CATEGORIES.TXT

MySQL Metric Categories
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The New Relic plugin is an extensible architecture, allowing you to define your
own new MySQL metrics that can be obtained via an SQL statement.  As new MySQL 
versions are released, or with additional MySQL third-party storage engines 
additional information is available for gathering and instrumenting.

Providing an SQL statement can return either a set of rows of key/value results,
or return a single row of many columns with a single value, and those values are 
numeric (a New Relic limitation), the MySQL plugin can record this information 
in New Relic.

The config/metric.category.json file includes the default categories of MySQL metrics
and provides some additional examples for reference.

The obvious commands SHOW GLOBAL STATUS, SHOW MASTER STATUS and SHOW SLAVE STATUS 
satisfy the previous formatting requirements. Additionally commands that select
information from the INFORMATION_SCHEMA, PERFORMANCE_SCHEMA or other tables are possible,
for example in MySQL 5.5 SELECT * FROM INFORMATION_SCHEMA.innodb_buffer_pool_stats and
in MySQL 5.6 SELECT name, count FROM INFORMATION_SCHEMA.innodb_metrics provide additional
information. 

The JSON attributes are:

* category  - The description in the metric names
* SQL       - The SQL statement
* result    - "row", "set", or "special"
* value_metrics - A CSV list of metrics that are values
* counter_metrics - A CSV list of metrics that are per second values

Sample list of available metrics:

* status              - general status metrics
* master              - master status metrics
* slave               - slave status metrics including replication metrics
* buffer_pool_stats   - buffer pool status metrics
* innodb_status       - innodb status metrics
* innodb_metrics      - innodb information metrics
* innodb_mutex        - innodb mutex metrics

Note: The innodb_mutex metric category can lead to increased memory usage for the plugin 
if the monitored database is under a high level of contention (i.e. large numbers of active mutexes).

Currently, the New Relic Platform does not allow for customized dashboards per user.
In the future this feature will enable custom categories to be fully utilized.