[collectd] how to set a threshold using postgresql plugin

[Gerardo Herzig]

Thank you very much for your time, Marc. I didnt try your proposal yet, but the wiki entry looks like having the kind of knowledge i was needing to solve the situation.

Thanks again!

Gerardo

----- Mensaje original -----
> De: "Marc Fournier" <marc.fournier at camptocamp.com>
> Para: "Gerardo Herzig" <gherzig at fmed.uba.ar>, "collectd" <collectd at verplant.org>
> Enviados: Viernes, 11 de Marzo 2016 6:10:53
> Asunto: Re: [collectd] how to set a threshold using postgresql plugin
> 
> Gerardo Herzig <gherzig at fmed.uba.ar> writes:
> 
> > Hi all. Im sending collectd values from a postgres DB to our
> > collectd central server.
> > In DB, there is using postgres plugin like:
> >
> > <Query db_movements>
> >   Statement "select sum(numbackends) as backends, sum(tup_inserted)
> >   as inserts, sum(tup_updated) as updates, sum(tup_deleted) as
> >   deletes
> >   from pg_stat_database;"
> >   <Result>
> >     Type gauge
> >     InstancePrefix total_backends
> >     ValuesFrom "backends"
> >   </Result>
> > </Query>
> > <Database template1>
> >         Interval 10
> >         Host localhost
> >         User postgres
> >         Query db_movements
> > </Database>
> >
> > And, in the "central" collectd server i want to set a threshold for
> > that server, so
> > " If that db server is over 100 connections in use, ALERT "
> >
> > At that point, i got confused about how to get it work.
> > I have something like that:
> >
> > <Host "db_server">
> >     <Plugin "postgresql-template1">
> >       <Instance "total_backends">
> >         FailureMax 100.0
> >       </Instance>
> >     </Plugin>
> >  </Host>
> >
> >
> > It throws no error, but even if i put a FailureMax of 2 or so,
> > alert is not raising.
> > So, anyone can help me to know to set that alert?
> 
> I don't think the above specification will match the value you're
> trying
> to track.
> 
> Try something like this:
> 
> <Host "db_server">
>   <Plugin "postgresql">
>     Instance "template1"
>     <Type "gauge">
>       Instance "total_backends"
>       FailureMax 100.0
>     </Type>
>   </Plugin>
> </Host>
> 
> You might want to enable the unixsock plugin and run
> "collectdctl listval" to make sure your specification actually
> matches
> an existing element name.
> 
> Also, take a look at
> https://collectd.org/wiki/index.php/Naming_schema
> 
> Marc
>