MyRocks server variables¶

The MyRocks server variables expose configuration of the underlying RocksDB engine. There several ways to set these variables:

For production deployments, you should have all variables defined in the configuration file.
Dynamic variables can be changed at runtime using the SET statement.
If you want to test things out, you can set some of the variables when starting mysqld using corresponding command-line options.

If a variable was not set in either the configuration file or as a command-line option, the default value is used.

Also, all variables can exist in one or both of the following scopes:

Global scope defines how the variable affects overall server operation.
Session scope defines how the variable affects operation for individual client connections.

Variable Name
`rocksdb_access_hint_on_compaction_start`
`rocksdb_advise_random_on_open`
`rocksdb_allow_concurrent_memtable_write`
`rocksdb_allow_to_start_after_corruption`
`rocksdb_allow_mmap_reads`
`rocksdb_allow_mmap_writes`
`rocksdb_allow_unsafe_alter`
`rocksdb_alter_column_default_inplace`
`rocksdb_alter_table_comment_inplace`
`rocksdb_base_background_compactions`
`rocksdb_blind_delete_primary_key`
`rocksdb_block_cache_numshardbits`
`rocksdb_block_cache_size`
`rocksdb_bulk_load_fail_if_not_bottommost_level`
`rocksdb_bulk_load_partial_index`
`rocksdb_bulk_load_use_sst_partitioner`
`rocksdb_block_restart_interval`
`rocksdb_block_size`
`rocksdb_block_size_deviation`
`rocksdb_bulk_load`
`rocksdb_bulk_load_allow_sk`
`rocksdb_bulk_load_allow_unsorted`
`rocksdb_bulk_load_size`
`rocksdb_bytes_per_sync`
`rocksdb_cache_dump`
`rocksdb_cache_high_pri_pool_ratio`
`rocksdb_cache_index_and_filter_blocks`
`rocksdb_cache_index_and_filter_with_high_priority`
`rocksdb_cancel_manual_compactions`
`rocksdb_charge_memory`
`rocksdb_check_iterate_bounds`
`rocksdb_checksums_pct`
`rocksdb_collect_sst_properties`
`rocksdb_column_default_value_as_expression`
`rocksdb_commit_in_the_middle`
`rocksdb_commit_time_batch_for_recovery`
`rocksdb_compact_cf`
`rocksdb_compact_lzero_now`
`rocksdb_compaction_readahead_size`
`rocksdb_compaction_sequential_deletes`
`rocksdb_compaction_sequential_deletes_count_sd`
`rocksdb_compaction_sequential_deletes_file_size`
`rocksdb_compaction_sequential_deletes_window`
`rocksdb_concurrent_prepare`
`rocksdb_converter_record_cached_length`
`rocksdb_corrupt_data_action`
`rocksdb_create_checkpoint`
`rocksdb_create_if_missing`
`rocksdb_create_missing_column_families`
`rocksdb_create_temporary_checkpoint`
`rocksdb_datadir`
`rocksdb_db_write_buffer_size`
`rocksdb_deadlock_detect`
`rocksdb_deadlock_detect_depth`
`rocksdb_debug_cardinality_multipler`
`rocksdb_debug_manual_compaction_delay`
`rocksdb_debug_optimizer_no_zero_cardinality`
`rocksdb_debug_ttl_ignore_pk`
`rocksdb_debug_ttl_read_filter_ts`
`rocksdb_debug_ttl_rec_ts`
`rocksdb_debug_ttl_snapshot_ts`
`rocksdb_default_cf_options`
`rocksdb_delayed_write_rate`
`rocksdb_delete_cf`
`rocksdb_delete_obsolete_files_period_micros`
`rocksdb_disable_file_deletions`
`rocksdb_disable_instant_ddl`
`rocksdb_enable_bulk_load_api`
`rocksdb_enable_delete_range_for_drop_index`
`rocksdb_enable_insert_with_update_caching`
`rocksdb_enable_iterate_bounds`
`rocksdb_enable_pipelined_write`
`rocksdb_enable_remove_orphaned_dropped_cfs`
`rocksdb_enable_ttl`
`rocksdb_enable_ttl_read_filtering`
`rocksdb_enable_thread_tracking`
`rocksdb_enable_write_thread_adaptive_yield`
`rocksdb_error_if_exists`
`rocksdb_error_on_suboptimal_collation`
`rocksdb_file_checksums`
`rocksdb_flush_log_at_trx_commit`
`rocksdb_flush_memtable_on_analyze`
`rocksdb_force_compute_memtable_stats`
`rocksdb_force_compute_memtable_stats_cachetime`
`rocksdb_force_flush_memtable_and_lzero_now`
`rocksdb_force_flush_memtable_now`
`rocksdb_force_index_records_in_range`
`rocksdb_hash_index_allow_collision`
`rocksdb_ignore_unknown_options`
`rocksdb_index_type`
`rocksdb_info_log_level`
`rocksdb_is_fd_close_on_exec`
`rocksdb_keep_log_file_num`
`rocksdb_large_prefix`
`rocksdb_lock_scanned_rows`
`rocksdb_lock_wait_timeout`
`rocksdb_log_file_time_to_roll`
`rocksdb_manifest_preallocation_size`
`rocksdb_manual_compaction_bottommost_level`
`rocksdb_manual_compaction_threads`
`rocksdb_manual_wal_flush`
`rocksdb_master_skip_tx_api`
`rocksdb_max_background_compactions`
`rocksdb_max_background_flushes`
`rocksdb_max_background_jobs`
`rocksdb_max_bottom_pri_background_compactions`
`rocksdb_max_compaction_history`
`rocksdb_max_file_opening_threads`
`rocksdb_max_latest_deadlocks`
`rocksdb_max_log_file_size`
`rocksdb_max_manifest_file_size`
`rocksdb_max_manual_compactions`
`rocksdb_max_open_files`
`rocksdb_max_row_locks`
`rocksdb_max_subcompactions`
`rocksdb_max_total_wal_size`
`rocksdb_merge_buf_size`
`rocksdb_merge_combine_read_size`
`rocksdb_merge_tmp_file_removal_delay_ms`
`rocksdb_new_table_reader_for_compaction_inputs`
`rocksdb_no_block_cache`
`rocksdb_no_create_column_family`
`rocksdb_override_cf_options`
`rocksdb_paranoid_checks`
`rocksdb_partial_index_ignore_killed`
`rocksdb_partial_index_sort_max_mem`
`rocksdb_pause_background_work`
`rocksdb_partial_index_blind_delete`
`rocksdb_perf_context_level`
`rocksdb_persistent_cache_path`
`rocksdb_persistent_cache_size_mb`
`rocksdb_pin_l0_filter_and_index_blocks_in_cache`
`rocksdb_print_snapshot_conflict_queries`
`rocksdb_protection_bytes_per_key`
`rocksdb_rate_limiter_bytes_per_sec`
`rocksdb_read_free_rpl`
`rocksdb_read_free_rpl_tables`
`rocksdb_records_in_range`
`rocksdb_reset_stats`
`rocksdb_rollback_on_timeout`
`rocksdb_rpl_skip_tx_api`
`rocksdb_seconds_between_stat_computes`
`rocksdb_signal_drop_index_thread`
`rocksdb_sim_cache_size`
`rocksdb_skip_bloom_filter_on_read`
`rocksdb_skip_fill_cache`
`rocksdb_skip_locks_if_skip_unique_check`
`rocksdb_sst_mgr_rate_bytes_per_sec`
`rocksdb_stats_dump_period_sec`
`rocksdb_stats_level`
`rocksdb_stats_recalc_rate`
`rocksdb_store_row_debug_checksums`
`rocksdb_strict_collation_check`
`rocksdb_strict_collation_exceptions`
`rocksdb_table_cache_numshardbits`
`rocksdb_table_stats_background_thread_nice_value`
`rocksdb_table_stats_max_num_rows_scanned`
`rocksdb_table_stats_recalc_threshold_count`
`rocksdb_table_stats_recalc_threshold_pct`
`rocksdb_table_stats_sampling_pct`
`rocksdb_table_stats_use_table_scan`
`rocksdb_tmpdir`
`rocksdb_two_write_queues`
`rocksdb_trace_block_cache_access`
`rocksdb_trace_queries`
`rocksdb_trace_sst_api`
`rocksdb_track_and_verify_wals_in_manifest`
`rocksdb_unsafe_for_binlog`
`rocksdb_update_cf_options`
`rocksdb_use_adaptive_mutex`
`rocksdb_use_default_sk_cf`
`rocksdb_use_direct_io_for_flush_and_compaction`
`rocksdb_use_direct_reads`
`rocksdb_use_fsync`
`rocksdb_use_hyper_clock_cache`
`rocksdb_use_write_buffer_manager`
`rocksdb_validate_tables`
`rocksdb_verify_row_debug_checksums`
`rocksdb_wal_bytes_per_sync`
`rocksdb_wal_dir`
`rocksdb_wal_recovery_mode`
`rocksdb_wal_size_limit_mb`
`rocksdb_wal_ttl_seconds`
`rocksdb_whole_key_filtering`
`rocksdb_write_batch_flush_threshold`
`rocksdb_write_batch_max_bytes`
`rocksdb_write_disable_wal`
`rocksdb_write_ignore_missing_column_families`
`rocksdb_write_policy`

`rocksdb_access_hint_on_compaction_start`¶

Option	Description
Command-line	–rocksdb-access-hint-on-compaction-start
Dynamic	No
Scope	Global
Data type	String or numeric
Default	NORMAL or 1

Specifies the file access pattern once a compaction is started, applied to all input files of a compaction. Possible values are:

0 = NONE
1 = NORMAL (default)
2 = SEQUENTIAL
3 = WILLNEED

`rocksdb_advise_random_on_open`¶

Option	Description
Command-line	–rocksdb-advise-random-on-open
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether to hint the underlying file system that the file access pattern is random, when a data file is opened. Enabled by default.

`rocksdb_allow_concurrent_memtable_write`¶

Option	Description
Command-line	–rocksdb-allow-concurrent-memtable-write
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to allow multiple writers to update memtables in parallel. Disabled by default.

`rocksdb_allow_to_start_after_corruption`¶

Option	Description
Command-line	–rocksdb_allow_to_start_after_corruption
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to allow server to restart once MyRocks reported data corruption. Disabled by default.

Once corruption is detected server writes marker file (named ROCKSDB_CORRUPTED) in the data directory and aborts. If marker file exists, then mysqld exits on startup with an error message. The restart failure will continue until the problem is solved or until mysqld is started with this variable turned on in the command line.

Note

Not all memtables support concurrent writes.

`rocksdb_allow_mmap_reads`¶

Option	Description
Command-line	–rocksdb-allow-mmap-reads
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to allow the OS to map a data file into memory for reads. Disabled by default. If you enable this, make sure that rocksdb_use_direct_reads is disabled.

`rocksdb_allow_mmap_writes`¶

Option	Description
Command-line	–rocksdb-allow-mmap-writes
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to allow the OS to map a data file into memory for writes. Disabled by default.

`rocksdb_allow_unsafe_alter`¶

Option	Description
Command-line	–rocksdb-allow-unsafe-alter
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Enables crash unsafe INPLACE ADD|DROP partition.

`rocksdb_alter_column_default_inplace`¶

Option	Description
Command-line	–rocksdb-alter-column-default-inplace
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

Allows an inplace alter for the ALTER COLUMN default operation.

`rocksdb_alter_table_comment_inplace`¶

Option	Description
Command-line	–rocksdb_alter_table_comment_inplace
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.33-25.

Allows changing ALTER TABLE COMMENT inplace.

This variable is disabled (OFF) by default.

`rocksdb_base_background_compactions`¶

Option	Description
Command-line	–rocksdb-base-background-compactions
Dynamic	No
Scope	Global
Data type	Numeric
Default	1

Specifies the suggested number of concurrent background compaction jobs, submitted to the default LOW priority thread pool in RocksDB. The default is 1. The allowed range of values is from -1 to 64. The maximum value depends on the rocksdb_max_background_compactions variable. This variable was replaced with rocksdb_max_background_jobs, which automatically decides how many threads to allocate toward flush/compaction.

`rocksdb_blind_delete_primary_key`¶

Option	Description
Command-line	–rocksdb-blind-delete-primary-key
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.20-11. Skips verifying if rows exists before executing deletes. The following conditions must be met:

The variable is enabled
Only a single table listed in the DELETE statement
The table has only a primary key with no secondary keys

`rocksdb_block_cache_numshardbits`¶

Option	Description
Command-line	–rocksdb-block-cache-numshardbits
Dynamic	No
Scope	Global
Data type	Numeric
Default	-1

This variable has been implemented in Percona Server for MySQL 8.0.36-28.

This variable specifies the number of shards ,numShardBits, for the block cache in RocksDB. The cache is sharded into 2^numShardBits shards by the key hash.

The default value is -1. The -1 value means that RocksDB automatically determines the number of shards for the block cache based on the cache capacity.

The minimum value is -1 and the maximum value is 8.

`rocksdb_block_cache_size`¶

Option	Description
Command-line	–rocksdb-block-cache-size
Dynamic	No
Scope	Global
Data type	Numeric
Default	536870912

Specifies the size of the LRU block cache for RocksDB. This memory is reserved for the block cache, which is in addition to any filesystem caching that may occur.

Minimum value is 1024, because that’s the size of one block.

Default value is 536870912.

Maximum value is 9223372036854775807.

`rocksdb_bulk_load_fail_if_not_bottommost_level`¶

Option	Description
Command-line	–rocksdb_bulk_load_fail_if_not_bottommost_level
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.33-25.

When this variable is enabled, the bulk load fails if an sst file created during bulk load cannot be placed to the bottommost level in the rocksdb.

This variable can be enabled or disabled only when the rocksdb_bulk_load is OFF.

This variable is disabled (OFF) by default.

Warning

When rocksdb_bulk_load_fail_if_not_bottommost_level is disabled, it may cause severe performance impact.

`rocksdb_block_restart_interval`¶

Option	Description
Command-line	–rocksdb-block-restart-interval
Dynamic	No
Scope	Global
Data type	Numeric
Default	16

Specifies the number of keys for each set of delta encoded data. Default value is 16. Allowed range is from 1 to 2147483647.

`rocksdb_block_size`¶

Option	Description
Command-line	–rocksdb-block-size
Dynamic	No
Scope	Global
Data type	Numeric
Default	16 KB

Specifies the size of the data block for reading RocksDB data files. The default value is 16 KB. The allowed range is from 1024 to 18446744073709551615 bytes.

`rocksdb_block_size_deviation`¶

Option	Description
Command-line	–rocksdb-block-size-deviation
Dynamic	No
Scope	Global
Data type	Numeric
Default	10

Specifies the threshold for free space allowed in a data block (see rocksdb_block_size). If there is less space remaining, close the block (and write to new block). Default value is 10, meaning that the block is not closed until there is less than 10 bits of free space remaining.

Allowed range is from 1 to 2147483647.

`rocksdb_bulk_load_allow_sk`¶

Option	Description
Command-line	–rocksdb-bulk-load-allow-sk
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Enabling this variable allows secondary keys to be added using the bulk loading feature. This variable can be enabled or disabled only when the rocksdb_bulk_load is OFF.

`rocksdb_bulk_load_allow_unsorted`¶

Option	Description
Command-line	–rocksdb-bulk-load-allow-unsorted
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

By default, the bulk loader requires its input to be sorted in the primary key order. If enabled, unsorted inputs are allowed too, which are then sorted by the bulkloader itself, at a performance penalty.

`rocksdb_bulk_load`¶

Option	Description
Command-line	–rocksdb-bulk-load
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Specifies whether to use bulk load: MyRocks will ignore checking keys for uniqueness or acquiring locks during transactions. Disabled by default. Enable this only if you are certain that there are no row conflicts, for example, when setting up a new MyRocks instance from a MySQL dump.

When the rocksdb_bulk_load variable is enabled, it behaves as if the variable rocksdb_commit_in_the_middle is enabled, even if the variable rocksdb_commit_in_the_middle is disabled.

`rocksdb_bulk_load_partial_index`¶

Option	Description
Command-line	–rocksdb-bulk-load-partial-index
Dynamic	Yes
Scope	Local
Data type	Boolean
Default	ON

The variable was implemented in Percona Server for MySQL 8.0.27-18. Materializes partial index during bulk load instead of leaving the index empty.

`rocksdb_bulk_load_use_sst_partitioner`¶

Option	Description
Command-line	–rocksdb_bulk_load_use_sst_partitioner
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.33-25.

If enabled, this variable uses sst partitioner to split sst files to ensure bulk load sst files can be ingested to bottommost level.

This variable is disabled (OFF) by default.

`rocksdb_bulk_load_size`¶

Option	Description
Command-line	–rocksdb-bulk-load-size
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	1000

Specifies the number of keys to accumulate before committing them to the storage engine when bulk load is enabled (see rocksdb_bulk_load). Default value is 1000, which means that a batch can contain up to 1000 records before they are implicitly committed. Allowed range is from 1 to 1073741824.

`rocksdb_bytes_per_sync`¶

Option	Description
Command-line	–rocksdb-bytes-per-sync
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

Specifies how often should the OS sync files to disk as they are being written, asynchronously, in the background. This operation can be used to smooth out write I/O over time. Default value is 0 meaning that files are never synced. Allowed range is up to 18446744073709551615.

`rocksdb_cache_dump`¶

Option	Description
Command-line	–rocksdb-cache-dump
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

The variable was implemented in Percona Server for MySQL 8.0.20-11. Includes RocksDB block cache content in core dump. This variable is enabled by default.

`rocksdb_cache_high_pri_pool_ratio`¶

Option	Description
Command-line	–rocksdb-cache-high-pri-pool-ratio
Dynamic	No
Scope	Global
Data type	Double
Default	0.0

This variable specifies the size of the block cache high-pri pool. The default value and minimum value is 0.0. The maximum value is 1.0.

`rocksdb_cache_index_and_filter_blocks`¶

Option	Description
Command-line	–rocksdb-cache-index-and-filter-blocks
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether RocksDB should use the block cache for caching the index and bloomfilter data blocks from each data file. Enabled by default. If you disable this feature, RocksDB allocates additional memory to maintain these data blocks.

`rocksdb_cache_index_and_filter_with_high_priority`¶

Option	Description
Command-line	–rocksdb-cache-index-and-filter-with-high-priority
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether RocksDB should use the block cache with high priority for caching the index and bloomfilter data blocks from each data file. Enabled by default. If you disable this feature, RocksDB allocates additional memory to maintain these data blocks.

`rocksdb_cancel_manual_compactions`¶

Option	Description
Command-line	–rocksdb-cancel-manual-compactions
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.27-18. Cancels all ongoing manual compactions.

`rocksdb_charge_memory`¶

Option	Description
Command-line	–rocksdb_charge_memory
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.33-25.

This variable is tech preview and may be removed in the future releases.

Turns on RocksDB memory-charging related features (BlockBasedTableOptions::cache_usage_options.options.charged) from cnf files. This variable is related to rocksdb_use_write_buffer_manager.

This variable is disabled (OFF) by default.

`rocksdb_check_iterate_bounds`¶

Option	Description
Command-line	–rocksdb-check-iterate-bounds
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	ON

This variable has been implemented in Percona Server for MySQL 8.0.36-28.

This variable enables checking the upper and lower bounds of the RocksDB iterator during iteration. The default value in ON which means this variable is enabled.

`rocksdb_checksums_pct`¶

Option	Description
Command-line	–rocksdb-checksums-pct
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	100

Specifies the percentage of rows to be checksummed. Default value is 100 (checksum all rows). Allowed range is from 0 to 100.

`rocksdb_collect_sst_properties`¶

Option	Description
Command-line	–rocksdb-collect-sst-properties
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether to collect statistics on each data file to improve optimizer behavior. Enabled by default.

`rocksdb_column_default_value_as_expression`¶

Option	Description
Command-line	–rocksdb_column_default_value_as_expression
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

The variable was implemented in Percona Server for MySQL 8.0.33-25.

Allows to set a function as the default value for a column.

This variable is enabled (ON) by default.

`rocksdb_commit_in_the_middle`¶

Option	Description
Command-line	–rocksdb-commit-in-the-middle
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to commit rows implicitly when a batch contains more than the value of rocksdb_bulk_load_size.

This option should only be enabled at the time of data import because it may cause locking errors.

This variable is disabled by default. When the rocksdb_bulk_load variable is enabled, it behaves as if the variable rocksdb_commit_in_the_middle is enabled, even if the variable rocksdb_commit_in_the_middle is disabled.

`rocksdb_commit_time_batch_for_recovery`¶

Option	Description
Command-line	–rocksdb-commit-time-batch-for-recovery
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Specifies whether to write the commit time write batch into the database or not.

Note

If the commit time write batch is only useful for recovery, then writing to WAL is enough.

`rocksdb_compact_cf`¶

Option	Description
Command-line	–rocksdb-compact-cf
Dynamic	Yes
Scope	Global
Data type	String
Default

Specifies the name of the column family to compact.

`rocksdb_compact_lzero_now`¶

Option	Description
Command-line	–rocksdb-compact-lzero-now
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

This variable has been implemented in Percona Server for MySQL 8.0.36-28.

This variable acts as a trigger. Set the variable to ON, rocksdb-compact-lzero-now=ON, to immediately compact all the Level 0 (L0) files. After all the L0 files are compacted, the variable value automatically switches to OFF.

`rocksdb_compaction_readahead_size`¶

Option	Description
Command-line	–rocksdb-compaction-readahead-size
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

Specifies the size of reads to perform ahead of compaction. Default value is 0. Set this to at least 2 megabytes (16777216) when using MyRocks with spinning disks to ensure sequential reads instead of random. Maximum allowed value is 18446744073709551615.

Note

If you set this variable to a non-zero value, rocksdb_new_table_reader_for_compaction_inputs is enabled.

`rocksdb_compaction_sequential_deletes`¶

Option	Description
Command-line	–rocksdb-compaction-sequential-deletes
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	149999

Note

In version Percona Server for MySQL 8.0.36-28 and later, the default value is changed from 0 to 149999.

Specifies the threshold to trigger compaction on a file if it has more than this number of sequential delete markers.

The default value is 149999.

Maximum allowed value is 2000000 (two million delete markers).

Note

Depending on workload patterns, MyRocks can potentially maintain large numbers of delete markers, which increases latency of queries. This compaction feature will reduce latency, but may also increase the MyRocks write rate. Use this variable together with rocksdb_compaction_sequential_deletes_file_size to only perform compaction on large files.

`rocksdb_compaction_sequential_deletes_count_sd`¶

Option	Description
Command-line	–rocksdb-compaction-sequential-deletes-count-sd
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

Note

In version Percona Server for MySQL 8.0.36-28 and later, the default value is changed from OFF to ON.

Specifies whether to count single deletes as delete markers recognized by rocksdb_compaction_sequential_deletes.

The default value is ON which means the variable is enabled.

`rocksdb_compaction_sequential_deletes_file_size`¶

Option	Description
Command-line	–rocksdb-compaction-sequential-deletes-file-size
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

Specifies the minimum file size required to trigger compaction on it by rocksdb_compaction_sequential_deletes. Default value is 0, meaning that compaction is triggered regardless of file size. Allowed range is from -1 to 9223372036854775807.

`rocksdb_compaction_sequential_deletes_window`¶

Option	Description
Command-line	–rocksdb-compaction-sequential-deletes-window
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	150000

Note

In version Percona Server for MySQL 8.0.36-28 and later, the default value is changed from 0 to 150000.

Specifies the size of the window for counting delete markers by rocksdb_compaction_sequential_deletes. Default value is 150000. Allowed range is up to 2000000 (two million).

`rocksdb_concurrent_prepare`¶

Option	Description
Command-line	–rocksdb-concurrent_prepare
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

When enabled this variable allows/encourages threads that are using two-phase commit to prepare in parallel. This variable was renamed in upstream to rocksdb_two_write_queues.

`rocksdb_corrupt_data_action`¶

Option	Description
Command-line	–rocksdb_corrupt_data_action
Dynamic	Yes
Scope	Global
Data type	enum { ERROR = 0, ABORT_SERVER, WARNING };
Default	ERROR

The variable was implemented in Percona Server for MySQL 8.0.33-25.

This variable controls the behavior when hitting the data corruption in MyRocks.

You can select one of the following actions:

ERROR - fail the query with the error HA_ERR_ROCKSDB_CORRUPT_DATA
ABORT_SERVER - crash the server
WARNING - pass the query with warning

The default value is ERROR that means the query fails with the error HA_ERR_ROCKSDB_CORRUPT_DATA.

`rocksdb_converter_record_cached_length`¶

Option	Description
Command-line	–rocksdb_converter_record_cached_length
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

The variable was implemented in Percona Server for MySQL 8.0.33-25.

Specifies the maximum number of bytes to cache on table handler for encoding table record data.

If the used memory exceeds rocksdb_converter_record_cached_length, the memory is released when the handler is returned to the table handler cache.

The minimum value is 0 (zero) that means there is no limit. The maximum value is UINT64_MAX (0xffffffffffffffff).

The default value is 0(zero) that means there is no limit.

`rocksdb_create_checkpoint`¶

Option	Description
Command-line	–rocksdb-create-checkpoint
Dynamic	Yes
Scope	Global
Data type	String
Default

Specifies the directory where MyRocks should create a checkpoint. Empty by default.

`rocksdb_create_if_missing`¶

Option	Description
Command-line	–rocksdb-create-if-missing
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether MyRocks should create its database if it does not exist. Enabled by default.

`rocksdb_create_missing_column_families`¶

Option	Description
Command-line	–rocksdb-create-missing-column-families
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether MyRocks should create new column families if they do not exist. Disabled by default.

`rocksdb_create_temporary_checkpoint`¶

Option	Description
Command-line	–rocksdb-create-temporary-checkpoint
Dynamic	Yes
Scope	Session
Data type	String

This variable has been implemented in Percona Server for MySQL 8.0.15-6. When specified it will create a temporary RocksDB ‘checkpoint’ or ‘snapshot’ in the datadir. If the session ends with an existing checkpoint, or if the variable is reset to another value, the checkpoint will get removed. This variable should be used by backup tools. Prolonged use or other misuse can have serious side effects to the server instance.

`rocksdb_datadir`¶

Option	Description
Command-line	–rocksdb-datadir
Dynamic	No
Scope	Global
Data type	String
Default	`./.rocksdb`

Specifies the location of the MyRocks data directory. By default, it is created in the current working directory.

`rocksdb_db_write_buffer_size`¶

Option	Description
Command-line	–rocksdb-db-write-buffer-size
Dynamic	No
Scope	Global
Data type	Numeric
Default	0

Specifies the maximum size of all memtables used to store writes in MyRocks across all column families. When this size is reached, the data is flushed to persistent media. The default value is 0. The allowed range is up to 18446744073709551615.

`rocksdb_deadlock_detect`¶

Option	Description
Command-line	–rocksdb-deadlock-detect
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Specifies whether MyRocks should detect deadlocks. Disabled by default.

`rocksdb_deadlock_detect_depth`¶

Option	Description
Command-line	–rocksdb-deadlock-detect-depth
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	50

Specifies the number of transactions deadlock detection will traverse through before assuming deadlock.

`rocksdb_debug_cardinality_multiplier`¶

Option	Description
Command-line	–rocksdb-debug-cardinality-multiplier
Dynamic	Yes
Scope	Global
Data type	UINT
Default	2

The cardinality multiplier used in tests. The minimum value is 0. The maxium value is 2147483647 (INT_MAX).

`rocksdb_debug_manual_compaction_delay`¶

Option	Description
Command-line	–rocksdb-debug-manual-compaction-delay
Dynamic	Yes
Scope	Global
Data type	UINT
Default	0

Only use this variable when debugging.

This variable specifies a sleep, in seconds, to simulate long-running compactions. The minimum value is 0. The maximum value is 4292967295 (UINT_MAX).

`rocksdb_debug_optimizer_no_zero_cardinality`¶

Option	Description
Command-line	–rocksdb-debug-optimizer-no-zero-cardinality
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

Specifies whether MyRocks should prevent zero cardinality by always overriding it with some value.

`rocksdb_debug_ttl_ignore_pk`¶

Option	Description
Command-line	–rocksdb-debug-ttl-ignore-pk
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

For debugging purposes only. If true, compaction filtering will not occur on Primary Key TTL data. This variable is a no-op in non-debug builds.

`rocksdb_debug_ttl_read_filter_ts`¶

Option	Description
Command-line	–rocksdb_debug-ttl-read-filter-ts
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

For debugging purposes only. Overrides the TTL read filtering time to time + debug_ttl_read_filter_ts. A value of 0 denotes that the variable is not set. This variable is a no-op in non-debug builds.

`rocksdb_debug_ttl_rec_ts`¶

Option	Description
Command-line	–rocksdb-debug-ttl-rec-ts
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

For debugging purposes only. Overrides the TTL of records to now() + debug_ttl_rec_ts. The value can be ± to simulate a record inserted in the past vs a record inserted in the future . A value of 0 denotes that the variable is not set. This variable is a no-op in non-debug builds.

`rocksdb_debug_ttl_snapshot_ts`¶

Option	Description
Command-line	–rocksdb-debug-ttl-snapshot-ts
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

For debugging purposes only. Sets the snapshot during compaction to now() + rocksdb_debug_set_ttl_snapshot_ts.

The value can be ± to simulate a snapshot in the past vs a snapshot created in the future . A value of 0 denotes that the variable is not set. This variable is a no-op in non-debug builds.

`rocksdb_default_cf_options`¶

Option	Description
Command-line	–rocksdb-default-cf-options
Dynamic	No
Scope	Global
Data type	String

The dafault value is:

block_based_table_factory= {cache_index_and_filter_blocks=1;filter_policy=bloomfilter:10:false;whole_key_filtering=1};level_compaction_dynamic_level_bytes=true;optimize_filters_for_hits=true;compaction_pri=kMinOverlappingRatio;compression=kLZ4Compression;bottommost_compression=kLZ4Compression;

Specifies the default column family options for MyRocks. On startup, the server applies this option to all existing column families. This option is read-only at runtime.

`rocksdb_delayed_write_rate`¶

Option	Description
Command-line	–rocksdb-delayed-write-rate
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	16777216

Specifies the write rate in bytes per second, which should be used if MyRocks hits a soft limit or threshold for writes. Default value is 16777216 (16 MB/sec). Allowed range is from 0 to 18446744073709551615.

`rocksdb_delete_cf`¶

Option	Description
Command-line	–rocksdb-delete-cf
Dynamic	Yes
Scope	Global
Data type	String
Default	“”

The variable was implemented in Percona Server for MySQL 8.0.20-11. Deletes the column family by name. The default value is “” , an empty string.

For example:

SET @@global.ROCKSDB_DELETE_CF = 'cf_primary_key';

`rocksdb_delete_obsolete_files_period_micros`¶

Option	Description
Command-line	–rocksdb-delete-obsolete-files-period-micros
Dynamic	No
Scope	Global
Data type	Numeric
Default	21600000000

Specifies the period in microseconds to delete obsolete files regardless of files removed during compaction. Default value is 21600000000 (6 hours). Allowed range is up to 9223372036854775807.

`rocksdb_disable_file_deletions`¶

Option	Description
Command-line	–rocksdb-disable-file-deletions
Dynamic	Yes
Scope	Session
Data type	Boolean
Default	OFF

This variable has been implemented in Percona Server for MySQL 8.0.15-6. It allows a client to temporarily disable RocksDB deletion of old WAL and .sst files for the purposes of making a consistent backup. If the client session terminates for any reason after disabling deletions and has not re-enabled deletions, they will be explicitly re-enabled. This variable should be used by backup tools. Prolonged use or other misuse can have serious side effects to the server instance.

`rocksdb_disable_instant_ddl`¶

Option	Description
Command-line	–rocksdb_disable_instant_ddl
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

The variable was implemented in Percona Server for MySQL 8.0.33-25.

Disables instant DDL during ALTER TABLE operations.

This variable is enabled (ON) by default.

`rocksdb_enable_bulk_load_api`¶

Option	Description
Command-line	–rocksdb-enable-bulk-load-api
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether to use the SSTFileWriter feature for bulk loading, This feature bypasses the memtable, but requires keys to be inserted into the table in either ascending or descending order. Enabled by default. If disabled, bulk loading uses the normal write path via the memtable and does not require keys to be inserted in any order.

`rocksdb_enable_delete_range_for_drop_index`¶

Option	Description
Command-line	–rocksdb_enable_delete_range_for_drop_index
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.33-25.

Enables drop table / index by calling the DeleteRange.

This option is disabled (OFF) by default.

`rocksdb_enable_insert_with_update_caching`¶

Option	Description
Command-line	–rocksdb-enable-insert-with-update-caching
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

The variable was implemented in Percona Server for MySQL 8.0.20-11. Specifies whether to enable optimization where the read is cached from a failed insertion attempt in INSERT ON DUPLICATE KEY UPDATE.

`rocksdb_enable_iterate_bounds`¶

Option	Description
Command-line	–rocksdb-enable-iterate-bounds
Dynamic	Yes
Scope	Global, Local
Data type	Boolean
Default	ON

The variable was implemented in Percona Server for MySQL 8.0.20-11. Enables the rocksdb iterator upper bounds and lower bounds in read options.

`rocksdb_enable_pipelined_write`¶

Option	Description
Command-line	–rocksdb-enable-pipelined-write
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.25-15.

DBOptions::enable_pipelined_write for RocksDB.

If enable_pipelined_write is ON, a separate write thread is maintained for WAL write and memtable write. A write thread first enters the WAL writer queue and then the memtable writer queue. A pending thread on the WAL writer queue only waits for the previous WAL write operations but does not wait for memtable write operations. Enabling the feature may improve write throughput and reduce latency of the prepare phase of a two-phase commit.

`rocksdb_enable_remove_orphaned_dropped_cfs`¶

Option	Description
Command-line	–rocksdb-enable-remove-orphaned-dropped-cfs
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

The variable was implemented in Percona Server for MySQL 8.0.20-11. Enables the removal of dropped column families (cfs) from metadata if the cfs do not exist in the cf manager.

The default value is ON.

`rocksdb_enable_ttl`¶

Option	Description
Command-line	–rocksdb-enable-ttl
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

By default, this variable removes expired Time-to-Live (TTL) records during compaction. TTL records are entries in the database that are automatically set to expire after a specified period of time and can be deleted during the compaction process.

Set this variable to OFF to keep expired TTL records during compaction.

`rocksdb_enable_ttl_read_filtering`¶

Option	Description
Command-line	–rocksdb-enable-ttl-read-filtering
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

For tables with TTL, expired records are skipped/filtered out during processing and in query results.

Disabling this option allows these records to be seen, but the rows may disappear during transactions since they are deleted during compaction. Use with caution.

`rocksdb_enable_thread_tracking`¶

Option	Description
Command-line	–rocksdb-enable-thread-tracking
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to enable tracking the status of threads accessing the database. Disabled by default. If enabled, thread status will be available via GetThreadList().

`rocksdb_enable_write_thread_adaptive_yield`¶

Option	Description
Command-line	–rocksdb-enable-write-thread-adaptive-yield
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether the MyRocks write batch group leader should wait up to the maximum allowed time before blocking on a mutex. Disabled by default. Enable it to increase throughput for concurrent workloads.

`rocksdb_error_if_exists`¶

Option	Description
Command-line	–rocksdb-error-if-exists
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to report an error when a database already exists. Disabled by default.

`rocksdb_error_on_suboptimal_collation`¶

Option	Description
Command-line	–rocksdb-error-on-suboptimal-collation
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether to report an error instead of a warning if an index is created on a char field where the table has a sub-optimal collation (case insensitive). Enabled by default.

`rocksdb_file_checksums`¶

Option	Description
Command-line	–rocksdb-file-checksums
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

This variable has been implemented in Percona Server for MySQL 8.0.36-28.

This variable controls whether to write and check RocksDB file-level checksums. The default value is OFF which means the variable is disabled.

`rocksdb_flush_log_at_trx_commit`¶

Option	Description
Command-line	–rocksdb-flush-log-at-trx-commit
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	1

Specifies whether to sync on every transaction commit, similar to innodb_flush_log_at_trx_commit. Enabled by default, which ensures ACID compliance.

Possible values:

0: Do not sync on transaction commit. This provides better performance, but may lead to data inconsistency in case of a crash.
1: Sync on every transaction commit. This is set by default and recommended as it ensures data consistency, but reduces performance.
2: Sync every second.

`rocksdb_flush_memtable_on_analyze`¶

Option	Description
Command-line	–rocksdb-flush-memtable-on-analyze
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	ON

Specifies whether to flush the memtable when running ANALYZE on a table. Enabled by default. This ensures accurate cardinality by including data in the memtable for calculating stats.

`rocksdb_force_compute_memtable_stats`¶

Option	Description
Command-line	–rocksdb-force-compute-memtable-stats
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

Specifies whether data in the memtables should be included for calculating index statistics used by the query optimizer. Enabled by default. This provides better accuracy, but may reduce performance.

`rocksdb_force_compute_memtable_stats_cachetime`¶

Option	Description
Command-line	–rocksdb-force-compute-memtable-stats-cachetime
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	60000000

Specifies for how long the cached value of memtable statistics should be used instead of computing it every time during the query plan analysis.

`rocksdb_force_flush_memtable_and_lzero_now`¶

Option	Description
Command-line	–rocksdb-force-flush-memtable-and-lzero-now
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Works similar to rocksdb_force_flush_memtable_now but also flushes all L0 files.

`rocksdb_force_flush_memtable_now`¶

Option	Description
Command-line	–rocksdb-force-flush-memtable-now
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Note

In version Percona Server for MySQL 8.0.36-28 and later, the default value is changed from ON to OFF.

This variable acts as a trigger. Set the variable to ON, rocksdb_force_flush_memtable_now=ON, to immediately flush all memtables. After all memtables are flushed, the variable value automatically switches to OFF.

Warning

Use with caution! Write requests will be blocked until all memtables are flushed.

`rocksdb_force_index_records_in_range`¶

Option	Description
Command-line	–rocksdb-force-index-records-in-range
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	1

Specifies the value used to override the number of rows returned to query optimizer when FORCE INDEX is used. Default value is 1. Allowed range is from 0 to 2147483647. Set to 0 if you do not want to override the returned value.

`rocksdb_hash_index_allow_collision`¶

Option	Description
Command-line	–rocksdb-hash-index-allow-collision
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether hash collisions are allowed. Enabled by default, which uses less memory. If disabled, full prefix is stored to prevent hash collisions.

`rocksdb_ignore_unknown_options`¶

Option	Description
Command-line
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

When enabled, it allows RocksDB to receive unknown options and not exit.

`rocksdb_index_type`¶

Option	Description
Command-line	–rocksdb-index-type
Dynamic	No
Scope	Global
Data type	Enum
Default	kBinarySearch

Specifies the type of indexing used by MyRocks:

kBinarySearch: Binary search (default).
kHashSearch: Hash search.

`rocksdb_info_log_level`¶

Option	Description
Command-line	–rocksdb-info-log-level
Dynamic	Yes
Scope	Global
Data type	Enum
Default	error_level

Specifies the level for filtering messages written by MyRocks to the mysqld log.

debug_level: Maximum logging (everything including debugging log messages)
info_level
warn_level
error_level (default)
fatal_level: Minimum logging (only fatal error messages logged)

`rocksdb_is_fd_close_on_exec`¶

Option	Description
Command-line	–rocksdb-is-fd-close-on-exec
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether child processes should inherit open file jandles. Enabled by default.

`rocksdb_large_prefix`¶

Option	Description
Command-line	–rocksdb-large-prefix
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

This variable is deprecated in Percona Server for MySQL 8.0.36-28 and will be removed in a future release.

When enabled, this option allows index key prefixes longer than 767 bytes (up to 3072 bytes). The values for rocksdb_large_prefix should be the same between source and replica.

Note

In version Percona Server for MySQL 8.0.16-7 and later, the default value is changed to ON.

`rocksdb_keep_log_file_num`¶

Option	Description
Command-line	–rocksdb-keep-log-file-num
Dynamic	No
Scope	Global
Data type	Numeric
Default	1000

Specifies the maximum number of info log files to keep. Default value is 1000. Allowed range is from 1 to 18446744073709551615.

`rocksdb_lock_scanned_rows`¶

Option	Description
Command-line	–rocksdb-lock-scanned-rows
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Specifies whether to hold the lock on rows that are scanned during UPDATE and not actually updated. Disabled by default.

`rocksdb_lock_wait_timeout`¶

Option	Description
Command-line	–rocksdb-lock-wait-timeout
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	1

Specifies the number of seconds MyRocks should wait to acquire a row lock before aborting the request. Default value is 1. Allowed range is up to 1073741824.

`rocksdb_log_file_time_to_roll`¶

Option	Description
Command-line	–rocksdb-log-file-time-to-roll
Dynamic	No
Scope	Global
Data type	Numeric
Default	0

Specifies the period (in seconds) for rotating the info log files. Default value is 0, meaning that the log file is not rotated. Allowed range is up to 18446744073709551615.

`rocksdb_manifest_preallocation_size`¶

Option	Description
Command-line	–rocksdb-manifest-preallocation-size
Dynamic	No
Scope	Global
Data type	Numeric
Default	0

Specifies the number of bytes to preallocate for the MANIFEST file used by MyRocks to store information about column families, levels, active files, etc. Default value is 0. Allowed range is up to 18446744073709551615.

Note

A value of 4194304 (4 MB) is reasonable to reduce random I/O on XFS.

`rocksdb_manual_compaction_bottommost_level`¶

Option	Description
Command-line	–rocksdb-manual-compaction-bottommost-level
Dynamic	Yes
Scope	Local
Data type	Enum
Default	kForceOptimized

Option for bottommost level compaction during manual compaction:

kSkip - Skip bottommost level compaction
kIfHaveCompactionFilter - Only compact bottommost level if there is a compaction filter
kForce - Always compact bottommost level
kForceOptimized - Always compact bottommost level but in bottommost level avoid double-compacting files created in the same compaction

rocksdb_manual_compaction_threads¶

Option	Description
Command-line	–rocksdb-manual-compaction-threads
Dynamic	Yes
Scope	Local
Data type	INT
Default	0

The variable defines the number of RocksDB threads to run for a manual compaction. The minimum value is 0. The maximum value is 120.

`rocksdb_manual_wal_flush`¶

Option	Description
Command-line	–rocksdb-manual-wal-flush
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

This variable can be used to disable automatic/timed WAL flushing and instead rely on the application to do the flushing.

`rocksdb_master_skip_tx_api`¶

Option	Description
Command-line
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.20-11. When enabled, uses the WriteBatch API, which is faster. The session does not hold any lock on row access. This variable is not effective on replica.

Note

Due to the disabled row locks, improper use of the variable can cause data corruption or inconsistency.

`rocksdb_max_background_compactions`¶

Option	Description
Command-line	–rocksdb-max-background-compactions
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	-1

The variable was implemented in Percona Server for MySQL 8.0.20-11.

Sets DBOptions:: max_background_compactions for RocksDB. The default value is -1 The allowed range is -1 to 64. This variable was replaced by rocksdb_max_background_jobs, which automatically decides how many threads to allocate towards flush/compaction. This variable was re-implemented in Percona Server for MySQL 8.0.20-11.

`rocksdb_max_background_flushes`¶

Option	Description
Command-line	–rocksdb-max-background-flushes
Dynamic	No
Scope	Global
Data type	Numeric
Default	-1

The variable was implemented in Percona Server for MySQL 8.0.20-11.

Sets DBOptions:: max_background_flushes for RocksDB. The default value is -1. The allowed range is -1 to 64. This variable has been replaced by rocksdb_max_background_jobs, which automatically decides how many threads to allocate towards flush/compaction.

`rocksdb_max_background_jobs`¶

Option	Description
Command-line	–rocksdb-max-background-jobs
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	2

This variable replaced rocksdb_base_background_compactions, rocksdb_max_background_compactions, and rocksdb_max_background_flushes variables. This variable specifies the maximum number of background jobs. It automatically decides how many threads to allocate towards flush/compaction. It was implemented to reduce the number of (confusing) options users and can tweak and push the responsibility down to RocksDB level.

`rocksdb_max_bottom_pri_background_compactions`¶

Option	Description
Command-line	–rocksdb_max_bottom_pri_background_compactions
Dynamic	No
Data type	Unsigned integer
Default	0

The variable was implemented in Percona Server for MySQL 8.0.20-11. Creates a specified number of threads, sets a lower CPU priority, and letting compactions use them. The maximum compaction concurrency is capped by rocksdb_max_background_compactions or rocksdb_max_background_jobs

The minimum value is 0 and the maximum value is 64.

`rocksdb_max_compaction_history`¶

Option	Description
Command-line	–rocksdb-max-compaction-history
Dynamic	Yes
Scope	Global
Data type	Unsigned integer
Default	64

The minimum value is 0 and the maximum value is UINT64_MAX.

Tracks the history for at most rockdb_mx_compaction_history completed compactions. The history is in the INFORMATION_SCHEMA.ROCKSDB_COMPACTION_HISTORY table.

`rocksdb_max_file_opening_threads`¶

Option	Description
Command-line	–rocksdb-max-file-opening-threads
Dynamic	No
Scope	Global
Data type	Numeric
Default	16

This variable has been implemented in Percona Server for MySQL 8.0.36-28.

This variable sets DBOptions::max_file_opening_threads for RocksDB. The default value is 16. The minimum value is 1 and the maximum value is 2147483647 (INT_MAX).

`rocksdb_max_latest_deadlocks`¶

Option	Description
Command-line	–rocksdb-max-latest-deadlocks
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	5

Specifies the maximum number of recent deadlocks to store.

`rocksdb_max_log_file_size`¶

Option	Description
Command-line	–rocksdb-max-log-file-size
Dynamic	No
Scope	Global
Data type	Numeric
Default	0

Specifies the maximum size for info log files, after which the log is rotated. Default value is 0, meaning that only one log file is used. Allowed range is up to 18446744073709551615.

Also see rocksdb_log_file_time_to_roll.

`rocksdb_max_manifest_file_size`¶

Option	Description
Command-line	–rocksdb-manifest-log-file-size
Dynamic	No
Scope	Global
Data type	Numeric
Default	18446744073709551615

Specifies the maximum size of the MANIFEST data file, after which it is rotated. Default value is also the maximum, making it practically unlimited: only one manifest file is used.

`rocksdb_max_manual_compactions`¶

Option	Description
Command-line	–rocksdb-max-manual-compactions
Dynamic	Yes
Scope	Global
Data type	UINT
Default	10

The variable defines the maximum number of pending plus ongoing manual compactions. The default value and the minimum value is 0. The maximum value is 4294967295 (UNIT_MAX).

`rocksdb_max_open_files`¶

Option	Description
Command-line	–rocksdb-max-open-files
Dynamic	No
Scope	Global
Data type	Numeric
Default	1000

Specifies the maximum number of file handles opened by MyRocks. Values in the range between 0 and open_files_limit are taken as they are. If rocksdb_max_open_files value is greater than open_files_limit, it will be reset to ½ of open_files_limit, and a warning will be emitted to the mysqld error log. A value of -2 denotes auto tuning: just sets rocksdb_max_open_files value to ½ of open_files_limit. Finally, -1 means no limit, i.e. an infinite number of file handles.

Warning

Setting rocksdb_max_open_files to -1 is dangerous, as the server may quickly run out of file handles in this case.

`rocksdb_max_row_locks`¶

Option	Description
Command-line	–rocksdb-max-row-locks
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	1048576

Specifies the limit on the maximum number of row locks a transaction can have before it fails. Default value is also the maximum, making it practically unlimited: transactions never fail due to row locks.

`rocksdb_max_subcompactions`¶

Option	Description
Command-line	–rocksdb-max-subcompactions
Dynamic	No
Scope	Global
Data type	Numeric
Default	1

Specifies the maximum number of threads allowed for each compaction job. Default value of 1 means no subcompactions (one thread per compaction job). Allowed range is up to 64.

`rocksdb_max_total_wal_size`¶

Option	Description
Command-line	–rocksdb-max-total-wal-size
Dynamic	No
Scope	Global
Data type	Numeric
Default	2 GB

Specifies the maximum total size of WAL (write-ahead log) files, after which memtables are flushed. Default value is 2 GB The allowed range is up to 9223372036854775807.

`rocksdb_merge_buf_size`¶

Option	Description
Command-line	–rocksdb-merge-buf-size
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	67108864

Specifies the size (in bytes) of the merge-sort buffers used to accumulate data during secondary key creation. New entries are written directly to the lowest level in the database, instead of updating indexes through the memtable and L0. These values are sorted using merge-sort, with buffers set to 64 MB by default (67108864). Allowed range is from 100 to 18446744073709551615.

`rocksdb_merge_combine_read_size`¶

Option	Description
Command-line	–rocksdb-merge-combine-read-size
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	1073741824

Specifies the size (in bytes) of the merge-combine buffer used for the merge-sort algorithm as described in rocksdb_merge_buf_size. Default size is 1 GB (1073741824). Allowed range is from 100 to 18446744073709551615.

`rocksdb_merge_tmp_file_removal_delay_ms`¶

Option	Description
Command-line	–rocksdb_merge_tmp_file_removal_delay_ms
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	0

Fast secondary index creation creates merge files when needed. After finishing secondary index creation, merge files are removed. By default, the file removal is done without any sleep, so removing GBs of merge files within <1s may happen, which will cause trim stalls on Flash. This variable can be used to rate limit the delay in milliseconds.

`rocksdb_new_table_reader_for_compaction_inputs`¶

Option	Description
Command-line	–rocksdb-new-table-reader-for-compaction-inputs
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether MyRocks should create a new file descriptor and table reader for each compaction input. Disabled by default. Enabling this may increase memory consumption, but will also allow pre-fetch options to be specified for compaction input files without impacting table readers used for user queries.

`rocksdb_no_block_cache`¶

Option	Description
Command-line	–rocksdb-no-block-cache
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to disable the block cache for column families. Variable is disabled by default, meaning that using the block cache is allowed.

`rocksdb_no_create_column_family`¶

Option	Description
Command-line	–rocksdb-no-create-column-family
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Controls the processing of the column family name given in the COMMENT clause in the CREATE TABLE or ALTER TABLE statement in case the column family name does not refer to an existing column family.

If rocksdb_no_create_column_family is set to NO, a new column family will be created and the new index will be placed into it.

If rocksdb_no_create_column_family is set to YES, no new column family will be created and the index will be placed into the default column family. A warning is issued in this case informing that the specified column family does not exist and cannot be created.

`rocksdb_override_cf_options`¶

Option	Description
Command-line	–rocksdb-override-cf-options
Dynamic	No
Scope	Global
Data type	String
Default

Specifies option overrides for each column family. Empty by default.

`rocksdb_paranoid_checks`¶

Option	Description
Command-line	–rocksdb-paranoid-checks
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether MyRocks should re-read the data file as soon as it is created to verify correctness. Enabled by default.

`rocksdb_partial_index_ignore_killed`¶

Option	Description
Command-line	–rocksdb-partial-index-ignore-killed
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

This variable has been implemented in Percona Server for MySQL 8.0.36-28.

If this variable is set to ON, the partial index materialization ignores the killed flag and continues materialization until completion. If queries are killed during materialization due to timeout, the work done so far is wasted, and the killed query will likely be retried later, hitting the same issue.

The dafault value is ON which means this variable is enabled.

`rocksdb_partial_index_sort_max_mem`¶

Option	Description
Command-line	–rocksdb-partial-index-sort-max-mem
Dynamic	Yes
Scope	Local
Data type	Unsigned Integer
Default	0

The variable was implemented in Percona Server for MySQL 8.0.27-18. Maximum memory to use when sorting an unmaterialized group for partial indexes. The 0(zero) value is defined as no limit.

`rocksdb_pause_background_work`¶

Option	Description
Command-line	–rocksdb-pause-background-work
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether MyRocks should pause all background operations. Disabled by default. There is no practical reason for a user to ever use this variable because it is intended as a test synchronization tool for the MyRocks MTR test suites.

Warning

If someone were to set a rocksdb_force_flush_memtable_now to 1 while rocksdb_pause_background_work is set to 1, the client that issued the rocksdb_force_flush_memtable_now=1 will be blocked indefinitely until rocksdb_pause_background_work is set to 0.

`rocksdb_partial_index_blind_delete`¶

Option	Description
Command-line	–rocksdb_partial_index_blind_delete
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

The variable was implemented in Percona Server for MySQL 8.0.33-25.

If enabled, the server does not read from the partial index to check if the key exists before deleting the partial index and the delete marker is unconditionally written.

If the variable is disabled (OFF), the server always reads from partial index to check if key exists before deleting the partial index.

This variable is enabled (ON) by default.

`rocksdb_perf_context_level`¶

Option	Description
Command-line	–rocksdb-perf-context-level
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	0

Specifies the level of information to capture with the Perf Context plugins. The default value is 0. The allowed range is up to 5.

Value	Description
1	Disable perf stats
2	Enable only count stats
3	Enable count stats and time stats except for mutexes
4	Enable count stats and time stats, except for wall time or CPU time for mutexes
5	Enable all count stats and time stats

`rocksdb_persistent_cache_path`¶

Option	Description
Command-line	–rocksdb-persistent-cache-path
Dynamic	No
Scope	Global
Data type	String
Default

Specifies the path to the persistent cache. Set this together with rocksdb_persistent_cache_size_mb.

`rocksdb_persistent_cache_size_mb`¶

Option	Description
Command-line	–rocksdb-persistent-cache-size-mb
Dynamic	No
Scope	Global
Data type	Numeric
Default	0

Specifies the size of the persisten cache in megabytes. Default is 0 (persistent cache disabled). Allowed range is up to 18446744073709551615. Set this together with rocksdb_persistent_cache_path.

`rocksdb_pin_l0_filter_and_index_blocks_in_cache`¶

Option	Description
Command-line	–rocksdb-pin-l0-filter-and-index-blocks-in-cache
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether MyRocks pins the filter and index blocks in the cache if rocksdb_cache_index_and_filter_blocks is enabled. Enabled by default.

`rocksdb_print_snapshot_conflict_queries`¶

Option	Description
Command-line	–rocksdb-print-snapshot-conflict-queries
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether queries that generate snapshot conflicts should be logged to the error log. Disabled by default.

`rocksdb_protection_bytes_per_key`¶

Option	Description
Command-line	–rocksdb_protection_bytes_per_key
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	0

The variable was implemented in Percona Server for MySQL 8.0.33-25.

This variable is used to configure WriteOptions::protection_bytes_per_key. The default value is 0 (disabled). When this variable is set to 1, 2, 4, or 8, it uses that number of bytes per key value to protect entries in the WriteBatch.

The minimum value is 0.

The maximum value is ULONG_MAX (0xFFFFFFFF).

`rocksdb_rate_limiter_bytes_per_sec`¶

Option	Description
Command-line	–rocksdb-rate-limiter-bytes-per-sec
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

Specifies the maximum rate at which MyRocks can write to media via memtable flushes and compaction. Default value is 0 (write rate is not limited). Allowed range is up to 9223372036854775807.

`rocksdb_read_free_rpl`¶

Option	Description
Command-line	–rocksdb-read-free-rpl
Dynamic	Yes
Scope	Global
Data type	Enum
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.20-11. Uses read-free replication, which allows no row lookup during replication, on the replica.

The options are the following:

OFF - Disables the variable
PK_SK - Enables the variable on all tables with a primary key
PK_ONLY - Enables the variable on tables where the only key is the primary key

`rocksdb_read_free_rpl_tables`¶

Option	Description
Command-line	–rocksdb-read-free-rpl-tables
Dynamic	Yes
Scope	Global, Session
Data type	String
Default

The variable was disabled in Percona Server for MySQL 8.0.20-11. We recommend that you use rocksdb_read_free_rpl instead of this variable.

This variable lists tables (as a regular expression) that should use read-free replication on the replica (that is, replication without row lookups). Empty by default.

`rocksdb_records_in_range`¶

Option	Description
Command-line	–rocksdb-records-in-range
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	0

Specifies the value to override the result of records_in_range(). Default value is 0. Allowed range is up to 2147483647.

`rocksdb_reset_stats`¶

Option	Description
Command-line	–rocksdb-reset-stats
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Resets MyRocks internal statistics dynamically (without restarting the server).

`rocksdb_rollback_on_timeout`¶

Option	Description
Command-line	–rocksdb-rollback-on-timeout
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.20-11. By default, only the last statement on a transaction is rolled back. If --rocksdb-rollback-on-timeout=ON, a transaction timeout causes a rollback of the entire transaction.

`rocksdb_rpl_skip_tx_api`¶

Option	Description
Command-line	–rocksdb-rpl-skip-tx-api
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether write batches should be used for replication thread instead of the transaction API. Disabled by default.

There are two conditions which are necessary to use it: row replication format and replica operating in super read only mode.

`rocksdb_seconds_between_stat_computes`¶

Option	Description
Command-line	–rocksdb-seconds-between-stat-computes
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	3600

Specifies the number of seconds to wait between recomputation of table statistics for the optimizer. During that time, only changed indexes are updated. Default value is 3600. Allowed is from 0 to 4294967295.

`rocksdb_signal_drop_index_thread`¶

Option	Description
Command-line	–rocksdb-signal-drop-index-thread
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Signals the MyRocks drop index thread to wake up.

`rocksdb_sim_cache_size`¶

Option	Description
Command-line	–rocksdb-sim-cache-size
Dynamic	No
Scope	Global
Data type	Numeric
Default	0

Enables the simulated cache, which allows us to figure out the hit/miss rate with a specific cache size without changing the real block cache.

`rocksdb_skip_bloom_filter_on_read`¶

Option	Description
Command-line	–rocksdb-skip-bloom-filter-on_read
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Specifies whether bloom filters should be skipped on reads. Disabled by default (bloom filters are not skipped).

`rocksdb_skip_fill_cache`¶

Option	Description
Command-line	–rocksdb-skip-fill-cache
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Specifies whether to skip caching data on read requests. Disabled by default (caching is not skipped).

`rocksdb_skip_locks_if_skip_unique_check`¶

Option	Description
Command-line	rocksdb_skip_locks_if_skip_unique_check
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Skip row locking when unique checks are disabled.

`rocksdb_sst_mgr_rate_bytes_per_sec`¶

Option	Description
Command-line	–rocksdb-sst-mgr-rate-bytes-per-sec
Dynamic	Yes
Scope	Global, Session
Data type	Numeric
Default	0

Specifies the maximum rate for writing to data files. Default value is 0. This option is not effective on HDD. Allowed range is from 0 to 18446744073709551615.

`rocksdb_stats_dump_period_sec`¶

Option	Description
Command-line	–rocksdb-stats-dump-period-sec
Dynamic	No
Scope	Global
Data type	Numeric
Default	600

Specifies the period in seconds for performing a dump of the MyRocks statistics to the info log. Default value is 600. Allowed range is up to 2147483647.

`rocksdb_stats_level`¶

Option	Description
Command-line	–rocksdb-stats-level
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

The variable was implemented in Percona Server for MySQL 8.0.20-11. Controls the RocksDB statistics level. The default value is “0” (kExceptHistogramOrTimers), which is the fastest level. The maximum value is “4”.

`rocksdb_stats_recalc_rate`¶

Option	Description
Command-line	–rocksdb-stats-recalc-rate
Dynamic	No
Scope	Global
Data type	Numeric
Default	0

The variable was implemented in Percona Server for MySQL 8.0.20-11. Specifies the number of indexes to recalculate per second. Recalculating index statistics periodically ensures it to match the actual sum from SST files. Default value is 0. Allowed range is up to 4294967295.

`rocksdb_store_row_debug_checksums`¶

Option	Description
Command-line	–rocksdb-store-row-debug-checksums
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to include checksums when writing index or table records. Disabled by default.

`rocksdb_strict_collation_check`¶

Option	Description
Command-line	–rocksdb-strict-collation-check
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	ON

This variable is considered deprecated in version 8.0.23-14.

Specifies whether to check and verify that table indexes have proper collation settings. Enabled by default.

`rocksdb_strict_collation_exceptions`¶

Option	Description
Command-line	–rocksdb-strict-collation-exceptions
Dynamic	Yes
Scope	Global
Data type	String
Default

This variable is considered deprecated in version 8.0.23-14.

Lists tables (as a regular expression) that should be excluded from verifying case-sensitive collation enforced by rocksdb_strict_collation_check. Empty by default.

`rocksdb_table_cache_numshardbits`¶

Option	Description
Command-line	–rocksdb-table-cache-numshardbits
Dynamic	No
Scope	Global
Data type	Numeric
Default	6

Specifies the number if table caches. The default value is 6. The allowed range is from 0 to 19.

`rocksdb_table_stats_background_thread_nice_value`¶

Option	Description
Command-line	–rocksdb-table-stats-background-thread-nice-value
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	19

The variable was implemented in Percona Server for MySQL 8.0.20-11.

The nice value for index stats. The minimum = -20 (THREAD_PRIO_MIN) The maximum = 19 (THREAD_PRIO_MAX)

`rocksdb_table_stats_max_num_rows_scanned`¶

Option	Description
Command-line	–rocksdb-table-stats-max-num-rows-scanned
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

The variable was implemented in Percona Server for MySQL 8.0.20-11.

The maximum number of rows to scan in a table scan based on a cardinality calculation. The minimum is 0 (every modification triggers a stats recalculation). The maximum is 18,446,744,073,709,551,615.

`rocksdb_table_stats_recalc_threshold_count`¶

Option	Description
Command-line	–rocksdb-table-stats-recalc-threshold-count
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	100

The variable was implemented in Percona Server for MySQL 8.0.20-11.

The number of modified rows to trigger a stats recalculation. This is a dependent variable for stats recalculation. The minimum is 0. The maximum is 18,446,744,073,709,551,615.

`rocksdb_table_stats_recalc_threshold_pct`¶

Option	Description
Command-line	–rocksdb-table-stats-recalc-threshold-pct
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	10

The variable was implemented in Percona Server for MySQL 8.0.20-11.

The percentage of the number of modified rows over the total number of rows to trigger stats recalculations. This is a dependent variable for stats recalculation. The minimum value is 0 The maximum value is 100 (RDB_TBL_STATS_RECALC_THRESHOLD_PCT_MAX).

`rocksdb_table_stats_sampling_pct`¶

Option	Description
Command-line	–rocksdb-table-stats-sampling-pct
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	10

Specifies the percentage of entries to sample when collecting statistics about table properties. Default value is 10. Allowed range is from 0 to 100.

`rocksdb_table_stats_use_table_scan`¶

Option	Description
Command-line	–rocksdb-table-stats-use-table-scan
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.20-11. Enables table-scan-based index calculations. The default value is OFF.

`rocksdb_tmpdir`¶

Option	Description
Command-line	–rocksdb-tmpdir
Dynamic	Yes
Scope	Global, Session
Data type	String
Default

Specifies the path to the directory for temporary files during DDL operations.

`rocksdb_trace_block_cache_access`¶

Option	Description
Command-line	–rocksdb-trace-block-cache-access
Dynamic	Yes
Scope	Global
Data type	String
Default	""

The variable was implemented in Percona Server for MySQL 8.0.20-11. Defines the block cache trace option string. The format is sampling frequency: max_trace_file_size:trace_file_name. The sampling frequency value and max_trace_file_size value are positive integers. The block accesses are saved to the rocksdb_datadir/block_cache_traces/trace_file_name. The default value is an empty string.

`rocksdb_trace_queries`¶

Option	Description
Command-line	–rocksdb-trace-queries
Dynamic	Yes
Scope	Global
Data type	String
Default	""

This variable is a trace option string. The format is sampling_frequency:max_trace_file_size:trace_file_name. The sampling_frequency and max_trace_file_size are positive integers. The queries are saved to the rocksdb_datadir/queries_traces/trace_file_name.

`rocksdb_trace_sst_api`¶

Option	Description
Command-line	–rocksdb-trace-sst-api
Dynamic	Yes
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to generate trace output in the log for each call to SstFileWriter. Disabled by default.

`rocksdb_track_and_verify_wals_in_manifest`¶

Option	Description
Command-line	–rocksdb-track-and-verify-wals-in-manifest
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

DBOptions::track_and_verify_wals_in_manifest for RocksDB.

`rocksdb_two_write_queues`¶

Option	Description
Command-line	–rocksdb-track-and-verify-wals-in-manifest
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

When enabled this variable allows/encourages threads that are using two-phase commit to prepare in parallel.

`rocksdb_unsafe_for_binlog`¶

Option	Description
Command-line	–rocksdb-unsafe-for-binlog
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Specifies whether to allow statement-based binary logging which may break consistency. Disabled by default.

`rocksdb_update_cf_options`¶

Option	Description
Command-line	–rocksdb-update-cf-options
Dynamic	No
Scope	Global
Data type	String
Default

Specifies option updates for each column family. Empty by default.

`rocksdb_use_adaptive_mutex`¶

Option	Description
Command-line	–rocksdb-use-adaptive-mutex
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to use adaptive mutex which spins in user space before resorting to the kernel. Disabled by default.

`rocksdb_use_default_sk_cf`¶

Option	Description
Command-line	–rocksdb-use-default-sk-cf
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Use default_sk column family for secondary keys.

`rocksdb_use_direct_io_for_flush_and_compaction`¶

Option	Description
Command-line	–rocksdb-use-direct-io-for-flush-and-compaction
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to write to data files directly, without caches or buffers. Disabled by default.

`rocksdb_use_direct_reads`¶

Option	Description
Command-line	–rocksdb-use-direct-reads
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether to read data files directly, without caches or buffers. Disabled by default. If you enable this, make sure that rocksdb_allow_mmap_reads is disabled.

`rocksdb_use_fsync`¶

Option	Description
Command-line	–rocksdb-use-fsync
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

Specifies whether MyRocks should use fsync instead of fdatasync when requesting a sync of a data file. Disabled by default.

`rocksdb_use_hyper_clock_cache`¶

Option	Description
Command-line	–rocksdb_use_hyper_clock_cache
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.33-25.

If enabled, this variable uses HyperClockCache instead of default LRUCache for RocksDB.

This variable is disabled (OFF) by default.

`rocksdb_use_write_buffer_manager`¶

Option	Description
Command-line	–rocksdb_use_write_buffer_manager
Dynamic	No
Scope	Global
Data type	Boolean
Default	OFF

The variable was implemented in Percona Server for MySQL 8.0.33-25.

This variable is tech preview and may be removed in the future releases.

Allows to turn on the write buffer manager (WriteBufferManager) from cnf files. This variable is related to rocksdb_charge_memory.

`rocksdb_validate_tables`¶

Option	Description
Command-line	–rocksdb-validate-tables
Dynamic	No
Scope	Global
Data type	Numeric
Default	1

The variable was implemented in Percona Server for MySQL 8.0.20-11. Specifies whether to verify that MySQL data dictionary is equal to the MyRocks data dictionary.

0: do not verify.
1: verify and fail on error (default).
2: verify and continue with error.

`rocksdb_verify_row_debug_checksums`¶

Option	Description
Command-line	–rocksdb-verify-row-debug-checksums
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Specifies whether to verify checksums when reading index or table records. Disabled by default.

`rocksdb_wal_bytes_per_sync`¶

Option	Description
Command-line	–rocksdb-wal-bytes-per-sync
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

Specifies how often should the OS sync WAL (write-ahead log) files to disk as they are being written, asynchronously, in the background. This operation can be used to smooth out write I/O over time. Default value is 0, meaning that files are never synced. Allowed range is up to 18446744073709551615.

`rocksdb_wal_dir`¶

Option	Description
Command-line	–rocksdb-wal-dir
Dynamic	No
Scope	Global
Data type	String
Default

Specifies the path to the directory where MyRocks stores WAL files.

`rocksdb_wal_recovery_mode`¶

Option	Description
Command-line	–rocksdb-wal-recovery-mode
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	2

Note

In version Percona Server for MySQL 8.0.20-11 and later, the default is changed from 1 to 2.

Specifies the level of tolerance when recovering write-ahead logs (WAL) files after a system crash.

The following are the options:

0: if the last WAL entry is corrupted, truncate the entry and either start the server normally or refuse to start.
1: if a WAL entry is corrupted, the server fails to start and does not recover from the crash.
2 (default): if a corrupted WAL entry is detected, truncate all entries after the detected corrupted entry. You can select this setting for replication replicas.
3: If a corrupted WAL entry is detected, skip only the corrupted entry and continue the apply WAL entries. This option can be dangerous.

`rocksdb_wal_size_limit_mb`¶

Option	Description
Command-line	–rocksdb-wal-size-limit-mb
Dynamic	No
Scope	Global
Data type	Numeric
Default	0

Specifies the maximum size of all WAL files in megabytes before attempting to flush memtables and delete the oldest files. Default value is 0 (never rotated). Allowed range is up to 9223372036854775807.

`rocksdb_wal_ttl_seconds`¶

Option	Description
Command-line	–rocksdb-wal-ttl-seconds
Dynamic	No
Scope	Global
Data type	Numeric
Default	0

Specifies the timeout in seconds before deleting archived WAL files. Default is 0 (archived WAL files are never deleted). Allowed range is up to 9223372036854775807.

`rocksdb_whole_key_filtering`¶

Option	Description
Command-line	–rocksdb-whole-key-filtering
Dynamic	No
Scope	Global
Data type	Boolean
Default	ON

Specifies whether the bloomfilter should use the whole key for filtering instead of just the prefix. Enabled by default. Make sure that lookups use the whole key for matching.

`rocksdb_write_batch_flush_threshold`¶

Option	Description
Command-line	–rocksdb-write-batch-flush-threshold
Dynamic	Yes
Scope	Local
Data type	Integer
Default	0

This variable specifies the maximum size of the write batch in bytes before flushing. Only valid if rockdb_write_policy is WRITE_UNPREPARED. There is no limit if the variable is set to the default setting.

`rocksdb_write_batch_max_bytes`¶

Option	Description
Command-line	–rocksdb-write-batch-max-bytes
Dynamic	Yes
Scope	Global
Data type	Numeric
Default	0

Specifies the maximum size of a RocksDB write batch in bytes. 0 means no limit. In case user exceeds the limit following error will be shown: ERROR HY000: Status error 10 received from RocksDB: Operation aborted: Memory limit reached.

`rocksdb_write_disable_wal`¶

Option	Description
Command-line	–rocksdb-write-disable-wal
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Lets you temporarily disable writes to WAL files, which can be useful for bulk loading.

`rocksdb_write_ignore_missing_column_families`¶

Option	Description
Command-line	–rocksdb-write-ignore-missing-column-families
Dynamic	Yes
Scope	Global, Session
Data type	Boolean
Default	OFF

Specifies whether to ignore writes to column families that do not exist. Disabled by default (writes to non-existent column families are not ignored).

`rocksdb_write_policy`¶

Option	Description
Command-line	–rocksdb-write-policy
Dynamic	No
Scope	Global
Data type	String
Default	write_committed

Specifies when two-phase commit data are written into the database. Allowed values are write_committed, write_prepared, and write_unprepared.

Value	Description
`write_committed`	Data written at commit time
`write_prepared`	Data written after the prepare phase of a two-phase transaction
`write_unprepared`	Data written before the prepare phase of a two-phase transaction

MyRocks server variables¶

rocksdb_access_hint_on_compaction_start¶

rocksdb_advise_random_on_open¶

rocksdb_allow_concurrent_memtable_write¶

rocksdb_allow_to_start_after_corruption¶

rocksdb_allow_mmap_reads¶

rocksdb_allow_mmap_writes¶

rocksdb_allow_unsafe_alter¶

rocksdb_alter_column_default_inplace¶

rocksdb_alter_table_comment_inplace¶

rocksdb_base_background_compactions¶

rocksdb_blind_delete_primary_key¶

rocksdb_block_cache_numshardbits¶

rocksdb_block_cache_size¶

rocksdb_bulk_load_fail_if_not_bottommost_level¶

rocksdb_block_restart_interval¶

rocksdb_block_size¶

rocksdb_block_size_deviation¶

rocksdb_bulk_load_allow_sk¶

rocksdb_bulk_load_allow_unsorted¶

rocksdb_bulk_load¶

rocksdb_bulk_load_partial_index¶

rocksdb_bulk_load_use_sst_partitioner¶

rocksdb_bulk_load_size¶

rocksdb_bytes_per_sync¶

rocksdb_cache_dump¶

rocksdb_cache_high_pri_pool_ratio¶

rocksdb_cache_index_and_filter_blocks¶

rocksdb_cache_index_and_filter_with_high_priority¶

rocksdb_cancel_manual_compactions¶

rocksdb_charge_memory¶

rocksdb_check_iterate_bounds¶

rocksdb_checksums_pct¶

rocksdb_collect_sst_properties¶

rocksdb_column_default_value_as_expression¶

rocksdb_commit_in_the_middle¶

rocksdb_commit_time_batch_for_recovery¶

rocksdb_compact_cf¶

rocksdb_compact_lzero_now¶

rocksdb_compaction_readahead_size¶

rocksdb_compaction_sequential_deletes¶

rocksdb_compaction_sequential_deletes_count_sd¶

rocksdb_compaction_sequential_deletes_file_size¶

rocksdb_compaction_sequential_deletes_window¶

rocksdb_concurrent_prepare¶

rocksdb_corrupt_data_action¶

rocksdb_converter_record_cached_length¶

rocksdb_create_checkpoint¶

rocksdb_create_if_missing¶

rocksdb_create_missing_column_families¶

rocksdb_create_temporary_checkpoint¶

rocksdb_datadir¶

rocksdb_db_write_buffer_size¶

rocksdb_deadlock_detect¶

rocksdb_deadlock_detect_depth¶

rocksdb_debug_cardinality_multiplier¶

rocksdb_debug_manual_compaction_delay¶

rocksdb_debug_optimizer_no_zero_cardinality¶

rocksdb_debug_ttl_ignore_pk¶

rocksdb_debug_ttl_read_filter_ts¶

rocksdb_debug_ttl_rec_ts¶

rocksdb_debug_ttl_snapshot_ts¶

rocksdb_default_cf_options¶

rocksdb_delayed_write_rate¶

rocksdb_delete_cf¶

rocksdb_delete_obsolete_files_period_micros¶

rocksdb_disable_file_deletions¶

rocksdb_disable_instant_ddl¶

rocksdb_enable_bulk_load_api¶

rocksdb_enable_delete_range_for_drop_index¶

rocksdb_enable_insert_with_update_caching¶

rocksdb_enable_iterate_bounds¶

rocksdb_enable_pipelined_write¶

rocksdb_enable_remove_orphaned_dropped_cfs¶

rocksdb_enable_ttl¶

rocksdb_enable_ttl_read_filtering¶

rocksdb_enable_thread_tracking¶

rocksdb_enable_write_thread_adaptive_yield¶

rocksdb_error_if_exists¶

rocksdb_error_on_suboptimal_collation¶

`rocksdb_access_hint_on_compaction_start`¶

`rocksdb_advise_random_on_open`¶

`rocksdb_allow_concurrent_memtable_write`¶

`rocksdb_allow_to_start_after_corruption`¶

`rocksdb_allow_mmap_reads`¶

`rocksdb_allow_mmap_writes`¶

`rocksdb_allow_unsafe_alter`¶

`rocksdb_alter_column_default_inplace`¶

`rocksdb_alter_table_comment_inplace`¶

`rocksdb_base_background_compactions`¶

`rocksdb_blind_delete_primary_key`¶

`rocksdb_block_cache_numshardbits`¶

`rocksdb_block_cache_size`¶

`rocksdb_bulk_load_fail_if_not_bottommost_level`¶

`rocksdb_block_restart_interval`¶

`rocksdb_block_size`¶

`rocksdb_block_size_deviation`¶

`rocksdb_bulk_load_allow_sk`¶

`rocksdb_bulk_load_allow_unsorted`¶

`rocksdb_bulk_load`¶

`rocksdb_bulk_load_partial_index`¶

`rocksdb_bulk_load_use_sst_partitioner`¶

`rocksdb_bulk_load_size`¶

`rocksdb_bytes_per_sync`¶

`rocksdb_cache_dump`¶

`rocksdb_cache_high_pri_pool_ratio`¶

`rocksdb_cache_index_and_filter_blocks`¶

`rocksdb_cache_index_and_filter_with_high_priority`¶

`rocksdb_cancel_manual_compactions`¶

`rocksdb_charge_memory`¶

`rocksdb_check_iterate_bounds`¶

`rocksdb_checksums_pct`¶

`rocksdb_collect_sst_properties`¶

`rocksdb_column_default_value_as_expression`¶

`rocksdb_commit_in_the_middle`¶

`rocksdb_commit_time_batch_for_recovery`¶

`rocksdb_compact_cf`¶

`rocksdb_compact_lzero_now`¶

`rocksdb_compaction_readahead_size`¶

`rocksdb_compaction_sequential_deletes`¶

`rocksdb_compaction_sequential_deletes_count_sd`¶

`rocksdb_compaction_sequential_deletes_file_size`¶

`rocksdb_compaction_sequential_deletes_window`¶

`rocksdb_concurrent_prepare`¶

`rocksdb_corrupt_data_action`¶

`rocksdb_converter_record_cached_length`¶

`rocksdb_create_checkpoint`¶

`rocksdb_create_if_missing`¶

`rocksdb_create_missing_column_families`¶

`rocksdb_create_temporary_checkpoint`¶

`rocksdb_datadir`¶

`rocksdb_db_write_buffer_size`¶

`rocksdb_deadlock_detect`¶

`rocksdb_deadlock_detect_depth`¶

`rocksdb_debug_cardinality_multiplier`¶

`rocksdb_debug_manual_compaction_delay`¶

`rocksdb_debug_optimizer_no_zero_cardinality`¶

`rocksdb_debug_ttl_ignore_pk`¶

`rocksdb_debug_ttl_read_filter_ts`¶

`rocksdb_debug_ttl_rec_ts`¶

`rocksdb_debug_ttl_snapshot_ts`¶

`rocksdb_default_cf_options`¶

`rocksdb_delayed_write_rate`¶

`rocksdb_delete_cf`¶

`rocksdb_delete_obsolete_files_period_micros`¶

`rocksdb_disable_file_deletions`¶

`rocksdb_disable_instant_ddl`¶

`rocksdb_enable_bulk_load_api`¶

`rocksdb_enable_delete_range_for_drop_index`¶

`rocksdb_enable_insert_with_update_caching`¶

`rocksdb_enable_iterate_bounds`¶

`rocksdb_enable_pipelined_write`¶

`rocksdb_enable_remove_orphaned_dropped_cfs`¶

`rocksdb_enable_ttl`¶

`rocksdb_enable_ttl_read_filtering`¶

`rocksdb_enable_thread_tracking`¶

`rocksdb_enable_write_thread_adaptive_yield`¶

`rocksdb_error_if_exists`¶

`rocksdb_error_on_suboptimal_collation`¶

`rocksdb_file_checksums`¶