In the Data Feed Manager , the "Target Record Processing" setting on the Run Configuration tab determines how Archer handles records that are not present in the current source file. As taught in Archer Administration II , selecting the Delete radio button (often referred to as a "destructive feed" or "mirroring") instructs Archer to compare the source file to the target application.

If the feed finds records in the target application that do not match the keys provided in the source file, it will delete them. In this scenario, since there are only 20 entries in the source file, Archer will keep (or create) those 20 records and delete the remaining 80 records that were already in the system but were missing from the source. Consequently, the final count in the target application will be 20. This setting is typically used for synchronization tasks where Archer must exactly match an external "system of record." Administrators are cautioned when using this setting, as it can lead to massive data loss if the source file is accidentally truncated or filtered incorrectly.