RE: Same query with different response time

Are any indexes used in your plans and if so, did the cluster factors change?  

IF you have block visits minimized via an index prior to TSE but after TSE it has to skip around a lot more, that *could* explain changes in CPU and IO with no change in plan.  

Just a thing to check, probably not it but worth a glance.  

mwf  

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Lok P Sent: Sunday, June 27, 2021 10:19 PM
To: Pap
Cc: Oracle L
Subject: Re: Same query with different response time  

No other change happened. It was only tablespace encryption which has been done on top of existing data.  

I am also struggling to understand why the increase in IO is noted in SQL monitor.  

Regards

Lok

On Sun, 27 Jun 2021, 8:22 am Pap, <oracle.developer35_at_gmail.com> wrote:

I would expect a little more CPU requirement for any encryption/decryption activity. But in your SQL monitor it's also showing difference in IO. Not sure if it can only attributed to tablespace encryption. Any other change happened?      

On Sat, 26 Jun 2021, 7:49 pm Lok P, <loknath.73_at_gmail.com> wrote:

Hello Listers, We have seen TSE (tablespace encryption) implementation in the past in multiple databases but have not verified any performance aspect of this and we have also not got any complaint and now this has been mandated by the security team to do it for all the databases. However, we recently migrated one of the database to TSE i.e. tablespace encryption(Not column level TDE) and it's the lower environment/dev database, and dev team sent us few sql monitors noting performance degradation post TSE (some were ~100% slower which we were not expecting).

Attached are a few of the sql monitors which we got , stating the execution plan is same and volume is same , yet there is significant increase in response time. So I am not sure if we can validate from the sql monitor report, if the increase in execution time is only because of tablespace encryption or anything else. So can you please guide me here, how i can validate from this attached sql monitor if the degraded response time is because of TSE/tablespace encryption or anything else and how we can fix this issue?  

It's version 19.9.0.0.0 of Oracle.   

Regards

Lok

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