Re: Inconsistent SQL tuning results
- From: Cary Millsap <cary.millsap@xxxxxxxxxxxx>
- To: michaeljmoore@xxxxxxxxx
- Date: Mon, 7 Feb 2011 14:37:46 -0600
Mike,
I feel your pain. See
http://carymillsap.blogspot.com/2010/08/mister-trace.html.
Cary Millsap
Method R Corporation
http://method-r.com
http://carymillsap.blogspot.com
On Mon, Feb 7, 2011 at 12:07 PM, Michael Moore <michaeljmoore@xxxxxxxxx>wrote:
> Thanks guys.
> I will run trace, even if it does take an act of congress and a letter from
> my doctor to get the dbas to give my the necessary privs.
>
> I'll let you know how it went.
> Thanks again,
> Mike
>
>
> On Mon, Feb 7, 2011 at 9:59 AM, Daniel W. Fink <daniel.fink@xxxxxxxxxxxxxx
> > wrote:
>
>> Without additional information, the only option available is "Guess".
>>
>> Run extended sql trace (dbms_monitor.session_trace_enable, event 10046,
>> etc), run the trace file(s) through tkprof and analyze the differences.
>>
>>
>>
>> On 2/7/2011 10:49 AM, Michael Moore wrote:
>>
>> I've been trying to tune a SQL statement but I get very inconsistent
>> results.
>>
>> I always start with:
>> alter system flush shared_pool;
>> alter system flush buffer_cache;
>>
>> Then I run the SQL, but the first time I run it, it can take as much as
>> 7 minutes. On the 2nd, 3rd, and 4th runs, it takes
>> 40 sec, 49 sec, 35 sec respectively.
>>
>> So my question is: What might account for the huge difference in run
>> time between the first run and successive runs?
>>
>> Thanks,
>> Mike
>>
>>
>>
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>>
>>
>
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