Re: "slow" queries

From: Brian Cox <brian(dot)cox(at)ca(dot)com>
To: "Tom Lane [tgl(at)sss(dot)pgh(dot)pa(dot)us]" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: "slow" queries
Date: 2009-03-02 20:36:33
Message-ID: 49AC4351.8050307@ca.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

Tom Lane [tgl(at)sss(dot)pgh(dot)pa(dot)us] wrote:
> Well, that's certainly a sufficient reason, if perhaps not the only
> reason. Dropping ts_defects_20090227 will require removal of FK triggers
> on ts_transets, and we can't do that concurrently with transactions that
> might be trying to fire those triggers.
>
> Now admittedly, it would probably be sufficient to take ExclusiveLock
> rather than AccessExclusiveLock when removing triggers, since we do not
> have triggers ON SELECT. Right now though, we just take
> AccessExclusiveLock for most any DDL on a table. There was a patch
> submitted last fall to reduce DDL locking in some cases, but it hasn't
> been reworked to fix the problems that were pointed out (and I
> disremember if it addressed DROP TRIGGER in particular anyway).
>
> regards, tom lane

Thanks for furthering my understanding of postgres (and probably other
SQL servers as well). I can fix this problem easily.

Brian

Browse pgsql-performance by date

  From Date Subject
Next Message Tim Bunce 2009-03-02 21:24:33 Re: "slow" queries
Previous Message Tom Lane 2009-03-02 20:11:07 Re: "slow" queries