On Wed, 29 Oct 2003, Rob Nagler wrote:
> Greg Stark writes:
> > > > SELECT a, (SELECT name FROM t2 WHERE t2.f2 = t1.f2)
> > > > FROM t1
> > > > GROUP BY f2
> > >
> > > This doesn't solve the problem. It's the GROUP BY that is doing the
> > > wrong thing. It's grouping, then aggregating.
> >
> > But at least in the form above it will consider using an index on f2, and it
> > will consider using indexes on t1 and t2 to do the join.
>
> There are 20 rows in t2, so an index actually slows down the join.
> I had to drop the index on t1.f2, because it was trying to use it
> instead of simply sorting 20 rows.
t2 was 'vacuum full'ed and analyzed, right? Just guessing.
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