two things came to my mind.
1) CPU increase due to execution plan change
You can have execution plan changes as you had to move (e.g. with
dbms_redefinition) the data to encrypt it after enabling TDE and this can lead
to a CPU increase.
2) CPU type
Your current used CPU type does not support hardware cryptographic acceleration
or you are using TDE column encryption. For more details please check this
white paper on page 3:
P.S.: Despite all that there may be cases where TDE really has a performance
impact (had some nice discussion about that at Hotsos last year).
Independent Oracle performance consultant and researcher
Arun Chugh <arun.chugh1610@xxxxxxxxx> hat am 7. Juni 2018 um 05:51--
We have encrypted almost all the datafiles of the database, post that the
performance of the database degraded to almost 40-50%
Could anyone suggest what is the other alternative method that we can use in
order to secure data with bit performance impact.