RE: [GENERAL] Long update query ?

From: "Taral" <taral(at)mail(dot)utexas(dot)edu>
To: "David Hartwig" <daveh(at)insightdist(dot)com>, "Sergei Chernev" <ser(at)nsu(dot)ru>
Cc: <pgsql-general(at)postgreSQL(dot)org>
Subject: RE: [GENERAL] Long update query ?
Date: 1998-09-28 17:15:01
Message-ID: 000001bdeb03$86c79d20$3b291f0a@taral
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> This is caused by a semi-well known weakness in the optimizer.
> The optimizer
> rewrites the WHERE clause in conjunctive normal form (CNF):
>
> (A and B) or (C and D) ==> (A or C) and (A or D) and (B or C)
> and (B or D)
>

Wouldn't disjunctive normal form be better, since it can be implemented as
the simple union of a set of small queries?

Taral

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