Our system processes around 1500-2000 requests for "PO Output For Communication" daily.
Normally this request completes in ~3 minutes. But sometimes, when there are more than 50-60 requests for this program submitted, program execution time shoots up from 3-4 minutes to 40-50 Minutes.
We implemented suggestion as per below note. However, didnt observe significant improvement during peak times.
PO Output For Communication Performance Issues But SQL Trace Show No Performance Problems(Doc ID 1575175.1)
Assuming you have an AWR license, what does the AWR report show for that hour ?
MOS Doc 1540650.1
MOS Doc 1672174.1
Can you enable trace on the program, and try to see the query.
Also as suggested by Srini, check the top queries in AWR report.