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Re: 10g optimizer and dynamic sampling

From: <p.santos000_at_gmail.com>
Date: 2 Jun 2006 13:30:23 -0700
Message-ID: <1149280223.040146.188060@u72g2000cwu.googlegroups.com>

Mladen Gogala wrote:
> p.santos000_at_gmail.com wrote:
> > Well that's a good point, but here is the difficult thing about this
> > system. Our customers
> > upload data anytime they want at any point of the day. So in the
> > morning COL1='X' could
> > return 100 rows, but the same query in the evenning could yield a
> > million rows.
> >
> > Most of the queries executed on our system take anywhere from 5 minutes
> > to 30-45 minutes, so a couple of extra seconds is for the sampling is
> > insignificant.
> >
> > -peter
> >
>
>
> Peter, if that is Oracle 9i you can set tables to "MONITORING", in which
> case DBA_TAB_MODIFICATIONS will be populated and statistics scanned
> dynamically only for the tables with more then 10% of changed rows.
>
>
> --
> Mladen Gogala
> http://www.mgogala.com

This is 10g so the monitoring is done automatically. We also have scheduled jobs that run every 4hrs and look for "stale" objects and re-generate
stats. Received on Fri Jun 02 2006 - 15:30:23 CDT

Original text of this message

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