For the optimization of ZFI_GRIR to improve its performance, we would like to suggest to create a copy program of ZFI_GRIR (ZFI_GRIR2) where we will do our initial change then to be moved to Production for testing. This is because we cannot test the issue on the program performance and its corresponding fix in DEV or in QAS since the data in these clients are not as huge as PROD.
If you're okay with the suggestion, we'll move the copy program (ZFI_GRIR2) in PROD and we'll request for FF ID to debug it as well.