| From: | Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> |
|---|---|
| To: | Ives Landrieu <ives(dot)landrieu(at)ua(dot)ac(dot)be> |
| Cc: | <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Strange cost computation? |
| Date: | 2002-10-30 16:12:12 |
| Message-ID: | 20021030081123.H31599-100000@megazone23.bigpanda.com |
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| Lists: | pgsql-hackers |
On Wed, 30 Oct 2002, Stephan Szabo wrote:
> On 29 Oct 2002, Ives Landrieu wrote:
>
> > Hi,
> >
> > Can anybody explain the following results when using EXPLAIN,
> > one time with enable_seqscan=on and one time with enable_seqscan=off.
> > What I don't understand is that the nodes created are the same
> > (index scan, seq scan), but the costs differ.
>
> Enable seq scan actually just sets a large cost disbenefit to seq scans.
Boy, that sentence sure didn't make sense. enable_seqscan=off actually
gives a large cost disbenefit to seqscans.
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