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// 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.
#pragma once
#include <atomic>
#include <deque>
#include <functional>
#include <limits>
#include <set>
#include <string>
#include <utility>
#include <vector>
#include "db/blob/blob_file_completion_callback.h"
#include "db/column_family.h"
#include "db/compaction/compaction_iterator.h"
#include "db/compaction/compaction_outputs.h"
#include "db/flush_scheduler.h"
#include "db/internal_stats.h"
#include "db/job_context.h"
#include "db/log_writer.h"
#include "db/memtable_list.h"
#include "db/range_del_aggregator.h"
#include "db/seqno_to_time_mapping.h"
#include "db/version_edit.h"
#include "db/write_controller.h"
#include "db/write_thread.h"
#include "logging/event_logger.h"
#include "options/cf_options.h"
#include "options/db_options.h"
#include "port/port.h"
#include "rocksdb/compaction_filter.h"
#include "rocksdb/compaction_job_stats.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/memtablerep.h"
#include "rocksdb/transaction_log.h"
#include "table/scoped_arena_iterator.h"
#include "util/autovector.h"
#include "util/stop_watch.h"
#include "util/thread_local.h"
namespace ROCKSDB_NAMESPACE {
class Arena;
class CompactionState;
class ErrorHandler;
class MemTable;
class SnapshotChecker;
class SystemClock;
class TableCache;
class Version;
class VersionEdit;
class VersionSet;
class SubcompactionState;
// CompactionJob is responsible for executing the compaction. Each (manual or
// automated) compaction corresponds to a CompactionJob object, and usually
// goes through the stages of `Prepare()`->`Run()`->`Install()`. CompactionJob
// will divide the compaction into subcompactions and execute them in parallel
// if needed.
//
// CompactionJob has 2 main stats:
// 1. CompactionJobStats compaction_job_stats_
// CompactionJobStats is a public data structure which is part of Compaction
// event listener that rocksdb share the job stats with the user.
// Internally it's an aggregation of all the compaction_job_stats from each
// `SubcompactionState`:
// +------------------------+
// | SubcompactionState |
// | |
// +--------->| compaction_job_stats |
// | | |
// | +------------------------+
// +------------------------+ |
// | CompactionJob | | +------------------------+
// | | | | SubcompactionState |
// | compaction_job_stats +-----+ | |
// | | +--------->| compaction_job_stats |
// | | | | |
// +------------------------+ | +------------------------+
// |
// | +------------------------+
// | | SubcompactionState |
// | | |
// +--------->+ compaction_job_stats |
// | | |
// | +------------------------+
// |
// | +------------------------+
// | | ... |
// +--------->+ |
// +------------------------+
//
// 2. CompactionStatsFull compaction_stats_
// `CompactionStatsFull` is an internal stats about the compaction, which
// is eventually sent to `ColumnFamilyData::internal_stats_` and used for
// logging and public metrics.
// Internally, it's an aggregation of stats_ from each `SubcompactionState`.
// It has 2 parts, normal stats about the main compaction information and
// the penultimate level output stats.
// `SubcompactionState` maintains the CompactionOutputs for normal output and
// the penultimate level output if exists, the per_level stats is
// stored with the outputs.
// +---------------------------+
// | SubcompactionState |
// | |
// | +----------------------+ |
// | | CompactionOutputs | |
// | | (normal output) | |
// +---->| stats_ | |
// | | +----------------------+ |
// | | |
// | | +----------------------+ |
// +--------------------------------+ | | | CompactionOutputs | |
// | CompactionJob | | | | (penultimate_level) | |
// | | +--------->| stats_ | |
// | compaction_stats_ | | | | +----------------------+ |
// | +-------------------------+ | | | | |
// | |stats (normal) |------|----+ +---------------------------+
// | +-------------------------+ | | |
// | | | |
// | +-------------------------+ | | | +---------------------------+
// | |penultimate_level_stats +------+ | | SubcompactionState |
// | +-------------------------+ | | | | |
// | | | | | +----------------------+ |
// | | | | | | CompactionOutputs | |
// +--------------------------------+ | | | | (normal output) | |
// | +---->| stats_ | |
// | | +----------------------+ |
// | | |
// | | +----------------------+ |
// | | | CompactionOutputs | |
// | | | (penultimate_level) | |
// +--------->| stats_ | |
// | +----------------------+ |
// | |
// +---------------------------+
class CompactionJob {
public:
CompactionJob(
int job_id, Compaction* compaction, const ImmutableDBOptions& db_options,
const MutableDBOptions& mutable_db_options,
const FileOptions& file_options, VersionSet* versions,
const std::atomic<bool>* shutting_down, LogBuffer* log_buffer,
FSDirectory* db_directory, FSDirectory* output_directory,
FSDirectory* blob_output_directory, Statistics* stats,
InstrumentedMutex* db_mutex, ErrorHandler* db_error_handler,
std::vector<SequenceNumber> existing_snapshots,
SequenceNumber earliest_write_conflict_snapshot,
const SnapshotChecker* snapshot_checker, JobContext* job_context,
std::shared_ptr<Cache> table_cache, EventLogger* event_logger,
bool paranoid_file_checks, bool measure_io_stats,
const std::string& dbname, CompactionJobStats* compaction_job_stats,
Env::Priority thread_pri, const std::shared_ptr<IOTracer>& io_tracer,
const std::atomic<bool>& manual_compaction_canceled,
const std::string& db_id = "", const std::string& db_session_id = "",
std::string full_history_ts_low = "", std::string trim_ts = "",
BlobFileCompletionCallback* blob_callback = nullptr,
int* bg_compaction_scheduled = nullptr,
int* bg_bottom_compaction_scheduled = nullptr);
virtual ~CompactionJob();
// no copy/move
CompactionJob(CompactionJob&& job) = delete;
CompactionJob(const CompactionJob& job) = delete;
CompactionJob& operator=(const CompactionJob& job) = delete;
// REQUIRED: mutex held
// Prepare for the compaction by setting up boundaries for each subcompaction
void Prepare();
// REQUIRED mutex not held
// Launch threads for each subcompaction and wait for them to finish. After
// that, verify table is usable and finally do bookkeeping to unify
// subcompaction results
Status Run();
// REQUIRED: mutex held
// Add compaction input/output to the current version
Status Install(const MutableCFOptions& mutable_cf_options);
// Return the IO status
IOStatus io_status() const { return io_status_; }
protected:
// Update the following stats in compaction_stats_.stats
// - num_input_files_in_non_output_levels
// - num_input_files_in_output_level
// - bytes_read_non_output_levels
// - bytes_read_output_level
// - num_input_records
// - bytes_read_blob
// - num_dropped_records
//
// @param num_input_range_del if non-null, will be set to the number of range
// deletion entries in this compaction input.
//
// Returns true iff compaction_stats_.stats.num_input_records and
// num_input_range_del are calculated successfully.
bool UpdateCompactionStats(uint64_t* num_input_range_del = nullptr);
void LogCompaction();
virtual void RecordCompactionIOStats();
void CleanupCompaction();
// Call compaction filter. Then iterate through input and compact the
// kv-pairs
void ProcessKeyValueCompaction(SubcompactionState* sub_compact);
CompactionState* compact_;
InternalStats::CompactionStatsFull compaction_stats_;
const ImmutableDBOptions& db_options_;
const MutableDBOptions mutable_db_options_copy_;
LogBuffer* log_buffer_;
FSDirectory* output_directory_;
Statistics* stats_;
// Is this compaction creating a file in the bottom most level?
bool bottommost_level_;
Env::WriteLifeTimeHint write_hint_;
IOStatus io_status_;
CompactionJobStats* compaction_job_stats_;
private:
friend class CompactionJobTestBase;
// Generates a histogram representing potential divisions of key ranges from
// the input. It adds the starting and/or ending keys of certain input files
// to the working set and then finds the approximate size of data in between
// each consecutive pair of slices. Then it divides these ranges into
// consecutive groups such that each group has a similar size.
void GenSubcompactionBoundaries();
// Get the number of planned subcompactions based on max_subcompactions and
// extra reserved resources
uint64_t GetSubcompactionsLimit();
// Additional reserved threads are reserved and the number is stored in
// extra_num_subcompaction_threads_reserved__. For now, this happens only if
// the compaction priority is round-robin and max_subcompactions is not
// sufficient (extra resources may be needed)
void AcquireSubcompactionResources(int num_extra_required_subcompactions);
// Additional threads may be reserved during IncreaseSubcompactionResources()
// if num_actual_subcompactions is less than num_planned_subcompactions.
// Additional threads will be released and the bg_compaction_scheduled_ or
// bg_bottom_compaction_scheduled_ will be updated if they are used.
// DB Mutex lock is required.
void ShrinkSubcompactionResources(uint64_t num_extra_resources);
// Release all reserved threads and update the compaction limits.
void ReleaseSubcompactionResources();
CompactionServiceJobStatus ProcessKeyValueCompactionWithCompactionService(
SubcompactionState* sub_compact);
// update the thread status for starting a compaction.
void ReportStartedCompaction(Compaction* compaction);
Status FinishCompactionOutputFile(const Status& input_status,
SubcompactionState* sub_compact,
CompactionOutputs& outputs,
const Slice& next_table_min_key,
const Slice* comp_start_user_key,
const Slice* comp_end_user_key);
Status InstallCompactionResults(const MutableCFOptions& mutable_cf_options);
Status OpenCompactionOutputFile(SubcompactionState* sub_compact,
CompactionOutputs& outputs);
void UpdateCompactionJobStats(
const InternalStats::CompactionStats& stats) const;
void RecordDroppedKeys(const CompactionIterationStats& c_iter_stats,
CompactionJobStats* compaction_job_stats = nullptr);
void NotifyOnSubcompactionBegin(SubcompactionState* sub_compact);
void NotifyOnSubcompactionCompleted(SubcompactionState* sub_compact);
uint32_t job_id_;
// DBImpl state
const std::string& dbname_;
const std::string db_id_;
const std::string db_session_id_;
const FileOptions file_options_;
Env* env_;
std::shared_ptr<IOTracer> io_tracer_;
FileSystemPtr fs_;
// env_option optimized for compaction table reads
FileOptions file_options_for_read_;
VersionSet* versions_;
const std::atomic<bool>* shutting_down_;
const std::atomic<bool>& manual_compaction_canceled_;
FSDirectory* db_directory_;
FSDirectory* blob_output_directory_;
InstrumentedMutex* db_mutex_;
ErrorHandler* db_error_handler_;
// 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_;
// This is the earliest snapshot that could be used for write-conflict
// checking by a transaction. For any user-key newer than this snapshot, we
// should make sure not to remove evidence that a write occurred.
SequenceNumber earliest_write_conflict_snapshot_;
const SnapshotChecker* const snapshot_checker_;
JobContext* job_context_;
std::shared_ptr<Cache> table_cache_;
EventLogger* event_logger_;
bool paranoid_file_checks_;
bool measure_io_stats_;
// Stores the Slices that designate the boundaries for each subcompaction
std::vector<std::string> boundaries_;
Env::Priority thread_pri_;
std::string full_history_ts_low_;
std::string trim_ts_;
BlobFileCompletionCallback* blob_callback_;
uint64_t GetCompactionId(SubcompactionState* sub_compact) const;
// Stores the number of reserved threads in shared env_ for the number of
// extra subcompaction in kRoundRobin compaction priority
int extra_num_subcompaction_threads_reserved_;
// Stores the pointer to bg_compaction_scheduled_,
// bg_bottom_compaction_scheduled_ in DBImpl. Mutex is required when accessing
// or updating it.
int* bg_compaction_scheduled_;
int* bg_bottom_compaction_scheduled_;
// Stores the sequence number to time mapping gathered from all input files
// it also collects the smallest_seqno -> oldest_ancester_time from the SST.
SeqnoToTimeMapping seqno_time_mapping_;
// Minimal sequence number for preserving the time information. The time info
// older than this sequence number won't be preserved after the compaction and
// if it's bottommost compaction, the seq num will be zeroed out.
SequenceNumber preserve_time_min_seqno_ = kMaxSequenceNumber;
// Minimal sequence number to preclude the data from the last level. If the
// key has bigger (newer) sequence number than this, it will be precluded from
// the last level (output to penultimate level).
SequenceNumber preclude_last_level_min_seqno_ = kMaxSequenceNumber;
// Get table file name in where it's outputting to, which should also be in
// `output_directory_`.
virtual std::string GetTableFileName(uint64_t file_number);
// The rate limiter priority (io_priority) is determined dynamically here.
// The Compaction Read and Write priorities are the same for different
// scenarios, such as write stalled.
Env::IOPriority GetRateLimiterPriority();
};
// CompactionServiceInput is used the pass compaction information between two
// db instances. It contains the information needed to do a compaction. It
// doesn't contain the LSM tree information, which is passed though MANIFEST
// file.
struct CompactionServiceInput {
ColumnFamilyDescriptor column_family;
DBOptions db_options;
std::vector<SequenceNumber> snapshots;
// SST files for compaction, it should already be expended to include all the
// files needed for this compaction, for both input level files and output
// level files.
std::vector<std::string> input_files;
int output_level;
// db_id is used to generate unique id of sst on the remote compactor
std::string db_id;
// information for subcompaction
bool has_begin = false;
std::string begin;
bool has_end = false;
std::string end;
// serialization interface to read and write the object
static Status Read(const std::string& data_str, CompactionServiceInput* obj);
Status Write(std::string* output);
// Initialize a dummy ColumnFamilyDescriptor
CompactionServiceInput() : column_family("", ColumnFamilyOptions()) {}
#ifndef NDEBUG
bool TEST_Equals(CompactionServiceInput* other);
bool TEST_Equals(CompactionServiceInput* other, std::string* mismatch);
#endif // NDEBUG
};
// CompactionServiceOutputFile is the metadata for the output SST file
struct CompactionServiceOutputFile {
std::string file_name;
SequenceNumber smallest_seqno;
SequenceNumber largest_seqno;
std::string smallest_internal_key;
std::string largest_internal_key;
uint64_t oldest_ancester_time;
uint64_t file_creation_time;
uint64_t epoch_number;
uint64_t paranoid_hash;
bool marked_for_compaction;
UniqueId64x2 unique_id;
CompactionServiceOutputFile() = default;
CompactionServiceOutputFile(
const std::string& name, SequenceNumber smallest, SequenceNumber largest,
std::string _smallest_internal_key, std::string _largest_internal_key,
uint64_t _oldest_ancester_time, uint64_t _file_creation_time,
uint64_t _epoch_number, uint64_t _paranoid_hash,
bool _marked_for_compaction, UniqueId64x2 _unique_id)
: file_name(name),
smallest_seqno(smallest),
largest_seqno(largest),
smallest_internal_key(std::move(_smallest_internal_key)),
largest_internal_key(std::move(_largest_internal_key)),
oldest_ancester_time(_oldest_ancester_time),
file_creation_time(_file_creation_time),
epoch_number(_epoch_number),
paranoid_hash(_paranoid_hash),
marked_for_compaction(_marked_for_compaction),
unique_id(std::move(_unique_id)) {}
};
// CompactionServiceResult contains the compaction result from a different db
// instance, with these information, the primary db instance with write
// permission is able to install the result to the DB.
struct CompactionServiceResult {
Status status;
std::vector<CompactionServiceOutputFile> output_files;
int output_level;
// location of the output files
std::string output_path;
// some statistics about the compaction
uint64_t num_output_records = 0;
uint64_t total_bytes = 0;
uint64_t bytes_read = 0;
uint64_t bytes_written = 0;
CompactionJobStats stats;
// serialization interface to read and write the object
static Status Read(const std::string& data_str, CompactionServiceResult* obj);
Status Write(std::string* output);
#ifndef NDEBUG
bool TEST_Equals(CompactionServiceResult* other);
bool TEST_Equals(CompactionServiceResult* other, std::string* mismatch);
#endif // NDEBUG
};
// CompactionServiceCompactionJob is an read-only compaction job, it takes
// input information from `compaction_service_input` and put result information
// in `compaction_service_result`, the SST files are generated to `output_path`.
class CompactionServiceCompactionJob : private CompactionJob {
public:
CompactionServiceCompactionJob(
int job_id, Compaction* compaction, const ImmutableDBOptions& db_options,
const MutableDBOptions& mutable_db_options,
const FileOptions& file_options, VersionSet* versions,
const std::atomic<bool>* shutting_down, LogBuffer* log_buffer,
FSDirectory* output_directory, Statistics* stats,
InstrumentedMutex* db_mutex, ErrorHandler* db_error_handler,
std::vector<SequenceNumber> existing_snapshots,
std::shared_ptr<Cache> table_cache, EventLogger* event_logger,
const std::string& dbname, const std::shared_ptr<IOTracer>& io_tracer,
const std::atomic<bool>& manual_compaction_canceled,
const std::string& db_id, const std::string& db_session_id,
std::string output_path,
const CompactionServiceInput& compaction_service_input,
CompactionServiceResult* compaction_service_result);
// Run the compaction in current thread and return the result
Status Run();
void CleanupCompaction();
IOStatus io_status() const { return CompactionJob::io_status(); }
protected:
void RecordCompactionIOStats() override;
private:
// Get table file name in output_path
std::string GetTableFileName(uint64_t file_number) override;
// Specific the compaction output path, otherwise it uses default DB path
const std::string output_path_;
// Compaction job input
const CompactionServiceInput& compaction_input_;
// Compaction job result
CompactionServiceResult* compaction_result_;
};
} // namespace ROCKSDB_NAMESPACE