The table_io_waits_summary_by_table
table aggregates all table I/O wait events, as generated by the wait/io/table/sql/handler
instrument. The grouping is by table.
The table_io_waits_summary_by_table
table has these grouping columns to indicate how the table aggregates events: OBJECT_TYPE
, OBJECT_SCHEMA
, and OBJECT_NAME
. These columns have the same meaning as in the events_waits_current
table. They identify the table to which the row applies.
table_io_waits_summary_by_table
has the following summary columns containing aggregated values. As indicated in the column descriptions, some columns are more general and have values that are the same as the sum of the values of more fine-grained columns. For example, columns that aggregate all writes hold the sum of the corresponding columns that aggregate inserts, updates, and deletes. In this way, aggregations at higher levels are available directly without the need for user-defined views that sum lower-level columns.
COUNT_STAR
, SUM_TIMER_WAIT
, MIN_TIMER_WAIT
, AVG_TIMER_WAIT
, MAX_TIMER_WAIT
These columns aggregate all I/O operations. They are the same as the sum of the corresponding
and xxx
_READ
columns.xxx
_WRITE
COUNT_READ
, SUM_TIMER_READ
, MIN_TIMER_READ
, AVG_TIMER_READ
, MAX_TIMER_READ
These columns aggregate all read operations. They are the same as the sum of the corresponding
columns.xxx
_FETCH
COUNT_WRITE
, SUM_TIMER_WRITE
, MIN_TIMER_WRITE
, AVG_TIMER_WRITE
, MAX_TIMER_WRITE
These columns aggregate all write operations. They are the same as the sum of the corresponding
, xxx
_INSERT
, and xxx
_UPDATE
columns.xxx
_DELETE
COUNT_FETCH
, SUM_TIMER_FETCH
, MIN_TIMER_FETCH
, AVG_TIMER_FETCH
, MAX_TIMER_FETCH
These columns aggregate all fetch operations.
COUNT_INSERT
, SUM_TIMER_INSERT
, MIN_TIMER_INSERT
, AVG_TIMER_INSERT
, MAX_TIMER_INSERT
These columns aggregate all insert operations.
COUNT_UPDATE
, SUM_TIMER_UPDATE
, MIN_TIMER_UPDATE
, AVG_TIMER_UPDATE
, MAX_TIMER_UPDATE
These columns aggregate all update operations.
COUNT_DELETE
, SUM_TIMER_DELETE
, MIN_TIMER_DELETE
, AVG_TIMER_DELETE
, MAX_TIMER_DELETE
These columns aggregate all delete operations.
The table_io_waits_summary_by_table
table has these indexes:
Unique index on (OBJECT_TYPE
, OBJECT_SCHEMA
, OBJECT_NAME
)
TRUNCATE TABLE
is permitted for table I/O summary tables. It resets the summary columns to zero rather than removing rows. Truncating this table also truncates the table_io_waits_summary_by_index_usage
table.