rocksdb/options/db_options.h
Baptiste Lemaire 4361d6d163 Add simple heuristics for experimental mempurge. (#8583)
Summary:
Add `experimental_mempurge_policy` option flag and introduce two new `MemPurge` (Memtable Garbage Collection) policies: 'ALWAYS' and 'ALTERNATE'. Default value: ALTERNATE.
`ALWAYS`: every flush will first go through a `MemPurge` process. If the output is too big to fit into a single memtable, then the mempurge is aborted and a regular flush process carries on. `ALWAYS` is designed for user that need to reduce the number of L0 SST file created to a strict minimum, and can afford a small dent in performance (possibly hits to CPU usage, read efficiency, and maximum burst write throughput).
`ALTERNATE`: a flush is transformed into a `MemPurge` except if one of the memtables being flushed is the product of a previous `MemPurge`. `ALTERNATE` is a good tradeoff between reduction in number of L0 SST files created and performance. `ALTERNATE` perform particularly well for completely random garbage ratios, or garbage ratios anywhere in (0%,50%], and even higher when there is a wild variability in garbage ratios.
This PR also includes support for `experimental_mempurge_policy` in `db_bench`.
Testing was done locally by replacing all the `MemPurge` policies of the unit tests with `ALTERNATE`, as well as local testing with `db_crashtest.py` `whitebox` and `blackbox`. Overall, if an `ALWAYS` mempurge policy passes the tests, there is no reasons why an `ALTERNATE` policy would fail, and therefore the mempurge policy was set to `ALWAYS` for all mempurge unit tests.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8583

Reviewed By: pdillinger

Differential Revision: D29888050

Pulled By: bjlemaire

fbshipit-source-id: e2cf26646d66679f6f5fb29842624615610759c1
2021-07-26 11:56:29 -07:00

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4.8 KiB
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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).
#pragma once
#include <string>
#include <vector>
#include "rocksdb/options.h"
namespace ROCKSDB_NAMESPACE {
class SystemClock;
struct ImmutableDBOptions {
static const char* kName() { return "ImmutableDBOptions"; }
ImmutableDBOptions();
explicit ImmutableDBOptions(const DBOptions& options);
void Dump(Logger* log) const;
bool create_if_missing;
bool create_missing_column_families;
bool error_if_exists;
bool paranoid_checks;
bool flush_verify_memtable_count;
bool track_and_verify_wals_in_manifest;
Env* env;
std::shared_ptr<RateLimiter> rate_limiter;
std::shared_ptr<SstFileManager> sst_file_manager;
std::shared_ptr<Logger> info_log;
InfoLogLevel info_log_level;
int max_file_opening_threads;
std::shared_ptr<Statistics> statistics;
bool use_fsync;
std::vector<DbPath> db_paths;
std::string db_log_dir;
std::string wal_dir;
size_t max_log_file_size;
size_t log_file_time_to_roll;
size_t keep_log_file_num;
size_t recycle_log_file_num;
uint64_t max_manifest_file_size;
int table_cache_numshardbits;
uint64_t WAL_ttl_seconds;
uint64_t WAL_size_limit_MB;
uint64_t max_write_batch_group_size_bytes;
size_t manifest_preallocation_size;
bool allow_mmap_reads;
bool allow_mmap_writes;
bool use_direct_reads;
bool use_direct_io_for_flush_and_compaction;
bool allow_fallocate;
bool is_fd_close_on_exec;
bool advise_random_on_open;
bool experimental_allow_mempurge;
MemPurgePolicy experimental_mempurge_policy;
size_t db_write_buffer_size;
std::shared_ptr<WriteBufferManager> write_buffer_manager;
DBOptions::AccessHint access_hint_on_compaction_start;
bool new_table_reader_for_compaction_inputs;
size_t random_access_max_buffer_size;
bool use_adaptive_mutex;
std::vector<std::shared_ptr<EventListener>> listeners;
bool enable_thread_tracking;
bool enable_pipelined_write;
bool unordered_write;
bool allow_concurrent_memtable_write;
bool enable_write_thread_adaptive_yield;
uint64_t write_thread_max_yield_usec;
uint64_t write_thread_slow_yield_usec;
bool skip_stats_update_on_db_open;
bool skip_checking_sst_file_sizes_on_db_open;
WALRecoveryMode wal_recovery_mode;
bool allow_2pc;
std::shared_ptr<Cache> row_cache;
#ifndef ROCKSDB_LITE
WalFilter* wal_filter;
#endif // ROCKSDB_LITE
bool fail_if_options_file_error;
bool dump_malloc_stats;
bool avoid_flush_during_recovery;
bool allow_ingest_behind;
bool preserve_deletes;
bool two_write_queues;
bool manual_wal_flush;
bool atomic_flush;
bool avoid_unnecessary_blocking_io;
bool persist_stats_to_disk;
bool write_dbid_to_manifest;
size_t log_readahead_size;
std::shared_ptr<FileChecksumGenFactory> file_checksum_gen_factory;
bool best_efforts_recovery;
int max_bgerror_resume_count;
uint64_t bgerror_resume_retry_interval;
bool allow_data_in_errors;
std::string db_host_id;
FileTypeSet checksum_handoff_file_types;
// Convenience/Helper objects that are not part of the base DBOptions
std::shared_ptr<FileSystem> fs;
SystemClock* clock;
Statistics* stats;
Logger* logger;
std::shared_ptr<CompactionService> compaction_service;
};
struct MutableDBOptions {
static const char* kName() { return "MutableDBOptions"; }
MutableDBOptions();
explicit MutableDBOptions(const MutableDBOptions& options) = default;
explicit MutableDBOptions(const DBOptions& options);
void Dump(Logger* log) const;
int max_background_jobs;
int base_background_compactions;
int max_background_compactions;
uint32_t max_subcompactions;
bool avoid_flush_during_shutdown;
size_t writable_file_max_buffer_size;
uint64_t delayed_write_rate;
uint64_t max_total_wal_size;
uint64_t delete_obsolete_files_period_micros;
unsigned int stats_dump_period_sec;
unsigned int stats_persist_period_sec;
size_t stats_history_buffer_size;
int max_open_files;
uint64_t bytes_per_sync;
uint64_t wal_bytes_per_sync;
bool strict_bytes_per_sync;
size_t compaction_readahead_size;
int max_background_flushes;
};
#ifndef ROCKSDB_LITE
Status GetStringFromMutableDBOptions(const ConfigOptions& config_options,
const MutableDBOptions& mutable_opts,
std::string* opt_string);
Status GetMutableDBOptionsFromStrings(
const MutableDBOptions& base_options,
const std::unordered_map<std::string, std::string>& options_map,
MutableDBOptions* new_options);
bool MutableDBOptionsAreEqual(const MutableDBOptions& this_options,
const MutableDBOptions& that_options);
#endif // ROCKSDB_LITE
} // namespace ROCKSDB_NAMESPACE