Re: Exact same output - pg_stat_statements

On Mon, Jan 02, 2023 at 02:34:13PM +0100, hubert depesz lubaczewski wrote:
> On Fri, Dec 30, 2022 at 11:04:59AM -0500, Rushikesh socha wrote:
> > Hi, Whenever I am running the below query on one of my Azure PostgreSQL
> > PaaS instances I am getting exact same output. I feel it shows old
> > information but as far as i know pg_stat_statements only shows current
> > information and not past right ? It may be a bug?
>
> pg_stat_statements has all the data since last reset of stats.
>
> So if you never reset stats, it accumulated data for howeve rlong you
> are using pg.
>
> Not really surprising that top total-time uses are the same.
>
> If you want to sensibly use it you should call reset function every now
> and then.

Resetting the data adds some noticeable overhead as newly added entries will
need to generate a normalize query string and so on.  What most people do is
taking regular snapshots of pg_stat_statements (and other stats) view and then
compare the snapshots.  There are a few open source projects doing that
available.