AW: Dynamic sampling
- From: Petr Novak <Petr.Novak@xxxxxxxxxxxx>
- To: "hemantkchitale@xxxxxxxxx" <hemantkchitale@xxxxxxxxx>, "william@xxxxxxxxxxxxxxxxxxxx" <william@xxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 11 Nov 2010 10:25:38 +0000
You can check which accessed tables and their indexes miss statistics or
search for statements with hint /* OPT_DYN_SAMP */ in v$SQL
Best Regards,
Petr
________________________________________
Von: oracle-l-bounce@xxxxxxxxxxxxx [oracle-l-bounce@xxxxxxxxxxxxx]" im
Auftrag von "Hemant K Chitale [hemantkchitale@xxxxxxxxx]
Gesendet: Donnerstag, 11. November 2010 11:12
Bis: william@xxxxxxxxxxxxxxxxxxxx
Cc: ORACLE-L
Betreff: Re: Dynamic sampling
I don't have access to run the query. It is called from a procedure in a
package executed by the application. I can only "see" it.
Hemant K Chitale
http://hemantoracledba.blogspot.com
sent from my smartphone
On Nov 11, 2010 4:39 PM, "William Robertson"
<william@xxxxxxxxxxxxxxxxxxxx<mailto:william@xxxxxxxxxxxxxxxxxxxx>> wrote:
Ah, agreed that would be a helpful feature. It would also be good if the plan
could indicate whether global or partition stats (or default estimates) were
used and whether they are stale.
I wouldn't be without dynamic sampling though. I find one instant-tuning
technique is to try the query at level 9 (either via hint or alter session) and
see if it produces a better plan, preferably using 'ADVANCED' in the call to
dbms_xplan.display_cursor to get the outline section. Then if it does, figure
out what's better about it. It's a bit like using DBMS_SQLTUNE but without the
requirement for special privileges.
William Robertson
-------- Original Message --------
Subject: Re: Dynamic sampling
From: Hemant K Chitale <hemantkch...
CC: ORACLE-L <oracle-l@xxxxxxxxxxxxx<mailto:oracle-l@xxxxxxxxxxxxx>>
Date: 11/11/2010 08:20
>
> The number of lines (operations) in...
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