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MySQL 9.4 Reference Manual  / ...  / INFORMATION_SCHEMA Tables  / INFORMATION_SCHEMA InnoDB Tables  /  The INFORMATION_SCHEMA INNODB_METRICS Table

28.4.21 The INFORMATION_SCHEMA INNODB_METRICS Table

TheINNODB_METRICS table provides a wide variety ofInnoDB performance information, complementing the specific focus areas of the Performance Schema tables forInnoDB. With simple queries, you can check the overall health of the system. With more detailed queries, you can diagnose issues such as performance bottlenecks, resource shortages, and application issues.

Each monitor represents a point within theInnoDB source code that is instrumented to gather counter information. Each counter can be started, stopped, and reset. You can also perform these actions for a group of counters using their common module name.

By default, relatively little data is collected. To start, stop, and reset counters, set one of the system variablesinnodb_monitor_enable,innodb_monitor_disable,innodb_monitor_reset, orinnodb_monitor_reset_all, using the name of the counter, the name of the module, a wildcard match for such a name using the“%” character, or the special keywordall.

For usage information, seeSection 17.15.6, “InnoDB INFORMATION_SCHEMA Metrics Table”.

TheINNODB_METRICS table has these columns:

  • NAME

    A unique name for the counter.

  • SUBSYSTEM

    The aspect ofInnoDB that the metric applies to.

  • COUNT

    The value since the counter was enabled.

  • MAX_COUNT

    The maximum value since the counter was enabled.

  • MIN_COUNT

    The minimum value since the counter was enabled.

  • AVG_COUNT

    The average value since the counter was enabled.

  • COUNT_RESET

    The counter value since it was last reset. (The_RESET columns act like the lap counter on a stopwatch: you can measure the activity during some time interval, while the cumulative figures are still available inCOUNT,MAX_COUNT, and so on.)

  • MAX_COUNT_RESET

    The maximum counter value since it was last reset.

  • MIN_COUNT_RESET

    The minimum counter value since it was last reset.

  • AVG_COUNT_RESET

    The average counter value since it was last reset.

  • TIME_ENABLED

    The timestamp of the last start.

  • TIME_DISABLED

    The timestamp of the last stop.

  • TIME_ELAPSED

    The elapsed time in seconds since the counter started.

  • TIME_RESET

    The timestamp of the last reset.

  • STATUS

    Whether the counter is still running (enabled) or stopped (disabled).

  • TYPE

    Whether the item is a cumulative counter, or measures the current value of some resource.

  • COMMENT

    The counter description.

Example

mysql> SELECT * FROM INFORMATION_SCHEMA.INNODB_METRICS WHERE NAME='dml_inserts'\G*************************** 1. row ***************************           NAME: dml_inserts      SUBSYSTEM: dml          COUNT: 3      MAX_COUNT: 3      MIN_COUNT: NULL      AVG_COUNT: 0.046153846153846156    COUNT_RESET: 3MAX_COUNT_RESET: 3MIN_COUNT_RESET: NULLAVG_COUNT_RESET: NULL   TIME_ENABLED: 2014-12-04 14:18:28  TIME_DISABLED: NULL   TIME_ELAPSED: 65     TIME_RESET: NULL         STATUS: enabled           TYPE: status_counter        COMMENT: Number of rows inserted

Notes

  • You must have thePROCESS privilege to query this table.

  • Use theINFORMATION_SCHEMACOLUMNS table or theSHOW COLUMNS statement to view additional information about the columns of this table, including data types and default values.

  • Transaction counterCOUNT values may differ from the number of transaction events reported in Performance SchemaEVENTS_TRANSACTIONS_SUMMARY tables.InnoDB counts only those transactions that it executes, whereas Performance Schema collects events for all non-aborted transactions initiated by the server, including empty transactions.