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Re: [HACKERS] RE: [GENERAL] Long update query ? (also Re: [GENERAL] CNF vs. DNF)

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: taral(at)mail(dot)utexas(dot)edu (Taral)
Cc: jwieck(at)debis(dot)com, hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] RE: [GENERAL] Long update query ? (also Re: [GENERAL] CNF vs. DNF)
Date: 1998-10-03 03:01:07
Message-ID: 199810030301.XAA01160@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-hackers
[Charset iso-8859-1 unsupported, filtering to ASCII...]
> > How do we do that with UNION, and return the right rows.  Seems the
> > _join_ happending multiple times would be much worse than the factoring.
> 
> Ok... We have two problems:
> 
> 1) DNF for unjoined queries.
> 2) Factorization for the rest.
> 
> I have some solutions for (1). Not for (2). Remember that unjoined queries
> are quite common. :)
> 
> For (1), we can always try to parallel the multiple queries... especially in
> the case where a sequential search is required.

I don't know how to return the proper rows with UNION.

-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  maillist(at)candle(dot)pha(dot)pa(dot)us            |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026


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