Re: Partitionin with check functions

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От fatih ozturk
Тема Re: Partitionin with check functions
Дата
Msg-id 397285.75133.qm@web111503.mail.gq1.yahoo.com
обсуждение исходный текст
Ответ на Partitionin with check functions  (fatih ozturk <ozturkfa@yahoo.com>)
Список pgsql-admin
Дерево обсуждения
Thank you

"Yes, it does.  It might be worthwile to use

  WHERE sel=123 AND mod(sel,6)=3

I think you could use a rule to add the mod() condition automatically.
"
this is great idea

But the problem is i did not accomplish to find a way to change query like

     partitioning=# select * from mainlog where sel=22;

to
   
     partitioning=# select * from mainlog where sel=22 and mod(sel,6)=4;


"on select" rules just creates views, dont routes the queries.
I cant use tirggers for selects.
Is there exists a way of changing select query before query plan generated?

Any ideas?

I am very appreciative for your answers and interest.

Thanks

--- On Mon, 3/30/09, Harald Fuchs <hari.fuchs@gmail.com> wrote:

From: Harald Fuchs <hari.fuchs@gmail.com>
Subject: Re: [ADMIN] Partitionin with check functions
To: pgsql-admin@postgresql.org
Date: Monday, March 30, 2009, 4:08 PM

In article <2499.1238420859@sss.pgh.pa.us>,
Tom Lane <tgl@sss.pgh.pa.us> writes:

> In particular, a constraint like "sel=123" is *not* going to lead the
> planner to draw any conclusions about the value of "mod(sel,6)".
> Now, if you'd written "WHERE mod(sel,6)=3", I think it would draw
> the right conclusions.

Yes, it does.  It might be worthwile to use

  WHERE sel=123 AND mod(sel,6)=3

I think you could use a rule to add the mod() condition automatically.


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