AW: Re: Performance degradation in PostgreSQL 7.1beta3 vs 6.5.3

From: Zeugswetter Andreas SB <ZeugswetterA(at)wien(dot)spardat(dot)at>
To: "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, bruc(at)acm(dot)org
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: AW: Re: Performance degradation in PostgreSQL 7.1beta3 vs 6.5.3
Date: 2001-01-17 09:10:23
Message-ID: 11C1E6749A55D411A9670001FA6879633681B9@sdexcsrv1.f000.d0188.sd.spardat.at
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> > More importantly, PostgreSQL 6.5.3 works very, very well without
> > VACUUM'ing.
>
> 6.5 effectively assumes that "foo = constant" will select exactly one
> row, if it has no statistics to prove otherwise.

I thought we had agreed upon a default that would still use
the index in the above case when no statistics are present.
Wasn't it something like a 5% estimate ? I did check
that behavior, since I was very concerned about that issue.
Now, what is so different in his case?

Andreas

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