Re: Partitioning...
От | Milen Kulev |
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Тема | Re: Partitioning... |
Дата | |
Msg-id | 010801c68fa8$46744320$0a00a8c0@trivadis.com обсуждение исходный текст |
Ответ на | Re: Partitioning... ("Jim C. Nasby" <jnasby@pervasive.com>) |
Ответы |
Re: Partitioning...
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Список | pgsql-general |
Aha !!! Thanks Jim, the "trick" worked for me ! Regards. Milen -----Original Message----- From: Jim C. Nasby [mailto:jnasby@pervasive.com] Sent: Wednesday, June 14, 2006 1:09 AM To: Tom Lane Cc: Milen Kulev; pgsql-general@postgresql.org Subject: Re: [GENERAL] Partitioning... On Mon, Jun 12, 2006 at 06:58:06PM -0400, Tom Lane wrote: > "Milen Kulev" <makulev@gmx.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@pervasive.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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