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.
