Re: DELETE with LIMIT (or my first hack)

From: Rob Wultsch <wultsch(at)gmail(dot)com>
To: Marti Raudsepp <marti(at)juffo(dot)org>
Cc: Jaime Casanova <jaime(at)2ndquadrant(dot)com>, Daniel Loureiro <loureirorg(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: DELETE with LIMIT (or my first hack)
Date: 2010-11-30 13:26:37
Message-ID: AANLkTinuw5XhpMMb6quthPZ99zQmBEr5ew6be7iJ52Z=@mail.gmail.com
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On Mon, Nov 29, 2010 at 10:50 PM, Marti Raudsepp <marti(at)juffo(dot)org> wrote:
> On Tue, Nov 30, 2010 at 05:09, Jaime Casanova <jaime(at)2ndquadrant(dot)com> wrote:
>> at least IMHO the only sensible way that LIMIT is usefull is with
>> an ORDER BY clause with make the results very well defined...
>
> DELETE with LIMIT is also useful for deleting things in batches, so
> you can do large deletes on a live system without starving other users
> from I/O. In this case deletion order doesn't matter (it's more
> efficient to delete rows in physical table order) -- ORDER BY isn't
> necessary.
>
> Regards,
> Marti
>

++

I have a lot of DELETE with LIMIT in my (mysql) environment for this reason.

--
Rob Wultsch
wultsch(at)gmail(dot)com

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