Log Forwarder is not able to gather all data when a VSAM ESDS data set is deleted or redefined

Symptom

A VSAM ESDS data set was deleted and then redefined. As a result, not all records written to the new data set were collected by the Log Forwarder.

Cause

When collecting data from a VSAM ESDS data set, the Log Forwarder periodically reads new records beginning with the last file position that was processed in the preceding record collection. If the VSAM ESDS data set is deleted, redefined and written with new records within a short time frame, the Log Forwarder cannot detect this is a newly defined data set. If the last file position in the old data set is still valid in the new data set, the records between the beginning of the new file and that file position will be skipped.

If you delete a VSAM dataset, you must wait for at least 60 seconds (1 minute) before redefining and inserting any data into this redefined dataset, so that the Log Forwarder can detect that the dataset has been deleted and redefined. Otherwise, the Log Forwarder is not able to gather all data that is inserted in the redefined VSAM dataset.

Solution

If you want to delete and redefine a VSAM ESDS data set whose data is gathered by the Log Forwarder, after deleting the old data set, wait at least 60 seconds (1 minute) before redefining and writing data to the new data set. The Log Forwarder can then detect this is a new data set and gather records from the beginning.