Re: [PERFORM] zero performance on query

2005-10-26 Thread Steinar H. Gunderson
On Wed, Oct 26, 2005 at 08:05:21AM -0400, Merlin Moncure wrote: > select count(*) from fotos f where not exists (select archivo from archivos a > where a.archivo = f.archivo) This was an optimization before 7.4, but probably isn't anymore. /* Steinar */ -- Homepage: http://www.sesse.net/

Re: [PERFORM] zero performance on query

2005-10-26 Thread Merlin Moncure
> look at this: > select count(*) from fotos where archivo not in (select archivo from > archivos) > Aggregate (cost=4899037992.36..4899037992.37 rows=1 width=0) > -> Seq Scan on fotos (cost=22598.78..4899037338.07 rows=261716 width=0) >Filter: (NOT (subplan)) >SubPlan >

Re: [PERFORM] zero performance on query

2005-10-26 Thread Steinar H. Gunderson
On Tue, Oct 25, 2005 at 10:26:43PM -0600, Sidar López Cruz wrote: > look at this: > select count(*) from fotos where archivo not in (select archivo from > archivos) > Aggregate (cost=4899037992.36..4899037992.37 rows=1 width=0) > -> Seq Scan on fotos (cost=22598.78..4899037338.07 rows=261716 wi

Re: [PERFORM] zero performance on query

2005-10-25 Thread Dmitri Bichko
That seems like a pretty horrible way to do that query, given the table sizes. What about something like: SELECT count(*) FROM fotos f LEFT JOIN archivo a USING(archivo) WHERE a.archivo IS NULL Incidentally, can someone explain what the "Materialize" subplan does? Is this new in 8.1? Dmitri