Re: [HACKERS] subselect and optimizer

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: boersenspiel(at)vocalweb(dot)de
Cc: hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] subselect and optimizer
Date: 1998-04-11 23:06:15
Message-ID: 199804112306.TAA04449@candle.pha.pa.us
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>
> > > But this patch still didn't help for a simple join without a where
> > > clause. The query plan says it uses two sequential scans, where 6.2.1
> > > uses two index scans.
> >
> > But we didn't have subselcts in 6.2.1?
>
> No, but in the more general case of a simple join over two tables
> with fields with an index declared on them.
>
> say: Select * from Trans, Spieler where
> Spieler.spieler_nr=Trans.spieler_nr
>
> Uses indices in 6.2.1, doesn't use them in 6.3.1 (two seq scans).
>
> I just wanted to remind you, that these problems are not restricted
> to subqueries, but seem to be a more general 'flaw' in 6.3.x .

Ah, but that is fixed in 6.3.2 beta. We particularly waited for a fix
for this before releasing a new beta. But you say you have Vadim's fix
that is in 6.3.2, and it still doesn't work?

--
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