rocksdb/db/compaction_job.h
Igor Canadi 35ca59364c Don't let flushes preempt compactions
Summary:
When we first started, max_background_flushes was 0 by default and compaction thread was executing flushes (since there was no flush thread). Then, we switched the default max_background_flushes to 1. However, we still support the case where there is no flush thread and flushes are done in compaction. This is making our code a bit more complicated. By not supporting this use-case we can make our code simpler.

We have a special case that when you set max_background_flushes to 0, we
schedule the flush to execute on the compaction thread.

Test Plan: make check (there might be some unit tests that depend on this behavior)

Reviewers: IslamAbdelRahman, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D41931
2015-07-17 12:02:52 -07:00

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5 KiB
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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same 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.
#pragma once
#include <atomic>
#include <deque>
#include <limits>
#include <set>
#include <utility>
#include <vector>
#include <string>
#include <functional>
#include "db/dbformat.h"
#include "db/log_writer.h"
#include "db/column_family.h"
#include "db/version_edit.h"
#include "db/memtable_list.h"
#include "port/port.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/memtablerep.h"
#include "rocksdb/compaction_filter.h"
#include "rocksdb/compaction_job_stats.h"
#include "rocksdb/transaction_log.h"
#include "util/autovector.h"
#include "util/event_logger.h"
#include "util/stop_watch.h"
#include "util/thread_local.h"
#include "util/scoped_arena_iterator.h"
#include "db/internal_stats.h"
#include "db/write_controller.h"
#include "db/flush_scheduler.h"
#include "db/write_thread.h"
#include "db/job_context.h"
namespace rocksdb {
class MemTable;
class TableCache;
class Version;
class VersionEdit;
class VersionSet;
class Arena;
class CompactionJob {
public:
CompactionJob(int job_id, Compaction* compaction, const DBOptions& db_options,
const EnvOptions& env_options, VersionSet* versions,
std::atomic<bool>* shutting_down, LogBuffer* log_buffer,
Directory* db_directory, Directory* output_directory,
Statistics* stats,
std::vector<SequenceNumber> existing_snapshots,
std::shared_ptr<Cache> table_cache,
EventLogger* event_logger, bool paranoid_file_checks,
const std::string& dbname,
CompactionJobStats* compaction_job_stats);
~CompactionJob();
// no copy/move
CompactionJob(CompactionJob&& job) = delete;
CompactionJob(const CompactionJob& job) = delete;
CompactionJob& operator=(const CompactionJob& job) = delete;
// REQUIRED: mutex held
void Prepare();
// REQUIRED mutex not held
Status Run();
// REQUIRED: mutex held
// status is the return of Run()
void Install(Status* status, const MutableCFOptions& mutable_cf_options,
InstrumentedMutex* db_mutex);
private:
// update the thread status for starting a compaction.
void ReportStartedCompaction(Compaction* compaction);
void AllocateCompactionOutputFileNumbers();
// Call compaction filter. Then iterate through input and compact the
// kv-pairs
Status ProcessKeyValueCompaction(int64_t* imm_micros, Iterator* input);
Status WriteKeyValue(const Slice& key, const Slice& value,
const ParsedInternalKey& ikey,
const Status& input_status);
Status FinishCompactionOutputFile(const Status& input_status);
Status InstallCompactionResults(InstrumentedMutex* db_mutex,
const MutableCFOptions& mutable_cf_options);
SequenceNumber findEarliestVisibleSnapshot(
SequenceNumber in, const std::vector<SequenceNumber>& snapshots,
SequenceNumber* prev_snapshot);
void RecordCompactionIOStats();
Status OpenCompactionOutputFile();
void CleanupCompaction(const Status& status);
void UpdateCompactionJobStats(
const InternalStats::CompactionStats& stats) const;
void RecordDroppedKeys(int64_t* key_drop_user,
int64_t* key_drop_newer_entry,
int64_t* key_drop_obsolete);
void UpdateCompactionStats();
void UpdateCompactionInputStatsHelper(
int* num_files, uint64_t* bytes_read, int input_level);
void LogCompaction(ColumnFamilyData* cfd, Compaction* compaction);
int job_id_;
// CompactionJob state
struct CompactionState;
CompactionState* compact_;
CompactionJobStats* compaction_job_stats_;
bool bottommost_level_;
SequenceNumber earliest_snapshot_;
SequenceNumber visible_at_tip_;
SequenceNumber latest_snapshot_;
InternalStats::CompactionStats compaction_stats_;
// DBImpl state
const std::string& dbname_;
const DBOptions& db_options_;
const EnvOptions& env_options_;
Env* env_;
VersionSet* versions_;
std::atomic<bool>* shutting_down_;
LogBuffer* log_buffer_;
Directory* db_directory_;
Directory* output_directory_;
Statistics* stats_;
// If there were two snapshots with seq numbers s1 and
// s2 and s1 < s2, and if we find two instances of a key k1 then lies
// entirely within s1 and s2, then the earlier version of k1 can be safely
// deleted because that version is not visible in any snapshot.
std::vector<SequenceNumber> existing_snapshots_;
std::shared_ptr<Cache> table_cache_;
EventLogger* event_logger_;
bool paranoid_file_checks_;
};
} // namespace rocksdb