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
SETstatement. -
If you want to test things out, you can set some of the variables when starting
mysqldusing 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.
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 |
Enable 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_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
DELETEstatement -
The table has only a primary key with no secondary keys
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_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_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_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_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_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 | 0 |
Specifies the threshold to trigger compaction on a file
if it has more than this number of sequential delete markers.
Default value is 0 meaning that compaction is not triggered
regardless of the number of delete markers.
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 | OFF |
Specifies whether to count single deletes as delete markers recognized by rocksdb_compaction_sequential_deletes. Disabled by default.
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 | 0 |
Specifies the size of the window for counting delete markers
by rocksdb_compaction_sequential_deletes.
Default value is 0.
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_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_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_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 | TRUE |
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 | TRUE |
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 TRUE.
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_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 |
Forces MyRocks to immediately flush all memtables out to data files.
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 | TRUE |
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 TRUE.
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.
This variable was re-implemented in :ref: 8.0.20-11.
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_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_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_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_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 | FALSE |
The variable was implemented in Percona Server for MySQL 8.0.20-11. Enables table-scan-based index calculations.
The default value is FALSE.
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_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 |
