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Re: Slow delete times??

From: "Octavio Alvarez" <alvarezp(at)alvarezp(dot)ods(dot)org>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Slow delete times??
Date: 2004-01-25 02:12:42
Message-ID: 2150.192.168.0.64.1074996762.squirrel@alvarezp.ods.org (view raw or flat)
Thread:
Lists: pgsql-performance

First of, thanks, Tom.

Although I've been very careful on this kind of things, looks like I
missed one index on a referencing column. Still, I don't allow an entire
delete of a table if it has referencing columns with values, so at the
moment of the deletion, it has no rows at all.

I checked datatype mismatches, and there are none. All my FKs are
integers, like the referenced column of the referenced table.

I was thinking on dropping the indexes before doing the deletes, but
Joshua suggested using TRUNCATE instead.

Thanks.
Octavio.

Tom Lane said:
> "Octavio Alvarez" <alvarezp(at)alvarezp(dot)ods(dot)org> writes:
>> Please tell me if this timing makes sense to you for a Celeron 433 w/
RAM=256MB dedicated testing server. I expected some slowness, but not
this
>> high.
>
> I'll bet you have foreign keys referencing this table, and the
> referencing columns do not have indexes.  PG will let you do that ...
but it makes updates and deletes horribly slow.  You generally want to
add those indexes.
>
> If they *are* indexed, check for datatype mismatches.  That's
> another thing that kills performance ...
>
> 			regards, tom lane
>


-- 
Octavio Alvarez Piza.
E-mail: alvarezp(at)alvarezp(dot)ods(dot)org



-- 
Octavio Alvarez Piza.
E-mail: alvarezp(at)alvarezp(dot)ods(dot)org

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