Is there any bug in 12.1 that is causing SQL to behave badly as the reason been
looking to create profile/baseline to fix the execution plan. Currently,one of
the SQL is changing execution plan several time. I can see now 4 plan and so
tuning is not working when new plan comes up and break the performance. This is
On Wednesday, December 6, 2017 6:29 PM, dba Wilson
Agree with Stefan. You need to find out the root cause.
Recommend a tool for you, which is being used by me recently :). SQLBooster.
You can find the download url and the Power Point I prepared for my dev team.
2017-12-05 19:56 GMT+11:00 Stefan Koehler <contact@xxxxxxxx>:
the problem is not the SQL Profile (they can be very useful) but the Oracle
Tuning Advisor. It seems like you just accepted the recommendation by Oracle
Tuning Advisor without understanding the root cause.
The SQL Profile by Oracle Tuning Advisor does not fix an execution plan - so it
is not very uncommon to have different costs in different environments if they
are not EXACTLY the same. The SQL Profile by Oracle Tuning Advisor only
provides some scale factors (in your case for joins) but the optimizer is still
free to choose from various transformations, access paths and join methods.
So my recommendation: Delete the SQL profile, understand the root cause and fix
this problem :-)
Independent Oracle performance consultant and researcher
Sanjay Mishra <dmarc-noreply@xxxxxxxxxxxxx> hat am 4. Dezember 2017 um 21:48--
Is it common that if I transfer any SQL profile created in the lower
environment and working fine to be moved to prod but found it is not
achieving the same response? Running the same Exact SQL in both environments
and both Dev and Test are newly refreshed with Prod data. The environment is
12c (188.8.131.52) and SQL profile is enabled. The only difference is that Lower
environment COSt in explanation where the query is running 5 times faster is
more that based Execution plan COST in a production environment.
Dev Env: Before Oracle Tuning Advisor accepted SQL Profile the query cost was
9500K and taking 30Min. After accepting Profile it is reduced to 10Min
Test Env: Execution Plan Cose comes 235K and taking 1hr 40 min. It shows
that it has used SQL profile also. The same time was even taken without using
I agree with lots of experts comments that SQL profile is not the best way. I
tried to use Opt_estimate but not able to understand as to how to interpret
it. It comes as
opt_estimate(@"SEL$1", JOIN, ("Sol_c_tbl"@"$SEL$1", "Sol_c_tbk"@$SEL$1",
opt_estimate(@"SEL$1", JOIN, ("Sol_c_tbk"@"$SEL$1"), SCALE_ROWS=0.212222124)
opt_estimate(@"SEL$1", JOIN, ("Sol_c_tbk"@$SEL$1", "Sol_c_tba"$SEL$1"),
I got the above from one of the Frank blogs from dbi Services
Any clues as instead of SQL profile I can check more based on above profile
hints to directly tune the environment.