Re: Upgrading from 9.2 to 9.3 causes performance degradation

On 03/24/2014 07:32 PM, Álvaro Nunes Lemos Melo wrote:
> Jeff: I ran a VACUUM FULL ANALYZE and retested. No significative change
> was notices, the explain is availiable in
>
> 9.3 - After VACUUM FULL ANALYZE - http://explain.depesz.com/s/rVoW
> 9.3 - Original - http://explain.depesz.com/s/Vwt
>
> Adrian: I'll try to send the query attached. My doubts are: why 9.3 is
> slower then 9.2 with the same database/configuration/harware/query? Even
> worst, why 9.3 got slower results on a better HW, where 9.2 improved on
> the same scenario.

Yikes, that query is above my level of expertise. Someone with more
knowledge of the planner than I is going to have to go over that. As to
why the change? Best guess, something changed in the planner and this
query is on the wrong side of the change. So are you seeing a general
slowdown or is it restricted to this particular query?

>
> I've just ran the explains on my new server, links below:
> 9.2 - http://explain.depesz.com/s/AeD
> 9.3 - http://explain.depesz.com/s/1sp
>
>
> For comparison sake, old server:
> 9.2 -http://explain.depesz.com/s/bXIo
> 9.3 -http://explain.depesz.com/s/Vwt<http://explain.depesz.com/s/Vwt>
>
> I really appreciate your help.
>
> Thanks again,
>
>
> --
> Álvaro Nunes Melo Atua Sistemas de Informação
> alvaro(at)atua(dot)com(dot)br http://www.atua.com.br
> (54) 9976-0106 (54) 3045-4144

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com