Re: cardinality feedback in 19c

Jonathan

They are all after newly added and conventionally loaded partitions on which statistics for conventional DML is used. The application is then re-running fresh statistics on the newly added partition every 2 hours. Now those queries are back to their good plan. But I would like to avoid such a case of execution plan switch. The first optimized execution plan (the one on which Oracle realizes that it has a cardinality misestimates and marked the underlying cursor for a new re-optimization) was a very good one J

So, now thinking whether canceling statistics feedback on those queries will help to avoid this plan switch

Best regards

Mohamed

Le mar. 27 avr. 2021 à 15:04, Jonathan Lewis <jlewisoracle_at_gmail.com> a écrit :

> Mohamed,
>
> Have you spotted any common pattern to the 6 unlucky queries?
>
> Regards
> Jonathan Lewis
>
>
> On Tue, 27 Apr 2021 at 13:53, Mohamed Houri <mohamed.houri_at_gmail.com>
> wrote:
>
>> Hello Sayan
>>
>> Thanks for your answer. It confirms why I haven't experienced any
>> performs pain with cardinality feedback in all the 19c databases I have to
>> deal with. Until today where 6 critical queries changed their execution
>> plan from a good one to a very bad one and the non-sharing reason was
>> USE_FEEDBACK_STATS
>>
>> Best regards
>> Mohamed
>>
>>

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