We have observed duplicate entries for the same IP address or hostname within the blacklist tables, specifically in CM_BLACKLIST_COMPUTER_SYSTEM and CM_BLACKLIST_DEVICE.
Why does this happen?
DX UIM 23.4.*
Working as designed
Devices with the same Hostname and IP address can be present in the CM_BLACKLIST_COMPUTER_SYSTEM table for the same reason they appear in CM_COMPUTER_SYSTEM .
Devices (Master devices with a single cs_id) can exist in the DX UIM DB with the same hostname and coinciding IP Address in the scenario where any discovery_server un-match property exist in the device's attributes. A common and basic example of this scenario would be a system discovered twice from 2 distinct hubs with 2 different ORIGINS.
When 2 devices are correctly not correlated in the inventory, they will also be treated as different devices (different cs_id and related dev_id's) in the Blacklist tables.