Payroll is getting hung ... HCM 9.1

Hi,

We have upgraded HRMS 8.8 SP1 to HCM 9.1 FP1.

Platform : Redhat Linux 5 64 bit

Database : upgraded from 9.2.0.6 to 11.2.0.1

Issue : Payroll process is not consistent.

1)    Payroll is running in small chunk

2)    In bigger chunk sometimes its running sometimes not.

3)    Most of the time when its not running, I have seen 4 tables are going under transactional (exclusive row lock) & not getting released. Subsequent payroll is also getting hung. Unless I will restart the database, it will not work

4)    We have run the payroll for full population on SIT, it went fine. Parameter wise there is no difference between SIT & UAT

If I check select * from dba_dml_locks; --- no locks found