21.29.19 The INFORMATION_SCHEMA INNODB_METRICS Table

This INFORMATION_SCHEMA table presents a wide variety of InnoDB performance information, complementing the specific focus areas of the PERFORMANCE_SCHEMA tables for InnoDB. 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 the InnoDB 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, you set one of the configuration options innodb_monitor_enable, innodb_monitor_disable, innodb_monitor_reset, or innodb_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 keyword all.

For usage information, see Section 14.14.6, “InnoDB INFORMATION_SCHEMA Metrics Table”.

Table 21.21 INNODB_METRICS Columns

Column nameDescription
NAMEUnique name for the counter.
SUBSYSTEMThe aspect of InnoDB that the metric applies to. See the list following the table for the corresponding module names to use with the SET GLOBAL syntax.
COUNTValue since the counter is enabled.
MAX_COUNTMaximum value since the counter is enabled.
MIN_COUNTMinimum value since the counter is enabled.
AVG_COUNTAverage value since the counter is enabled.
COUNT_RESETCounter value since it was last reset. (The _RESET fields act like the lap counter on a stopwatch: you can measure the activity during some time interval, while the cumulative figures are still available in the COUNT, MAX_COUNT, and so on fields.)
MAX_COUNT_RESETMaximum counter value since it was last reset.
MIN_COUNT_RESETMinimum counter value since it was last reset.
AVG_COUNT_RESETAverage counter value since it was last reset.
TIME_ENABLEDTimestamp of last start.
TIME_DISABLEDTimestamp of last stop.
TIME_ELAPSEDElapsed time in seconds since the counter started.
TIME_RESETTimestamp of last stop.
STATUSWhether the counter is still running () or stopped ().
TYPEWhether the item is a cumulative counter, or measures the current value of some resource.
COMMENTCounter 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: 3
MAX_COUNT_RESET: 3
MIN_COUNT_RESET: NULL
AVG_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
1 row in set (0.00 sec)

Notes: