Embodiments of the invention are directed to determining a universal device identifier (UDID) for a client device, based on multiple service-dependent identifiers (SDIDs) used by client applications, websites, or other services to identify the client device. SDID types are prioritized with pre-assigned weights. A received SDID causes a single database read to access all other SDIDs, and any existing UDID(s) associated with the client device. A final UDID is created or selected based on the SDID weights. The database is updated in a sequence that enables self recovery of a prior UDID in case of database error during update. First, any non-selected UDID records are updated with the final UDID. Next, lower weighted SDID records are updated. The final UDID record is updated. The highest weighted SDID record is updated last, to preserve the prior UDID as long as possible in case of update error, which aborts the remaining update.