1. An electronic mail processing system comprising: at least one processor; at least one computer-readable medium in communication with the at least one processor; and at least one electronic mail processing module: residing on the medium, and comprising instructions, that upon execution by the at least one processor to are operative to: store, in a database assigned to a first direct access proxy, a list of electronic mail message unique identifiers (UIDs) identifying a plurality of messages, the messages associated with a device, the device assigned to the first direct access proxy; store the list in a cache, receive, in the direct access proxy, a query directed to UIDs of the device; determine that the database is unavailable due to database downtime; determine that the device has not been assigned to a subsequent direct access proxy; and respond to the query using the cache.