Re: BUG #2225: Backend crash -- BIG table

On Fri, 3 Feb 2006, Patrick Rotsaert wrote:

>
> >One question is what does the explain (without analyze) plan look like for
> >the above and are the row estimates valid in the case of one of the hash
> >plans.
> >
> >
> pointspp=# explain select trid, count(*) from pptran group by trid
> having count(*) > 1;
>                                 QUERY PLAN
> --------------------------------------------------------------------------
>  HashAggregate  (cost=1311899.28..1311902.78 rows=200 width=18)
>    Filter: (count(*) > 1)
>    ->  Seq Scan on pptran  (cost=0.00..1039731.02 rows=36289102 width=18)
> (3 rows)

Hmm, if you do an enable_hashagg=false and then run the query (without
explain) does it work then?

> >Failing that, how many rows should the above return?
> >
> >
> That is exactly what I am trying to find out. I can only guess that, but
> it should not be more than a couple of 10k rows.

Okay, so it's unlikely to be a client side memory issue (if it were
returning alot of rows, that could also be an issue).