From: "Anibal David Acosta" <aa@devshock.com>
To: "'Claudio Freire'" <klaussfreire@gmail.com>,
	"'Jeff Janes'" <jeff.janes@gmail.com>
Cc: <pgsql-performance@postgresql.org>
References: <005701cda238$ba4d0350$2ee709f0$@devshock.com>
	<CAMkU=1x_tM6ujEY39FUk=Lj2=NoT+-vJzoFMtwuKPN8Jd5PqrQ@mail.gmail.com>
	<CAGTBQpbK3K56Jzx_xU3ch1QB2TcnbwmQUd0T_98V6BoScGHOMg@mail.gmail.com>
In-Reply-To: 
 <CAGTBQpbK3K56Jzx_xU3ch1QB2TcnbwmQUd0T_98V6BoScGHOMg@mail.gmail.com>
Subject: Re: how to avoid deadlock on masive update with multiples delete
Date: Fri, 5 Oct 2012 14:33:49 -0400
Message-ID: <011201cda327$f99d73b0$ecd85b10$@devshock.com>
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Process 1 (massive update): update table A set column1=0, column2=0 

Process 2 (multiple delete): perform delete_row(user_name, column1, column2)
from table A where user_name=YYY

The pgsql function delete_row delete the row and do other business logic not
related to table A.


-----Mensaje original-----
De: Claudio Freire [mailto:klaussfreire@gmail.com] 
Enviado el: viernes, 05 de octubre de 2012 10:27 a.m.
Para: Jeff Janes
CC: Anibal David Acosta; pgsql-performance@postgresql.org
Asunto: Re: [PERFORM] how to avoid deadlock on masive update with multiples
delete

On Thu, Oct 4, 2012 at 1:10 PM, Jeff Janes <jeff.janes@gmail.com> wrote:
> The bulk update could take an Exclusive (not Access Exclusive) lock.
> Or the delete could perhaps be arranged to delete the records in ctid 
> order (although that might still deadlock).  Or you could just repeat 
> the failed transaction.

How do you make pg update/delete records, in bulk, in some particular order?

(ie, without issuing separate queries for each record)