<#import "/templates/guide.adoc" as tmpl>
<#import "/templates/links.adoc" as links>

<@tmpl.guide
title="{project_name} Database Metrics"
summary="Learn about metrics describing {project_name}'s connection to the database"
tileVisible="false"
>

<#include "partials/prerequisites-metrics-troubleshooting.adoc" />

== Database connection pool metrics

Configure {project_name} to use a fixed size database connection pool.
See the <@links.ha id="concepts-database-connections"/> {section} for more information.

[TIP]
====
If there is a high count of threads waiting for a database connection, increasing the database connection pool size is not always the best option. It might overload the database which would then become the bottleneck. Consider the following options instead:

* Reduce the number of HTTP worker threads using the option `http-pool-max-threads` to make it match the available database connections, and thereby reduce contention and resource usage in {project_name} and increase throughput.
* Check which database statements are executed on the database. If you see, for example, a lot of information about clients and groups being fetched, and the `users` and `realms` cache are full, this might indicate that it is time to increase the sizes of those caches and see if this reduces your database load.
====

|===
|Metric |Description

m| agroal_available_count
| Idle database connections.

m| agroal_active_count
| Database connections used in ongoing transactions.

m| agroal_awaiting_count
| Threads waiting for a database connection to become available.

|===

== Next steps

Return back to the <@links.observability id="metrics-for-troubleshooting"/> or proceed to <@links.observability id="metrics-for-troubleshooting-http"/>.

</@tmpl.guide>
