Re: partitionning

From: Mike Rylander <mrylander(at)gmail(dot)com>
To: Martijn van Oosterhout <kleptog(at)svana(dot)org>, Mike Rylander <mrylander(at)gmail(dot)com>, Christian Kratzer <ck(at)cksoft(dot)de>, pgsql-general(at)postgresql(dot)org
Subject: Re: partitionning
Date: 2005-03-13 00:58:22
Message-ID: b918cf3d05031216583cb0b081@mail.gmail.com
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On Sun, 13 Mar 2005 00:18:39 +0100, Martijn van Oosterhout
<kleptog(at)svana(dot)org> wrote:
> On Sat, Mar 12, 2005 at 08:24:20PM +0000, Mike Rylander wrote:
> > There is now way to have PG completely skip the unused partitions.
> > However, with an index on the "partitioner" column of each partition
> > table PG will basically fall of the end of the index almost
> > imediately, and then use an appropiate plan for the useful partitions.
> > It's not the same as Oracle partitioning, but without expicit Planner
> > work it can't be.
>
> Note, the planner does have most of the intelligence needed to
> determine when it can skip a partition. It has code that can determine
> if the intersection of:
>
> Partition constraint: lower bound < value < upper bound
> Query clause: value [operator] constant
>
> Will be always false or can be true. It's just a matter of getting the
> clause to the right place to make it skip...

I see. I should have qualified my statement with "*as of now* there
is no way". If I felt comfortable digging into the planner I'd offer
to take that on, but...

Thanks for pointing out that detail!

--
Mike Rylander
mrylander(at)gmail(dot)com
GPLS -- PINES Development
Database Developer
http://open-ils.org

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