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

[Mike Leahy]

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.
>