Implementation of UPDATE - Mailing list pgsql-general

From Diogo Biazus
Subject Implementation of UPDATE
Date
Msg-id 3D6288E3.4060001@ikono.com.br
Whole thread Raw
Responses Re: Implementation of UPDATE  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
Hi folks,

I was wondering if postgres executes a subquery in an UPDATE clause once
and use the result (of the subquery) for all the updates.

Example:
UPDATE table SET field1 = (SELECT field2 FROM table2 WHERE field3 = '123')

Sorry if it seems to be a stupid question, but sometimes this kind of
update is so slow in my server, that makes me suspicious.

TIA

--
Diogo de Oliveira Biazus
diogo@ikono.com.br
Ikono Sistemas e Automação
http://www.ikono.com.br



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