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 14.15.6, “InnoDB INFORMATION_SCHEMA Metrics Table”.
Table 21.15 INNODB_METRICS Columns
| Column name | Description |
|---|---|
NAME | Unique name for the counter. |
SUBSYSTEM | The 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. |
COUNT | Value since the counter is enabled. |
MAX_COUNT | Maximum value since the counter is enabled. |
MIN_COUNT | Minimum value since the counter is enabled. |
AVG_COUNT | Average value since the counter is enabled. |
COUNT_RESET | Counter 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_RESET | Maximum counter value since it was last reset. |
MIN_COUNT_RESET | Minimum counter value since it was last reset. |
AVG_COUNT_RESET | Average counter value since it was last reset. |
TIME_ENABLED | Timestamp of last start. |
TIME_DISABLED | Timestamp of last stop. |
TIME_ELAPSED | Elapsed time in seconds since the counter started. |
TIME_RESET | Timestamp of last stop. |
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 | 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: 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
Notes:
You must have the PROCESS
privilege to query this table.
Use DESCRIBE or
SHOW COLUMNS to view additional
information about the columns of this table including data
types and default values.