Configuration layer
Queue delays / performance issues
Queue delays without errors could indicate transaction locking. In that case, slow system performance could hold the queue in a sequence to update SAP ECC causing such delays. However, when system performance is high, you may not notice any delays.
Check the qRFC Administration for resource allocation. It is possible that the assigned resources (work processes) are not sufficient, which can lead to performance issues in other areas like PPF printing.
In case of such queue delays, also analyse whether the system is accessing the table ARFCRSTATE repeatedly. If yes, you can activate QRFC trace and analyse the response time during debugging.
Post goods issue (PGI) performance issues
Activate the ABAP trace to determine whether this table /lime/nquan & /LIME/NTREE consumes most of the memory/time. Send the trace results for both the slow performance and the best performance for comparison purposes.
If the issue appears again, you can find information on what to do next in the SAP Note 2594894