The Ultimate Guide to High Availability with MariaDB

Performance Schema table_io_waits_summary_by_index_usage Table

The table_io_waits_summary_by_index_usage table records table I/O waits by index.

ColumnDescription
OBJECT_TYPETABLE in the case of all indexes.
OBJECT_SCHEMASchema name.
OBJECT_NAMETable name.
INDEX_NAMEIndex name, or PRIMARY for the primary index, NULL for no index (inserts are counted in this case).
COUNT_STARNumber of summarized events and the sum of the x_READ and x_WRITE columns.
SUM_TIMER_WAITTotal wait time of the summarized events that are timed.
MIN_TIMER_WAITMinimum wait time of the summarized events that are timed.
AVG_TIMER_WAITAverage wait time of the summarized events that are timed.
MAX_TIMER_WAITMaximum wait time of the summarized events that are timed.
COUNT_READNumber of all read operations, and the sum of the equivalent x_FETCH columns.
SUM_TIMER_READTotal wait time of all read operations that are timed.
MIN_TIMER_READMinimum wait time of all read operations that are timed.
AVG_TIMER_READAverage wait time of all read operations that are timed.
MAX_TIMER_READMaximum wait time of all read operations that are timed.
COUNT_WRITENumber of all write operations, and the sum of the equivalent x_INSERT, x_UPDATE and x_DELETE columns.
SUM_TIMER_WRITETotal wait time of all write operations that are timed.
MIN_TIMER_WRITEMinimum wait time of all write operations that are timed.
AVG_TIMER_WRITEAverage wait time of all write operations that are timed.
MAX_TIMER_WRITEMaximum wait time of all write operations that are timed.
COUNT_FETCHNumber of all fetch operations.
SUM_TIMER_FETCHTotal wait time of all fetch operations that are timed.
MIN_TIMER_FETCHMinimum wait time of all fetch operations that are timed.
AVG_TIMER_FETCHAverage wait time of all fetch operations that are timed.
MAX_TIMER_FETCHMaximum wait time of all fetch operations that are timed.
COUNT_INSERTNumber of all insert operations.
SUM_TIMER_INSERTTotal wait time of all insert operations that are timed.
MIN_TIMER_INSERTMinimum wait time of all insert operations that are timed.
AVG_TIMER_INSERTAverage wait time of all insert operations that are timed.
MAX_TIMER_INSERTMaximum wait time of all insert operations that are timed.
COUNT_UPDATENumber of all update operations.
SUM_TIMER_UPDATETotal wait time of all update operations that are timed.
MIN_TIMER_UPDATEMinimum wait time of all update operations that are timed.
AVG_TIMER_UPDATEAverage wait time of all update operations that are timed.
MAX_TIMER_UPDATEMaximum wait time of all update operations that are timed.
COUNT_DELETENumber of all delete operations.
SUM_TIMER_DELETETotal wait time of all delete operations that are timed.
MIN_TIMER_DELETEMinimum wait time of all delete operations that are timed.
AVG_TIMER_DELETEAverage wait time of all delete operations that are timed.
MAX_TIMER_DELETEMaximum wait time of all delete operations that are timed.

You can TRUNCATE the table, which will reset all counters to zero. The table is also truncated if the table_io_waits_summary_by_table table is truncated.

If a table's index structure is changed, index statistics recorded in this table may also be reset.

Comments

Comments loading...
Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.