Re: How to track number of connections and hosts to Postgres cluster - Mailing list pgsql-performance

From Adarsh Sharma
Subject Re: How to track number of connections and hosts to Postgres cluster
Date
Msg-id 4E54DBDE.9030000@orkash.com
Whole thread Raw
In response to Re: How to track number of connections and hosts to Postgres cluster  (Venkat Balaji <venkat.balaji@verse.in>)
Responses Re: How to track number of connections and hosts to Postgres cluster
List pgsql-performance
pg_stat_activity keeps track of all this information.

select * from pg_stat_activity where datname='databasename';



Venkat Balaji wrote:
Thanks Guillaume !!

But, if put log_connections to on and log_disconnections to on wouldn't the Postgres be logging in lot of data ?

Will this not be IO intensive ? I understand that this is the best way, but, would want to know if there is an other way to reduce IO ( may be through queries to catalog tables ).

Thanks
Venkat

On Wed, Aug 24, 2011 at 1:19 PM, Guillaume Lelarge <guillaume@lelarge.info> wrote:
On Wed, 2011-08-24 at 13:05 +0530, Venkat Balaji wrote:
> Hello Everyone,
>
> I am working on an alert script to track the number of connections with the
> host IPs to the Postgres cluster.
>
> 1. I need all the host IPs making a connection to Postgres Cluster (even for
> a fraction of second).

You should set log_connections to on.

> 2. I would also want to track number of IDLE connections, IDLE IN
> TRANSACTION connections and length of the connections as well.
>

IDLE and IDLE in transactions are the kind of informations you get in
pg_stat_activity.

Length of connections, you can get it with log_disconnections.

> I would be making use of pg_stat_activity and also thought of enabling
> logging the host ips in the db server log files which seems to be expensive
> for me (in terms of IO and logfile size).
>

Using pg_stat_activity won't get you really small connections. You need
log_connections for that, and log_disconnections for the duration of
connections. So you'll have to work on a tool that could get some
informations with queries on pg_stat_activity, and that could read
PostgreSQL log files.


--
Guillaume
 http://blog.guillaume.lelarge.info
 http://www.dalibo.com



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