RE: VLDBA's: gather stats on a large table
- From: Martic Zoran <zoran_martic@xxxxxxxxx>
- To: Christian.Antognini@xxxxxxxxxxxx, mark.teehan@xxxxxxxx
- Date: Tue, 12 Apr 2005 02:04:19 -0700 (PDT)
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@xxxxxxxxxxxx> 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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