SPID Change for a process? On SQL Server 2012 can a process SPID change mid-operation? We have a very unique query that we've been monitoring (production, but controlled testing) and have seen it at different intervals with different SPIDs. It's a unique query that no one else should be running, at least with these parameters, and as such we shouldn't see it with a different SPID, unless... can a query can change SPIDs mid process?

My understanding is this is impossible, so more likely is that for some unknown reason the application is re-submitting this unique and performance destroying query, thus generating a new SPID, despite no user interaction.
No, the SPID (Server Process ID) is assigned the moment an application establishes a connection/session to the database and is retained until the connection/session ends.