Re: UPDATE with JOIN not using index

Le 16/03/2010 16:02, tv@fuzzy.cz a écrit :
>>  I will try increasing work_mem, but it is already set at 16MB which I
>>  found is quite high.
>
> What do you mean by "high"? I believe the proper value of work_mem is such
> that results in highest performance of the query while not causing
> problems to the other sessions.

Yes, that's true, see my answer below.

> Don't forget you can set this for each session separately (SET work_mem =
> something) so you can use some conservative value in the postgresql.conf
> and use a different value (e.g. 64MB) for batch processing. I guess you
> don't perform such UPDATE in usual sessions, right?

Indeed, I did NOT know that I could set work_mem for each session !
That makes a big difference actually !

I'll try this ASAP !
Thanks a lot for the hint !

Regards,
Arnaud