf_options_list.emplace_back(mutable_cf_options_list[pos]);
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const auto& memlist = imm_lists[pos]->current_->memlist_;
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uint64_t batch_file_number = 0;
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autovector<MemTable*> tmp_mems;
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autovector<VersionEdit*> edits;
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for (auto it = memlist.rbegin(); it != memlist.rend(); ++it) {
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MemTable* m = *it;
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if (!m->flush_completed_ ||
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(it != memlist.rbegin() && m->file_number_ != batch_file_number)) {
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break;
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}
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if (it == memlist.rbegin()) {
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batch_file_number = m->file_number_;
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edits.push_back(m->GetEdits());
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++num_entries;
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}
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tmp_mems.push_back(m);
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}
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edit_lists.push_back(edits);
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memtables_to_flush.push_back(tmp_mems);
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}
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TEST_SYNC_POINT_CALLBACK(
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"MemTableList::TryInstallMemtableFlushResults:FoundBatchToCommit:0",
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&num_entries);
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// Mark the version edits as an atomic group
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uint32_t remaining = num_entries;
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for (auto& edit_list : edit_lists) {
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assert(edit_list.size() == 1);
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edit_list[0]->MarkAtomicGroup(--remaining);
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}
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assert(remaining == 0);
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size_t batch_sz = batch.size();
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assert(batch_sz > 0);
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assert(batch_sz == memtables_to_flush.size());
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assert(batch_sz == tmp_cfds.size());
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assert(batch_sz == edit_lists.size());
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if (vset->db_options()->allow_2pc) {
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for (size_t i = 0; i != batch_sz; ++i) {
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auto& edit_list = edit_lists[i];
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assert(!edit_list.empty());
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edit_list.back()->SetMinLogNumberToKeep(
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PrecomputeMinLogNumberToKeep(vset, *tmp_cfds[i], edit_list,
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memtables_to_flush[i], prep_tracker));
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}
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}
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// this can release and reacquire the mutex.
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s = vset->LogAndApply(tmp_cfds, tmp_mutable_cf_options_list, edit_lists, mu,
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db_directory);
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for (const auto pos : batch) {
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imm_lists[pos]->InstallNewVersion();
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}
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if (s.ok()) {
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for (size_t i = 0; i != batch_sz; ++i) {
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if (tmp_cfds[i]->IsDropped()) {
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continue;
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}
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size_t pos = batch[i];
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for (auto m : memtables_to_flush[i]) {
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assert(m->file_number_ > 0);
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uint64_t mem_id = m->GetID();
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ROCKS_LOG_BUFFER(log_buffer,
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"[%s] Level-0 commit table #%" PRIu64
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": memtable #%" PRIu64 " done",
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tmp_cfds[i]->GetName().c_str(), m->file_number_,
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mem_id);
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imm_lists[pos]->current_->Remove(m, to_delete);
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}
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}
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} else {
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for (size_t i = 0; i != batch_sz; ++i) {
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size_t pos = batch[i];
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for (auto m : memtables_to_flush[i]) {
|
|
uint64_t mem_id = m->GetID();
|
|
ROCKS_LOG_BUFFER(log_buffer,
|
|
"[%s] Level-0 commit table #%" PRIu64
|
|
": memtable #%" PRIu64 " failed",
|
|
tmp_cfds[i]->GetName().c_str(), m->file_number_,
|
|
mem_id);
|
|
m->flush_completed_ = false;
|
|
m->flush_in_progress_ = false;
|
|
m->edit_.Clear();
|
|
m->file_number_ = 0;
|
|
imm_lists[pos]->num_flush_not_started_++;
|
|
}
|
|
imm_lists[pos]->imm_flush_needed.store(true, std::memory_order_release);
|
|
}
|
|
}
|
|
// Adjust the heap AFTER installing new MemTableListVersions because the
|
|
// compare function 'comp' needs to capture the most up-to-date state of
|
|
// imm_lists.
|
|
for (auto pos : batch) {
|
|
const auto& memlist = imm_lists[pos]->current_->memlist_;
|
|
if (!memlist.empty()) {
|
|
MemTable* mem = *(memlist.rbegin());
|
|
if (mem->flush_completed_) {
|
|
heap.emplace(pos);
|
|
} else if (min_unfinished_seqno > mem->atomic_flush_seqno_) {
|
|
min_unfinished_seqno = mem->atomic_flush_seqno_;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
*atomic_flush_commit_in_progress = false;
|
|
return s;
|
|
}
|
|
|
|
// Returns true if there is at least one memtable on which flush has
|
|
// not yet started.
|
|
bool MemTableList::IsFlushPending() const {
|
|
if ((flush_requested_ && num_flush_not_started_ > 0) ||
|
|
(num_flush_not_started_ >= min_write_buffer_number_to_merge_)) {
|
|
assert(imm_flush_needed.load(std::memory_order_relaxed));
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Returns the memtables that need to be flushed.
|
|
void MemTableList::PickMemtablesToFlush(const uint64_t* max_memtable_id,
|
|
autovector<MemTable*>* ret) {
|
|
AutoThreadOperationStageUpdater stage_updater(
|
|
ThreadStatus::STAGE_PICK_MEMTABLES_TO_FLUSH);
|
|
const auto& memlist = current_->memlist_;
|
|
for (auto it = memlist.rbegin(); it != memlist.rend(); ++it) {
|
|
MemTable* m = *it;
|
|
if (max_memtable_id != nullptr && m->GetID() > *max_memtable_id) {
|
|
break;
|
|
}
|
|
if (!m->flush_in_progress_) {
|
|
assert(!m->flush_completed_);
|
|
num_flush_not_started_--;
|
|
if (num_flush_not_started_ == 0) {
|
|
imm_flush_needed.store(false, std::memory_order_release);
|
|
}
|
|
m->flush_in_progress_ = true; // flushing will start very soon
|
|
ret->push_back(m);
|
|
}
|
|
}
|
|
flush_requested_ = false; // start-flush request is complete
|
|
}
|
|
|
|
void MemTableList::RollbackMemtableFlush(const autovector<MemTable*>& mems,
|
|
uint64_t /*file_number*/) {
|
|
AutoThreadOperationStageUpdater stage_updater(
|
|
ThreadStatus::STAGE_MEMTABLE_ROLLBACK);
|
|
assert(!mems.empty());
|
|
|
|
// If the flush was not successful, then just reset state.
|
|
// Maybe a succeeding attempt to flush will be successful.
|
|
for (MemTable* m : mems) {
|
|
assert(m->flush_in_progress_);
|
|
assert(m->file_number_ == 0);
|
|
|
|
m->flush_in_progress_ = false;
|
|
m->flush_completed_ = false;
|
|
m->edit_.Clear();
|
|
num_flush_not_started_++;
|
|
}
|
|
imm_flush_needed.store(true, std::memory_order_release);
|
|
}
|
|
|
|
// Try record a successful flush in the manifest file. It might just return
|
|
// Status::OK letting a concurrent flush to do actual the recording..
|
|
Status MemTableList::TryInstallMemtableFlushResults(
|
|
ColumnFamilyData* cfd, const MutableCFOptions& mutable_cf_options,
|
|
const autovector<MemTable*>& mems, LogsWithPrepTracker* prep_tracker,
|
|
VersionSet* vset, InstrumentedMutex* mu, uint64_t file_number,
|
|
autovector<MemTable*>* to_delete, Directory* db_directory,
|
|
LogBuffer* log_buffer) {
|
|
AutoThreadOperationStageUpdater stage_updater(
|
|
ThreadStatus::STAGE_MEMTABLE_INSTALL_FLUSH_RESULTS);
|
|
mu->AssertHeld();
|
|
|
|
// Flush was successful
|
|
// Record the status on the memtable object. Either this call or a call by a
|
|
// concurrent flush thread will read the status and write it to manifest.
|
|
for (size_t i = 0; i < mems.size(); ++i) {
|
|
// All the edits are associated with the first memtable of this batch.
|
|
assert(i == 0 || mems[i]->GetEdits()->NumEntries() == 0);
|
|
|
|
mems[i]->flush_completed_ = true;
|
|
mems[i]->file_number_ = file_number;
|
|
}
|
|
|
|
// if some other thread is already committing, then return
|
|
Status s;
|
|
if (commit_in_progress_) {
|
|
TEST_SYNC_POINT("MemTableList::TryInstallMemtableFlushResults:InProgress");
|
|
return s;
|
|
}
|
|
|
|
// Only a single thread can be executing this piece of code
|
|
commit_in_progress_ = true;
|
|
|
|
// Retry until all completed flushes are committed. New flushes can finish
|
|
// while the current thread is writing manifest where mutex is released.
|
|
while (s.ok()) {
|
|
auto& memlist = current_->memlist_;
|
|
// The back is the oldest; if flush_completed_ is not set to it, it means
|
|
// that we were assigned a more recent memtable. The memtables' flushes must
|
|
// be recorded in manifest in order. A concurrent flush thread, who is
|
|
// assigned to flush the oldest memtable, will later wake up and does all
|
|
// the pending writes to manifest, in order.
|
|
if (memlist.empty() || !memlist.back()->flush_completed_) {
|
|
break;
|
|
}
|
|
// scan all memtables from the earliest, and commit those
|
|
// (in that order) that have finished flushing. Memtables
|
|
// are always committed in the order that they were created.
|
|
uint64_t batch_file_number = 0;
|
|
size_t batch_count = 0;
|
|
autovector<VersionEdit*> edit_list;
|
|
autovector<MemTable*> memtables_to_flush;
|
|
// enumerate from the last (earliest) element to see how many batch finished
|
|
for (auto it = memlist.rbegin(); it != memlist.rend(); ++it) {
|
|
MemTable* m = *it;
|
|
if (!m->flush_completed_) {
|
|
break;
|
|
}
|
|
if (it == memlist.rbegin() || batch_file_number != m->file_number_) {
|
|
batch_file_number = m->file_number_;
|
|
ROCKS_LOG_BUFFER(log_buffer,
|
|
"[%s] Level-0 commit table #%" PRIu64 " started",
|
|
cfd->GetName().c_str(), m->file_number_);
|
|
edit_list.push_back(&m->edit_);
|
|
memtables_to_flush.push_back(m);
|
|
}
|
|
batch_count++;
|
|
}
|
|
|
|
// TODO(myabandeh): Not sure how batch_count could be 0 here.
|
|
if (batch_count > 0) {
|
|
if (vset->db_options()->allow_2pc) {
|
|
assert(edit_list.size() > 0);
|
|
// We piggyback the information of earliest log file to keep in the
|
|
// manifest entry for the last file flushed.
|
|
edit_list.back()->SetMinLogNumberToKeep(PrecomputeMinLogNumberToKeep(
|
|
vset, *cfd, edit_list, memtables_to_flush, prep_tracker));
|
|
}
|
|
|
|
// this can release and reacquire the mutex.
|
|
s = vset->LogAndApply(cfd, mutable_cf_options, edit_list, mu,
|
|
db_directory);
|
|
|
|
// we will be changing the version in the next code path,
|
|
// so we better create a new one, since versions are immutable
|
|
InstallNewVersion();
|
|
|
|
// All the later memtables that have the same filenum
|
|
// are part of the same batch. They can be committed now.
|
|
uint64_t mem_id = 1; // how many memtables have been flushed.
|
|
|
|
// commit new state only if the column family is NOT dropped.
|
|
// The reason is as follows (refer to
|
|
// ColumnFamilyTest.FlushAndDropRaceCondition).
|
|
// If the column family is dropped, then according to LogAndApply, its
|
|
// corresponding flush operation is NOT written to the MANIFEST. This
|
|
// means the DB is not aware of the L0 files generated from the flush.
|
|
// By committing the new state, we remove the memtable from the memtable
|
|
// list. Creating an iterator on this column family will not be able to
|
|
// read full data since the memtable is removed, and the DB is not aware
|
|
// of the L0 files, causing MergingIterator unable to build child
|
|
// iterators. RocksDB contract requires that the iterator can be created
|
|
// on a dropped column family, and we must be able to
|
|
// read full data as long as column family handle is not deleted, even if
|
|
// the column family is dropped.
|
|
if (s.ok() && !cfd->IsDropped()) { // commit new state
|
|
while (batch_count-- > 0) {
|
|
MemTable* m = current_->memlist_.back();
|
|
ROCKS_LOG_BUFFER(log_buffer, "[%s] Level-0 commit table #%" PRIu64
|
|
": memtable #%" PRIu64 " done",
|
|
cfd->GetName().c_str(), m->file_number_, mem_id);
|
|
assert(m->file_number_ > 0);
|
|
current_->Remove(m, to_delete);
|
|
++mem_id;
|
|
}
|
|
} else {
|
|
for (auto it = current_->memlist_.rbegin(); batch_count-- > 0; it++) {
|
|
MemTable* m = *it;
|
|
// commit failed. setup state so that we can flush again.
|
|
ROCKS_LOG_BUFFER(log_buffer, "Level-0 commit table #%" PRIu64
|
|
": memtable #%" PRIu64 " failed",
|
|
m->file_number_, mem_id);
|
|
m->flush_completed_ = false;
|
|
m->flush_in_progress_ = false;
|
|
m->edit_.Clear();
|
|
num_flush_not_started_++;
|
|
m->file_number_ = 0;
|
|
imm_flush_needed.store(true, std::memory_order_release);
|
|
++mem_id;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
commit_in_progress_ = false;
|
|
return s;
|
|
}
|
|
|
|
// New memtables are inserted at the front of the list.
|
|
void MemTableList::Add(MemTable* m, autovector<MemTable*>* to_delete) {
|
|
assert(static_cast<int>(current_->memlist_.size()) >= num_flush_not_started_);
|
|
InstallNewVersion();
|
|
// this method is used to move mutable memtable into an immutable list.
|
|
// since mutable memtable is already refcounted by the DBImpl,
|
|
// and when moving to the imutable list we don't unref it,
|
|
// we don't have to ref the memtable here. we just take over the
|
|
// reference from the DBImpl.
|
|
current_->Add(m, to_delete);
|
|
m->MarkImmutable();
|
|
num_flush_not_started_++;
|
|
if (num_flush_not_started_ == 1) {
|
|
imm_flush_needed.store(true, std::memory_order_release);
|
|
}
|
|
}
|
|
|
|
// Returns an estimate of the number of bytes of data in use.
|
|
size_t MemTableList::ApproximateUnflushedMemTablesMemoryUsage() {
|
|
size_t total_size = 0;
|
|
for (auto& memtable : current_->memlist_) {
|
|
total_size += memtable->ApproximateMemoryUsage();
|
|
}
|
|
return total_size;
|
|
}
|
|
|
|
size_t MemTableList::ApproximateMemoryUsage() { return current_memory_usage_; }
|
|
|
|
uint64_t MemTableList::ApproximateOldestKeyTime() const {
|
|
if (!current_->memlist_.empty()) {
|
|
return current_->memlist_.back()->ApproximateOldestKeyTime();
|
|
}
|
|
return std::numeric_limits<uint64_t>::max();
|
|
}
|
|
|
|
void MemTableList::InstallNewVersion() {
|
|
if (current_->refs_ == 1) {
|
|
// we're the only one using the version, just keep using it
|
|
} else {
|
|
// somebody else holds the current version, we need to create new one
|
|
MemTableListVersion* version = current_;
|
|
current_ = new MemTableListVersion(¤t_memory_usage_, current_);
|
|
current_->Ref();
|
|
version->Unref();
|
|
}
|
|
}
|
|
|
|
uint64_t MemTableList::PrecomputeMinLogContainingPrepSection(
|
|
const autovector<MemTable*>& memtables_to_flush) {
|
|
uint64_t min_log = 0;
|
|
|
|
for (auto& m : current_->memlist_) {
|
|
// Assume the list is very short, we can live with O(m*n). We can optimize
|
|
// if the performance has some problem.
|
|
bool should_skip = false;
|
|
for (MemTable* m_to_flush : memtables_to_flush) {
|
|
if (m == m_to_flush) {
|
|
should_skip = true;
|
|
break;
|
|
}
|
|
}
|
|
if (should_skip) {
|
|
continue;
|
|
}
|
|
|
|
auto log = m->GetMinLogContainingPrepSection();
|
|
|
|
if (log > 0 && (min_log == 0 || log < min_log)) {
|
|
min_log = log;
|
|
}
|
|
}
|
|
|
|
return min_log;
|
|
}
|
|
|
|
} // namespace rocksdb
|