From: | "Milen Kulev" <makulev(at)gmx(dot)net> |
---|---|
To: | "'Jim C(dot) Nasby'" <jnasby(at)pervasive(dot)com>, "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Partitioning... |
Date: | 2006-06-14 11:47:12 |
Message-ID: | 010801c68fa8$46744320$0a00a8c0@trivadis.com |
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Thread: | |
Lists: | pgsql-general |
Aha !!!
Thanks Jim, the "trick" worked for me !
Regards. Milen
-----Original Message-----
From: Jim C. Nasby [mailto:jnasby(at)pervasive(dot)com]
Sent: Wednesday, June 14, 2006 1:09 AM
To: Tom Lane
Cc: Milen Kulev; pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] Partitioning...
On Mon, Jun 12, 2006 at 06:58:06PM -0400, Tom Lane wrote:
> "Milen Kulev" <makulev(at)gmx(dot)net> writes:
> > What is wrong with random() ?
>
> Not guaranteed to be stable across the multiple evaluations that the
> rule will perform ... remember a rule is a macro and has the usual
> multiple-evaluation gotchas in the face of volatile arguments.
I believe a safe alternative would be...
INSERT INTO ... SELECT * FROM
(SELECT random()*20 FROM ...)
;
You might need to add an ORDER BY to the subquery to ensure PostgreSQL doesn't pull it into the main query.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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