> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/system-tables/performance-schema/performance-schema-tables/performance-schema-table_lock_waits_summary_by_table-table.md). # Performance Schema table\_lock\_waits\_summary\_by\_table Table This table aggregates table lock wait events, allowing administrators to identify tables experiencing high contention due to locking. The `table_lock_waits_summary_by_table` table records table lock waits by table. | Column | Description | | ------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | OBJECT\_TYPE | Since this table records waits by table, always set to TABLE. | | OBJECT\_SCHEMA | Schema name. | | OBJECT\_NAME | Table name. | | COUNT\_STAR | Number of summarized events and the sum of the x\_READ and x\_WRITE columns. | | SUM\_TIMER\_WAIT | Total wait time of the summarized events that are timed. | | MIN\_TIMER\_WAIT | Minimum wait time of the summarized events that are timed. | | AVG\_TIMER\_WAIT | Average wait time of the summarized events that are timed. | | MAX\_TIMER\_WAIT | Maximum wait time of the summarized events that are timed. | | COUNT\_READ | Number of all read operations, and the sum of the equivalent x\_READ\_NORMAL, x\_READ\_WITH\_SHARED\_LOCKS, x\_READ\_HIGH\_PRIORITY and x\_READ\_NO\_INSERT columns. | | SUM\_TIMER\_READ | Total wait time of all read operations that are timed. | | MIN\_TIMER\_READ | Minimum wait time of all read operations that are timed. | | AVG\_TIMER\_READ | Average wait time of all read operations that are timed. | | MAX\_TIMER\_READ | Maximum wait time of all read operations that are timed. | | COUNT\_WRITE | Number of all write operations, and the sum of the equivalent x\_WRITE\_ALLOW\_WRITE, x\_WRITE\_CONCURRENT\_INSERT, x\_WRITE\_DELAYED, x\_WRITE\_LOW\_PRIORITY and x\_WRITE\_NORMAL columns. | | SUM\_TIMER\_WRITE | Total wait time of all write operations that are timed. | | MIN\_TIMER\_WRITE | Minimum wait time of all write operations that are timed. | | AVG\_TIMER\_WRITE | Average wait time of all write operations that are timed. | | MAX\_TIMER\_WRITE | Maximum wait time of all write operations that are timed. | | COUNT\_READ\_NORMAL | Number of all internal read normal locks. | | SUM\_TIMER\_READ\_NORMAL | Total wait time of all internal read normal locks that are timed. | | MIN\_TIMER\_READ\_NORMAL | Minimum wait time of all internal read normal locks that are timed. | | AVG\_TIMER\_READ\_NORMAL | Average wait time of all internal read normal locks that are timed. | | MAX\_TIMER\_READ\_NORMAL | Maximum wait time of all internal read normal locks that are timed. | | COUNT\_READ\_WITH\_SHARED\_LOCKS | Number of all internal read with shared locks. | | SUM\_TIMER\_READ\_WITH\_SHARED\_LOCKS | Total wait time of all internal read with shared locks that are timed. | | MIN\_TIMER\_READ\_WITH\_SHARED\_LOCKS | Minimum wait time of all internal read with shared locks that are timed. | | AVG\_TIMER\_READ\_WITH\_SHARED\_LOCKS | Average wait time of all internal read with shared locks that are timed. | | MAX\_TIMER\_READ\_WITH\_SHARED\_LOCKS | Maximum wait time of all internal read with shared locks that are timed. | | COUNT\_READ\_HIGH\_PRIORITY | Number of all internal read high priority locks. | | SUM\_TIMER\_READ\_HIGH\_PRIORITY | Total wait time of all internal read high priority locks that are timed. | | MIN\_TIMER\_READ\_HIGH\_PRIORITY | Minimum wait time of all internal read high priority locks that are timed. | | AVG\_TIMER\_READ\_HIGH\_PRIORITY | Average wait time of all internal read high priority locks that are timed. | | MAX\_TIMER\_READ\_HIGH\_PRIORITY | Maximum wait time of all internal read high priority locks that are timed. | | COUNT\_READ\_NO\_INSERT | Number of all internal read no insert locks. | | SUM\_TIMER\_READ\_NO\_INSERT | Total wait time of all internal read no insert locks that are timed. | | MIN\_TIMER\_READ\_NO\_INSERT | Minimum wait time of all internal read no insert locks that are timed. | | AVG\_TIMER\_READ\_NO\_INSERT | Average wait time of all internal read no insert locks that are timed. | | MAX\_TIMER\_READ\_NO\_INSERT | Maximum wait time of all internal read no insert locks that are timed. | | COUNT\_READ\_EXTERNAL | Number of all external read locks. | | SUM\_TIMER\_READ\_EXTERNAL | Total wait time of all external read locks that are timed. | | MIN\_TIMER\_READ\_EXTERNAL | Minimum wait time of all external read locks that are timed. | | AVG\_TIMER\_READ\_EXTERNAL | Average wait time of all external read locks that are timed. | | MAX\_TIMER\_READ\_EXTERNAL | Maximum wait time of all external read locks that are timed. | | COUNT\_WRITE\_ALLOW\_WRITE | Number of all internal read normal locks. | | SUM\_TIMER\_WRITE\_ALLOW\_WRITE | Total wait time of all internal write allow write locks that are timed. | | MIN\_TIMER\_WRITE\_ALLOW\_WRITE | Minimum wait time of all internal write allow write locks that are timed. | | AVG\_TIMER\_WRITE\_ALLOW\_WRITE | Average wait time of all internal write allow write locks that are timed. | | MAX\_TIMER\_WRITE\_ALLOW\_WRITE | Maximum wait time of all internal write allow write locks that are timed. | | COUNT\_WRITE\_CONCURRENT\_INSERT | Number of all internal concurrent insert write locks. | | SUM\_TIMER\_WRITE\_CONCURRENT\_INSERT | Total wait time of all internal concurrent insert write locks that are timed. | | MIN\_TIMER\_WRITE\_CONCURRENT\_INSERT | Minimum wait time of all internal concurrent insert write locks that are timed. | | AVG\_TIMER\_WRITE\_CONCURRENT\_INSERT | Average wait time of all internal concurrent insert write locks that are timed. | | MAX\_TIMER\_WRITE\_CONCURRENT\_INSERT | Maximum wait time of all internal concurrent insert write locks that are timed. | | COUNT\_WRITE\_DELAYED | Number of all internal write delayed locks. | | SUM\_TIMER\_WRITE\_DELAYED | Total wait time of all internal write delayed locks that are timed. | | MIN\_TIMER\_WRITE\_DELAYED | Minimum wait time of all internal write delayed locks that are timed. | | AVG\_TIMER\_WRITE\_DELAYED | Average wait time of all internal write delayed locks that are timed. | | MAX\_TIMER\_WRITE\_DELAYED | Maximum wait time of all internal write delayed locks that are timed. | | COUNT\_WRITE\_LOW\_PRIORITY | Number of all internal write low priority locks. | | SUM\_TIMER\_WRITE\_LOW\_PRIORITY | Total wait time of all internal write low priority locks that are timed. | | MIN\_TIMER\_WRITE\_LOW\_PRIORITY | Minimum wait time of all internal write low priority locks that are timed. | | AVG\_TIMER\_WRITE\_LOW\_PRIORITY | Average wait time of all internal write low priority locks that are timed. | | MAX\_TIMER\_WRITE\_LOW\_PRIORITY | Maximum wait time of all internal write low priority locks that are timed. | | COUNT\_WRITE\_NORMAL | Number of all internal write normal locks. | | SUM\_TIMER\_WRITE\_NORMAL | Total wait time of all internal write normal locks that are timed. | | MIN\_TIMER\_WRITE\_NORMAL | Minimum wait time of all internal write normal locks that are timed. | | AVG\_TIMER\_WRITE\_NORMAL | Average wait time of all internal write normal locks that are timed. | | MAX\_TIMER\_WRITE\_NORMAL | Maximum wait time of all internal write normal locks that are timed. | | COUNT\_WRITE\_EXTERNAL | Number of all external write locks. | | SUM\_TIMER\_WRITE\_EXTERNAL | Total wait time of all external write locks that are timed. | | MIN\_TIMER\_WRITE\_EXTERNAL | Minimum wait time of all external write locks that are timed. | | AVG\_TIMER\_WRITE\_EXTERNAL | Average wait time of all external write locks that are timed. | | MAX\_TIMER\_WRITE\_EXTERNAL | Maximum wait time of all external write locks that are timed. | You can [TRUNCATE](/docs/server/reference/sql-statements/table-statements/truncate-table.md) the table, which will reset all counters to zero. *This page is licensed: CC BY-SA / Gnu FDL* {% @marketo/form formId="4316" %}