24.32.15 The INFORMATION_SCHEMA INNODB_METRICS Table
INNODB_METRICS table provides 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, set one of the system variables
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
For usage information, see Section 14.16.6, “InnoDB INFORMATION_SCHEMA Metrics Table”.
INNODB_METRICS table has these columns:
A unique name for the counter.
The aspect of
InnoDBthat the metric applies to.
The value since the counter was enabled.
The maximum value since the counter was enabled.
The minimum value since the counter was enabled.
The average value since the counter was enabled.
The counter value since it was last reset. (The
_RESETcolumns 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
MAX_COUNT, and so on.)
The maximum counter value since it was last reset.
The minimum counter value since it was last reset.
The average counter value since it was last reset.
The timestamp of the last start.
The timestamp of the last stop.
The elapsed time in seconds since the counter started.
The timestamp of the last reset.
Whether the counter is still running (
enabled) or stopped (
Whether the item is a cumulative counter, or measures the current value of some resource.
The counter description.
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
You must have the
PROCESSprivilege to query this table.
COUNTvalues may differ from the number of transaction events reported in Performance Schema
InnoDBcounts only those transactions that it executes, whereas Performance Schema collects events for all non-aborted transactions initiated by the server, including empty transactions.