Performance issues in E-Business suit R12.1.3 , Recently upgraded from E-Biz 11.5.10

Hi All,

Facing Performance issues in E-Business suit R12.1.3 , Recently upgraded from E-Biz 11.5.10.

( E-biz 11.5.10 uses Oracle Data Base 10g & E-biz 12.1.3 uses Oracle data base 11.2.02 )

Custom SQL queries were working fine in E-biz 11.5.10, infact perfectly.

But when these queries are run on ExaData insance takes huge time and cost.

5 min query in 11.5.10 take 2 hours in 12.1.3

Most affected area is GL & SLA.

I have few questions.

1) Are SQL Hint advisable in Exadata. ( Few people keep telling that Hint must not be used.)

    Then how to increase performance ?

2) Why Oralce 11.2.0.2 on exadata is slower then Oracle 10g data base.

Thanks in advance.

Prashant Singh.