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Re: [HACKERS] Optimizer fails?

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: mimo(at)interdata(dot)com(dot)pl (Michal Mosiewicz)
Cc: hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Optimizer fails?
Date: 1998-03-25 05:33:15
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackers
> Seq Scan on log  (cost=105832.15 size=699588 width=62)
> There is an index on log table, dt field. The index is b-tree.
> However it doesn't seem to be used. (Of course I have vacuumed it). The
> table has about 2M records. I don't think that Seq Scan is a good idea.
> Also, what if I agregate it on dt field to count(*) or sum some values.
> It would be sequentially scanned, then sorted, then grouped and finally
> agregated, right?

I assume you have vacuum analyze too?  It may help.

Bruce Momjian                          |  830 Blythe Avenue
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