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25.39.22 The INFORMATION_SCHEMA INNODB_METRICS Table
The 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_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 15.14.6, “InnoDB INFORMATION_SCHEMA Metrics Table”.
The INNODB_METRICS
table has these
columns:
NAME
A unique name for the counter.
SUBSYSTEM
The aspect of
InnoDB
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
- *************************** 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 the
INFORMATION_SCHEMA
COLUMNS
table or theSHOW COLUMNS
statement to view additional information about the columns of this table, including data types and default values.Transaction counter
COUNT
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.
Document created the 26/06/2006, last modified the 26/10/2018
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