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

Specifies whether to keep expired TTL records during compaction. Enabled by default. If disabled, expired TTL records will be dropped 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 will allow these records to be seen, but as a result rows may disappear in the middle of transactions as they are dropped 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

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Last update: 2024-03-04