Re: Really strange performance issue
- From: Andrew Kerber <andrew.kerber@xxxxxxxxx>
- To: Chris Taylor <christopherdtaylor1994@xxxxxxxxx>
- Date: Thu, 30 Oct 2014 10:15:16 -0500
Yes, that's why I changed the parameter at the session level. I am now in the
process of gathering traces of both runs to see what the difference is. It
still looks like some strange bug to me, feedback should improve performance,
at least in my world. I could use a baseline, but I am afraid of this
happening with other queries, so I want details on what is going on.
Sent from my iPad
> On Oct 30, 2014, at 10:07 AM, Chris Taylor <christopherdtaylor1994@xxxxxxxxx>
> wrote:
>
> Wouldn't it be better to attack the problem instead of changing the whole
> "world" by setting the db parameter?
>
> If it's one SQL statement, I'd use a SQL Profile to guarantee the plan that I
> want is used before forcing something at the db level.
>
> Chris
>
>> On Thu, Oct 30, 2014 at 10:03 AM, Andrew Kerber <andrew.kerber@xxxxxxxxx>
>> wrote:
>> And we have a winner. The actual plan must have changed, even though when I
>> just ran the explain command it did not. I turned off
>> _optimizer_use_feedback and that fixes it. The question is why?
>>
>> Sent from my iPad
>>
>>> On Oct 30, 2014, at 9:49 AM, Mauro Pagano <mauro.pagano@xxxxxxxxx> wrote:
>>>
>>> Does the execution plan change between first and second execution?
>>> If no the ignore the rest of my message but if yes then an educated guess
>>> (since we have no other info available) would be "cardinality feedback",
>>> you can test it setting "optimizer_use_feedback" = false
>>>
>>>> On Thu, Oct 30, 2014 at 10:42 AM, Howard Latham <howard.latham@xxxxxxxxx>
>>>> wrote:
>>>> Any chance of seeing the Query please?
>>>> --
>>>> //www.freelists.org/webpage/oracle-l
>>>
>>>
>>>
>>> --
>>> http://about.me/mauro.pagano
>
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