MyRocks status variables¶
MyRocks status variables provide details about the inner workings of the storage engine and they can be useful in tuning the storage engine to a particular environment.
You can view these variables and their values by running:
mysql> SHOW STATUS LIKE 'rocksdb%';
The following global status variables are available:
rocksdb_rows_deleted¶
This variable shows the number of rows that were deleted from MyRocks tables.
rocksdb_rows_inserted¶
This variable shows the number of rows that were inserted into MyRocks tables.
rocksdb_rows_read¶
This variable shows the number of rows that were read from MyRocks tables.
rocksdb_rows_unfiltered_no_snapshot¶
This variable shows how many reads need TTL and have no snapshot timestamp.
rocksdb_rows_updated¶
This variable shows the number of rows that were updated in MyRocks tables.
rocksdb_rows_expired¶
This variable shows the number of expired rows in MyRocks tables.
rocksdb_system_rows_deleted¶
This variable shows the number of rows that were deleted from MyRocks system tables.
rocksdb_system_rows_inserted¶
This variable shows the number of rows that were inserted into MyRocks system tables.
rocksdb_system_rows_read¶
This variable shows the number of rows that were read from MyRocks system tables.
rocksdb_system_rows_updated¶
This variable shows the number of rows that were updated in MyRocks system tables.
rocksdb_memtable_total¶
This variable shows the memory usage, in bytes, of all memtables.
rocksdb_memtable_unflushed¶
This variable shows the memory usage, in bytes, of all unflushed memtables.
rocksdb_queries_point¶
This variable shows the number of single row queries.
rocksdb_queries_range¶
This variable shows the number of multi/range row queries.
rocksdb_covered_secondary_key_lookups¶
This variable shows the number of lookups via the secondary index that returned all fields requested directly from the secondary index.
rocksdb_additional_compactions_trigger¶
This variable shows the number of triggered additional compactions. MyRocks triggers an additional compaction if (number of deletions / number of entries) > (rocksdb_compaction_sequential_deletes / rocksdb_compaction_sequential_deletes_window) in the SST file.
rocksdb_block_cache_add¶
This variable shows the number of blocks added to block cache.
rocksdb_block_cache_add_failures¶
This variable shows the number of failures when adding blocks to block cache.
rocksdb_block_cache_bytes_read¶
This variable shows the number of bytes read from cache.
rocksdb_block_cache_bytes_write¶
This variable shows the number of bytes written into cache.
rocksdb_block_cache_data_add¶
This variable shows the number of data blocks added to block cache.
rocksdb_block_cache_data_bytes_insert¶
This variable shows the number of bytes of data blocks inserted into cache.
rocksdb_block_cache_data_hit¶
This variable shows the number of cache hits when accessing the data block from the block cache.
rocksdb_block_cache_data_miss¶
This variable shows the number of cache misses when accessing the data block from the block cache.
rocksdb_block_cache_filter_add¶
This variable shows the number of filter blocks added to block cache.
rocksdb_block_cache_filter_bytes_evict¶
This variable shows the number of bytes of bloom filter blocks removed from cache.
rocksdb_block_cache_filter_bytes_insert¶
This variable shows the number of bytes of bloom filter blocks inserted into cache.
rocksdb_block_cache_filter_hit¶
This variable shows the number of times cache hit when accessing filter block from block cache.
rocksdb_block_cache_filter_miss¶
This variable shows the number of times cache miss when accessing filter block from block cache.
rocksdb_block_cache_hit¶
This variable shows the total number of block cache hits.
rocksdb_block_cache_index_add¶
This variable shows the number of index blocks added to block cache.
rocksdb_block_cache_index_bytes_evict¶
This variable shows the number of bytes of index block erased from cache.
rocksdb_block_cache_index_bytes_insert¶
This variable shows the number of bytes of index blocks inserted into cache.
rocksdb_block_cache_index_hit¶
This variable shows the total number of block cache index hits.
rocksdb_block_cache_index_miss¶
This variable shows the number of times cache hit when accessing index block from block cache.
rocksdb_block_cache_miss¶
This variable shows the total number of block cache misses.
rocksdb_block_cache_compressed_hit¶
This variable shows the number of hits in the compressed block cache.
rocksdb_block_cache_compressed_miss¶
This variable shows the number of misses in the compressed block cache.
rocksdb_bloom_filter_prefix_checked¶
This variable shows the number of times bloom was checked before creating iterator on a file.
rocksdb_bloom_filter_prefix_useful¶
This variable shows the number of times the check was useful in avoiding iterator creation (and thus likely IOPs).
rocksdb_bloom_filter_useful¶
This variable shows the number of times bloom filter has avoided file reads.
rocksdb_bytes_read¶
This variable shows the total number of uncompressed bytes read. It could be either from memtables, cache, or table files.
rocksdb_bytes_written¶
This variable shows the total number of uncompressed bytes written.
rocksdb_compact_read_bytes¶
This variable shows the number of bytes read during compaction
rocksdb_compact_write_bytes¶
This variable shows the number of bytes written during compaction.
rocksdb_compaction_key_drop_new¶
This variable shows the number of key drops during compaction because it was overwritten with a newer value.
rocksdb_compaction_key_drop_obsolete¶
This variable shows the number of key drops during compaction because it was obsolete.
rocksdb_compaction_key_drop_user¶
This variable shows the number of key drops during compaction because user compaction function has dropped the key.
rocksdb_flush_write_bytes¶
This variable shows the number of bytes written during flush.
rocksdb_get_hit_l0¶
This variable shows the number of Get() queries served by L0.
rocksdb_get_hit_l1¶
This variable shows the number of Get() queries served by L1.
rocksdb_get_hit_l2_and_up¶
This variable shows the number of Get() queries served by L2 and up.
rocksdb_get_updates_since_calls¶
This variable shows the number of calls to GetUpdatesSince function.
Useful to keep track of transaction log iterator refreshes
rocksdb_iter_bytes_read¶
This variable shows the number of uncompressed bytes read from an iterator. It includes size of key and value.
rocksdb_memtable_hit¶
This variable shows the number of memtable hits.
rocksdb_memtable_miss¶
This variable shows the number of memtable misses.
rocksdb_no_file_closes¶
This variable shows the number of time file were closed.
rocksdb_no_file_errors¶
This variable shows number of errors trying to read in data from an sst file.
rocksdb_no_file_opens¶
This variable shows the number of time file were opened.
rocksdb_num_iterators¶
This variable shows the number of currently open iterators.
rocksdb_number_block_not_compressed¶
This variable shows the number of uncompressed blocks.
rocksdb_number_db_next¶
This variable shows the number of calls to next.
rocksdb_number_db_next_found¶
This variable shows the number of calls to next that returned data.
rocksdb_number_db_prev¶
This variable shows the number of calls to prev.
rocksdb_number_db_prev_found¶
This variable shows the number of calls to prev that returned data.
rocksdb_number_db_seek¶
This variable shows the number of calls to seek.
rocksdb_number_db_seek_found¶
This variable shows the number of calls to seek that returned data.
rocksdb_number_deletes_filtered¶
This variable shows the number of deleted records that were not required to be written to storage because key did not exist.
rocksdb_number_keys_read¶
This variable shows the number of keys read.
rocksdb_number_keys_updated¶
This variable shows the number of keys updated, if inplace update is enabled.
rocksdb_number_keys_written¶
This variable shows the number of keys written to the database.
rocksdb_number_merge_failures¶
This variable shows the number of failures performing merge operator actions in RocksDB.
rocksdb_number_multiget_bytes_read¶
This variable shows the number of bytes read during RocksDB
MultiGet() calls.
rocksdb_number_multiget_get¶
This variable shows the number MultiGet() requests to RocksDB.
rocksdb_number_multiget_keys_read¶
This variable shows the keys read via MultiGet().
rocksdb_number_reseeks_iteration¶
This variable shows the number of times reseek happened inside an iteration to skip over large number of keys with same userkey.
rocksdb_number_sst_entry_delete¶
This variable shows the total number of delete markers written by MyRocks.
rocksdb_number_sst_entry_merge¶
This variable shows the total number of merge keys written by MyRocks.
rocksdb_number_sst_entry_other¶
This variable shows the total number of non-delete, non-merge, non-put keys written by MyRocks.
rocksdb_number_sst_entry_put¶
This variable shows the total number of put keys written by MyRocks.
rocksdb_number_sst_entry_singledelete¶
This variable shows the total number of single delete keys written by MyRocks.
rocksdb_number_stat_computes¶
This variable isn’t used anymore and will be removed in future releases.
rocksdb_number_superversion_acquires¶
This variable shows the number of times the superversion structure has been acquired in RocksDB, this is used for tracking all of the files for the database.
rocksdb_number_superversion_cleanups¶
rocksdb_number_superversion_releases¶
rocksdb_rate_limit_delay_millis¶
This variable was removed in Percona Server for MySQL Percona Server 5.7.23-23.
rocksdb_row_lock_deadlocks¶
This variable shows the total number of deadlocks that have been detected since the instance was started.
rocksdb_row_lock_wait_timeouts¶
This variable shows the total number of row lock wait timeouts that have been detected since the instance was started.
rocksdb_snapshot_conflict_errors¶
This variable shows the number of snapshot conflict errors occurring during write transactions that forces the transaction to rollback.
rocksdb_stall_l0_file_count_limit_slowdowns¶
This variable shows the slowdowns in write due to L0 being close to full.
rocksdb_stall_locked_l0_file_count_limit_slowdowns¶
This variable shows the slowdowns in write due to L0 being close to full and compaction for L0 is already in progress.
rocksdb_stall_l0_file_count_limit_stops¶
This variable shows the stalls in write due to L0 being full.
rocksdb_stall_locked_l0_file_count_limit_stops¶
This variable shows the stalls in write due to L0 being full and compaction for L0 is already in progress.
rocksdb_stall_pending_compaction_limit_stops¶
This variable shows the stalls in write due to hitting limits set for max number of pending compaction bytes.
rocksdb_stall_pending_compaction_limit_slowdowns¶
This variable shows the slowdowns in write due to getting close to limits set for max number of pending compaction bytes.
rocksdb_stall_memtable_limit_stops¶
This variable shows the stalls in write due to hitting max number of
memTables allowed.
rocksdb_stall_memtable_limit_slowdowns¶
This variable shows the slowdowns in writes due to getting close to max number of memtables allowed.
rocksdb_stall_total_stops¶
This variable shows the total number of write stalls.
rocksdb_stall_total_slowdowns¶
This variable shows the total number of write slowdowns.
rocksdb_stall_micros¶
This variable shows how long (in microseconds) the writer had to wait for compaction or flush to finish.
rocksdb_wal_bytes¶
This variables shows the number of bytes written to WAL.
rocksdb_wal_group_syncs¶
This variable shows the number of group commit WAL file syncs that have occurred.
rocksdb_wal_synced¶
This variable shows the number of times WAL sync was done.
rocksdb_write_other¶
This variable shows the number of writes processed by another thread.
rocksdb_write_self¶
This variable shows the number of writes that were processed by a requesting thread.
rocksdb_write_timedout¶
This variable shows the number of writes ending up with timed-out.
rocksdb_write_wal¶
This variable shows the number of Write calls that request WAL.
Get expert help¶
If you need assistance, visit the community forum for comprehensive and free database knowledge, or contact our Percona Database Experts for professional support and services.