[postgis-users] Nested loop join = very bad performance

[Mike Leahy]

Mark/List,

I just replaced my postgresql.conf with the default copy that appears in 
/etc/postgresql/8.4/main/ after a fresh install.  The performance is pretty 
much the same as before (maybe even about 400 ms worse than before).

Is there anything else I should try?

Mike

On Monday 29 March 2010 17:35:29 Mike Leahy wrote:
> Hi Mark,
> 
> I don't recall making any changes...at least not until the error I
>  encountered last week cropped up - but I think I reversed those changes (I
>  will double- check tonight).  But I think I have encountered performance
>  problems with this query before on other systems - I had originally
>  dismissed it as hardware limitations I was dealing in my testing system at
>  the time.  After recent hardware upgrades and after dealing with that
>  specific bug, that's when the slow performance of this query really stood
>  out.
> 
> Mike
> 
> On Monday 29 March 2010 07:53:50 Mark Cave-Ayland wrote:
> > Mike Leahy wrote:
> > > Is this something that should be looked into, or should I just
> > > incorporate the workaround of disabling nested loop joins into my code?
> >
> > I find that generally PostgreSQL is fairly good at its estimates unless
> > someone has already tried to tune the database. Have you changed any of
> > the settings in postgresql.conf from their defaults?
> >
> >
> > ATB,
> >
> > Mark.
>