RE: VLDBA's: gather stats on a large table

From: Martic Zoran <zoran_martic_at_yahoo.com>
Date: Tue, 12 Apr 2005 02:04:19 -0700 (PDT)
Message-ID: <20050412090420.12156.qmail@web52601.mail.yahoo.com>

Hi Christian,

My understanding is a little bit contradictory with your last sentence because whenever Oracle at parse time does not know exactly the one partition it will operate on (e.g. when you have from KEY to KEY or you have from 1 to 10) Oracle optimizer will use global statistics.

Only if you have fixed one partition used in the execution plan Oracle is going to use partition statistics of that particular partition, like from 10 to 10.

My understanding can have the flaw because I used asktom site (usually trustful) and did not try it myself (lazy).

Would you let me know if my understanding is not true here, please?

Best regards,
Zoran

• Christian Antognini <Christian.Antognini_at_trivadis.com> wrote:
  > >As the app doesnt specify the partition in
  > selects,=20
  > >I need to maintain global stats, which means I need
  > >to rescan all 7bn rows each time.
  >
  > Does the application take advantage of partition
  > pruning? If yes, even =
  > if the SQL are not referencing the partitions
  > directly, it's important =
  > to have partition-level stats.
  

  ---

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Received on Tue Apr 12 2005 - 05:08:18 CDT