Installation¶

Scalability Metrics plugin is shipped with Percona Server for MySQL, but it is not installed by default. To enable the plugin you must run the following command:

INSTALL PLUGIN scalability_metrics SONAME 'scalability_metrics.so';

You can check if the plugin is loaded correctly by running:

SHOW PLUGINS;

The plugin should be listed in the output:

+--------------------------------+----------+--------------------+------------------------+---------+
| Name                           | Status   | Type               | Library                | License |
+--------------------------------+----------+--------------------+------------------------+---------+
...
| scalability_metrics            | ACTIVE   | AUDIT              | scalability_metrics.so | GPL     |
+--------------------------------+----------+--------------------+------------------------+---------+

System Variables¶

variable scalability_metrics_control¶

Command Line:	Yes
Scope:	Global
Dynamic:	Yes
Variable Type:	String
Default Value:	OFF
Values:	OFF, ON, RESET

This variable can be used to enable and disable the collection of metrics for scalability measurement. By setting the value to RESET all counters will be reset while continuing to count metrics.

Status Variables¶

variable scalability_metrics_elapsedtime¶

Variable Type:	Numeric

This status variable shows total time elapsed, in microseconds, since metrics collection was started.

variable scalability_metrics_queries¶

Variable Type:	Numeric

This status variable shows number of completed queries since metrics collection was started.

variable scalability_metrics_concurrency¶

Variable Type:	Numeric

This status variable shows number of queries currently executed.

variable scalability_metrics_totaltime¶

Variable Type:	Numeric

This status variable shows total execution time of all queries, including the in-progress time of currently executing queries, in microseconds (ie. if two queries executed with 1 second of response time each, the result is 2 seconds).

variable scalability_metrics_busytime¶

Variable Type:	Numeric

This counter accounts the non-idle server time, that is, time when at least one query was executing.

Version Specific Information¶

• 5.7.10-1 Feature ported from Percona Server for MySQL 5.6
• 5.7.16-10 Feature has been deprecated.

Other Reading¶

• Fundamental performance and scalability instrumentation
• Forecasting MySQL Scalability with the Universal Scalability Law Whitepaper