Query slows down after upgrade

Question

Hi,
After upgrade from oracle 10 to oracle 11 a simple query is slowing down alot.
Same amount of records, same table only the execution cost time is increased
Can someone give me some feedback over this problem?
Can I check some things to look into the problem?
Thx in advance.
Greetings
query:
Select nvl(sum(a.BM_OPENSTAAND_DEBET- a.BM_OPENSTAAND_CREDIT),0)
from bh.bh123gh a
where
a.F123_AR_NR>='4400000000' and
a.F123_AR_NR<='4404000000' and
a.F123_KL_LEV_AR_NR='0631001000' and
a.SRT_REK=2 and
a.F123_BKJR>=0000 and
a.F123_BKJR<=2011 and
a.F123_FIRMA=2
explain plans
oracle 11
cost 1,792
Bytes: 38
Cardinality: 1
oracle 10
cost 1,594
Bytes: 38
Cardinality: 1

Answer 1

>
After upgrade from oracle 10 to oracle 11 a simple query is slowing down alot.
Same amount of records, same table only the execution cost time is increased
Can someone give me some feedback over this problem?
Can I check some things to look into the problem?
Thx in advance.
>
Is it just one query or all queries are behaving strangely? If it's just one query, do a trace and see where it's slowing down.
In the meanwhile, you can also modify the optimizer_features_enable parameter at session level and check the explain plan.
Alter session set optimizer_features_enable='10.2.0.5';
Now test the query.
By the way, if you are just worried about the COST factor, you can just ignore it. COST by itself has no real meaning. You will only have to look at the response time.
Regards