Summary: It also renames InstallMemtableFlushResults to MaybeInstallMemtableFlushResults to clarify its contract. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4464 Differential Revision: D10224918 Pulled By: maysamyabandeh fbshipit-source-id: 04e3f2d8542002cb9f8010cb436f5152751b3cbe
536 lines
19 KiB
C++
536 lines
19 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).
|
|
//
|
|
#include "db/memtable_list.h"
|
|
|
|
#ifndef __STDC_FORMAT_MACROS
|
|
#define __STDC_FORMAT_MACROS
|
|
#endif
|
|
|
|
#include <inttypes.h>
|
|
#include <limits>
|
|
#include <string>
|
|
#include "db/db_impl.h"
|
|
#include "db/memtable.h"
|
|
#include "db/version_set.h"
|
|
#include "monitoring/thread_status_util.h"
|
|
#include "rocksdb/db.h"
|
|
#include "rocksdb/env.h"
|
|
#include "rocksdb/iterator.h"
|
|
#include "table/merging_iterator.h"
|
|
#include "util/coding.h"
|
|
#include "util/log_buffer.h"
|
|
#include "util/sync_point.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
class InternalKeyComparator;
|
|
class Mutex;
|
|
class VersionSet;
|
|
|
|
void MemTableListVersion::AddMemTable(MemTable* m) {
|
|
memlist_.push_front(m);
|
|
*parent_memtable_list_memory_usage_ += m->ApproximateMemoryUsage();
|
|
}
|
|
|
|
void MemTableListVersion::UnrefMemTable(autovector<MemTable*>* to_delete,
|
|
MemTable* m) {
|
|
if (m->Unref()) {
|
|
to_delete->push_back(m);
|
|
assert(*parent_memtable_list_memory_usage_ >= m->ApproximateMemoryUsage());
|
|
*parent_memtable_list_memory_usage_ -= m->ApproximateMemoryUsage();
|
|
}
|
|
}
|
|
|
|
MemTableListVersion::MemTableListVersion(
|
|
size_t* parent_memtable_list_memory_usage, MemTableListVersion* old)
|
|
: max_write_buffer_number_to_maintain_(
|
|
old->max_write_buffer_number_to_maintain_),
|
|
parent_memtable_list_memory_usage_(parent_memtable_list_memory_usage) {
|
|
if (old != nullptr) {
|
|
memlist_ = old->memlist_;
|
|
for (auto& m : memlist_) {
|
|
m->Ref();
|
|
}
|
|
|
|
memlist_history_ = old->memlist_history_;
|
|
for (auto& m : memlist_history_) {
|
|
m->Ref();
|
|
}
|
|
}
|
|
}
|
|
|
|
MemTableListVersion::MemTableListVersion(
|
|
size_t* parent_memtable_list_memory_usage,
|
|
int max_write_buffer_number_to_maintain)
|
|
: max_write_buffer_number_to_maintain_(max_write_buffer_number_to_maintain),
|
|
parent_memtable_list_memory_usage_(parent_memtable_list_memory_usage) {}
|
|
|
|
void MemTableListVersion::Ref() { ++refs_; }
|
|
|
|
// called by superversion::clean()
|
|
void MemTableListVersion::Unref(autovector<MemTable*>* to_delete) {
|
|
assert(refs_ >= 1);
|
|
--refs_;
|
|
if (refs_ == 0) {
|
|
// if to_delete is equal to nullptr it means we're confident
|
|
// that refs_ will not be zero
|
|
assert(to_delete != nullptr);
|
|
for (const auto& m : memlist_) {
|
|
UnrefMemTable(to_delete, m);
|
|
}
|
|
for (const auto& m : memlist_history_) {
|
|
UnrefMemTable(to_delete, m);
|
|
}
|
|
delete this;
|
|
}
|
|
}
|
|
|
|
int MemTableList::NumNotFlushed() const {
|
|
int size = static_cast<int>(current_->memlist_.size());
|
|
assert(num_flush_not_started_ <= size);
|
|
return size;
|
|
}
|
|
|
|
int MemTableList::NumFlushed() const {
|
|
return static_cast<int>(current_->memlist_history_.size());
|
|
}
|
|
|
|
// Search all the memtables starting from the most recent one.
|
|
// Return the most recent value found, if any.
|
|
// Operands stores the list of merge operations to apply, so far.
|
|
bool MemTableListVersion::Get(const LookupKey& key, std::string* value,
|
|
Status* s, MergeContext* merge_context,
|
|
RangeDelAggregator* range_del_agg,
|
|
SequenceNumber* seq, const ReadOptions& read_opts,
|
|
ReadCallback* callback, bool* is_blob_index) {
|
|
return GetFromList(&memlist_, key, value, s, merge_context, range_del_agg,
|
|
seq, read_opts, callback, is_blob_index);
|
|
}
|
|
|
|
bool MemTableListVersion::GetFromHistory(
|
|
const LookupKey& key, std::string* value, Status* s,
|
|
MergeContext* merge_context, RangeDelAggregator* range_del_agg,
|
|
SequenceNumber* seq, const ReadOptions& read_opts, bool* is_blob_index) {
|
|
return GetFromList(&memlist_history_, key, value, s, merge_context,
|
|
range_del_agg, seq, read_opts, nullptr /*read_callback*/,
|
|
is_blob_index);
|
|
}
|
|
|
|
bool MemTableListVersion::GetFromList(
|
|
std::list<MemTable*>* list, const LookupKey& key, std::string* value,
|
|
Status* s, MergeContext* merge_context, RangeDelAggregator* range_del_agg,
|
|
SequenceNumber* seq, const ReadOptions& read_opts, ReadCallback* callback,
|
|
bool* is_blob_index) {
|
|
*seq = kMaxSequenceNumber;
|
|
|
|
for (auto& memtable : *list) {
|
|
SequenceNumber current_seq = kMaxSequenceNumber;
|
|
|
|
bool done = memtable->Get(key, value, s, merge_context, range_del_agg,
|
|
¤t_seq, read_opts, callback, is_blob_index);
|
|
if (*seq == kMaxSequenceNumber) {
|
|
// Store the most recent sequence number of any operation on this key.
|
|
// Since we only care about the most recent change, we only need to
|
|
// return the first operation found when searching memtables in
|
|
// reverse-chronological order.
|
|
// current_seq would be equal to kMaxSequenceNumber if the value was to be
|
|
// skipped. This allows seq to be assigned again when the next value is
|
|
// read.
|
|
*seq = current_seq;
|
|
}
|
|
|
|
if (done) {
|
|
assert(*seq != kMaxSequenceNumber);
|
|
return true;
|
|
}
|
|
if (!done && !s->ok() && !s->IsMergeInProgress() && !s->IsNotFound()) {
|
|
return false;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
Status MemTableListVersion::AddRangeTombstoneIterators(
|
|
const ReadOptions& read_opts, Arena* /*arena*/,
|
|
RangeDelAggregator* range_del_agg) {
|
|
assert(range_del_agg != nullptr);
|
|
for (auto& m : memlist_) {
|
|
std::unique_ptr<InternalIterator> range_del_iter(
|
|
m->NewRangeTombstoneIterator(read_opts));
|
|
Status s = range_del_agg->AddTombstones(std::move(range_del_iter));
|
|
if (!s.ok()) {
|
|
return s;
|
|
}
|
|
}
|
|
return Status::OK();
|
|
}
|
|
|
|
Status MemTableListVersion::AddRangeTombstoneIterators(
|
|
const ReadOptions& read_opts,
|
|
std::vector<InternalIterator*>* range_del_iters) {
|
|
for (auto& m : memlist_) {
|
|
auto* range_del_iter = m->NewRangeTombstoneIterator(read_opts);
|
|
if (range_del_iter != nullptr) {
|
|
range_del_iters->push_back(range_del_iter);
|
|
}
|
|
}
|
|
return Status::OK();
|
|
}
|
|
|
|
void MemTableListVersion::AddIterators(
|
|
const ReadOptions& options, std::vector<InternalIterator*>* iterator_list,
|
|
Arena* arena) {
|
|
for (auto& m : memlist_) {
|
|
iterator_list->push_back(m->NewIterator(options, arena));
|
|
}
|
|
}
|
|
|
|
void MemTableListVersion::AddIterators(
|
|
const ReadOptions& options, MergeIteratorBuilder* merge_iter_builder) {
|
|
for (auto& m : memlist_) {
|
|
merge_iter_builder->AddIterator(
|
|
m->NewIterator(options, merge_iter_builder->GetArena()));
|
|
}
|
|
}
|
|
|
|
uint64_t MemTableListVersion::GetTotalNumEntries() const {
|
|
uint64_t total_num = 0;
|
|
for (auto& m : memlist_) {
|
|
total_num += m->num_entries();
|
|
}
|
|
return total_num;
|
|
}
|
|
|
|
MemTable::MemTableStats MemTableListVersion::ApproximateStats(
|
|
const Slice& start_ikey, const Slice& end_ikey) {
|
|
MemTable::MemTableStats total_stats = {0, 0};
|
|
for (auto& m : memlist_) {
|
|
auto mStats = m->ApproximateStats(start_ikey, end_ikey);
|
|
total_stats.size += mStats.size;
|
|
total_stats.count += mStats.count;
|
|
}
|
|
return total_stats;
|
|
}
|
|
|
|
uint64_t MemTableListVersion::GetTotalNumDeletes() const {
|
|
uint64_t total_num = 0;
|
|
for (auto& m : memlist_) {
|
|
total_num += m->num_deletes();
|
|
}
|
|
return total_num;
|
|
}
|
|
|
|
SequenceNumber MemTableListVersion::GetEarliestSequenceNumber(
|
|
bool include_history) const {
|
|
if (include_history && !memlist_history_.empty()) {
|
|
return memlist_history_.back()->GetEarliestSequenceNumber();
|
|
} else if (!memlist_.empty()) {
|
|
return memlist_.back()->GetEarliestSequenceNumber();
|
|
} else {
|
|
return kMaxSequenceNumber;
|
|
}
|
|
}
|
|
|
|
// caller is responsible for referencing m
|
|
void MemTableListVersion::Add(MemTable* m, autovector<MemTable*>* to_delete) {
|
|
assert(refs_ == 1); // only when refs_ == 1 is MemTableListVersion mutable
|
|
AddMemTable(m);
|
|
|
|
TrimHistory(to_delete);
|
|
}
|
|
|
|
// Removes m from list of memtables not flushed. Caller should NOT Unref m.
|
|
void MemTableListVersion::Remove(MemTable* m,
|
|
autovector<MemTable*>* to_delete) {
|
|
assert(refs_ == 1); // only when refs_ == 1 is MemTableListVersion mutable
|
|
memlist_.remove(m);
|
|
|
|
m->MarkFlushed();
|
|
if (max_write_buffer_number_to_maintain_ > 0) {
|
|
memlist_history_.push_front(m);
|
|
TrimHistory(to_delete);
|
|
} else {
|
|
UnrefMemTable(to_delete, m);
|
|
}
|
|
}
|
|
|
|
// Make sure we don't use up too much space in history
|
|
void MemTableListVersion::TrimHistory(autovector<MemTable*>* to_delete) {
|
|
while (memlist_.size() + memlist_history_.size() >
|
|
static_cast<size_t>(max_write_buffer_number_to_maintain_) &&
|
|
!memlist_history_.empty()) {
|
|
MemTable* x = memlist_history_.back();
|
|
memlist_history_.pop_back();
|
|
|
|
UnrefMemTable(to_delete, x);
|
|
}
|
|
}
|
|
|
|
// 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_ >= 1) ||
|
|
(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(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 (!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
|