From: | Anj Adu <fotographs(at)gmail(dot)com> |
---|---|
To: | Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> |
Cc: | pgsql-admin(at)postgresql(dot)org |
Subject: | Re: Pre-creating partitions incurs insert penalty |
Date: | 2009-05-29 02:49:34 |
Message-ID: | f2fd819a0905281949m2c966ec3u55523c613d94b343@mail.gmail.com |
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Lists: | pgsql-admin |
Thanks..I'll rewrite the rules as triggers. Would that in any way impact
constraint exclusion for select statements ?..I assume not.
On Thu, May 28, 2009 at 5:46 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>wrote:
> Yeah, rules have more overhead the more partitions you have, whereas
> triggers do not. If you can switch to triggers you'd like see better
> performance, but be aware that plpgsql is kind of retarded when it
> comes to doing anything fancy with triggers.
>
> On Thu, May 28, 2009 at 6:43 PM, Anj Adu <fotographs(at)gmail(dot)com> wrote:
> > Partitioning is implemented via rules and check constraints to ensure
> > partition integrity.
> >
> > On Thu, May 28, 2009 at 5:21 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
> > wrote:
> >>
> >> On Thu, May 28, 2009 at 5:22 PM, Anj Adu <fotographs(at)gmail(dot)com> wrote:
> >> > I noticed a very strange performance issue after I pre-create daily
> >> > partitions for the next month on a table that has a very large insert
> >> > volume
> >> > (30 million a day). After the partitions are created..the inserts seem
> >> > to
> >> > slow down. I verifiied that this was the issue by dropping the
> >> > partitions...When I dropped the pre-created partitions..the
> performance
> >> > issue disappeared. Looks like you cannot have too many partitions (in
> >> > this
> >> > case..I had a total of 35 partitions when the performance issue was
> >> > noticed)
> >>
> >> How are you enforcing partiitoning on your inserts? Via app
> >> knowledge, triggers, or rules? I'd expect rules might have a penalty
> >> with more partitions, but not expect it from app or trigger based
> >> partitioning.
> >
> >
>
>
>
> --
> When fascism comes to America, it will be intolerance sold as diversity.
>
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