Technical details
=================

Here are some technical details that might be interesting for those who are planning to use pgwatch2 for critical monitoring tasks
or customize it in some way.

* Dynamic management of monitored databases, metrics and their intervals - no need to restart/redeploy

  Config DB or YAML / SQL files are scanned every 2 minutes (by default, changeable via \-\-servers-refresh-loop-seconds)
  and changes are applied dynamically. As common connectivity errors also also handled, there should be no need to restart
  the gatherer "for fun". Please always report issues which require restarting.

* There are some safety features built-in so that monitoring would not obstruct actual operation of databases

  * Up to 2 concurrent queries per monitored database (thus more per cluster) are allowed

  * Configurable statement timeouts per DB

  * SSL connections support for safe over-the-internet monitoring (use "-e PW2_WEBSSL=1 -e PW2_GRAFANASSL=1" when launching Docker)

  * Optional authentication for the Web UI and Grafana (by default freely accessible)

* Instance-level metrics caching

  To further reduce load on multi-DB instances, pgwatch2 can cache the output of metrics that are marked to gather only
  instance-level data. One such metric is for example "wal", and the *metric attribute* is "is_instance_level".
  Caching will by activated only for *continuous* :ref:`DB types <db_types>`, and to a default limit of up to 30 seconds (changeable via the
  \-\-instance-level-cache-max-seconds param).