In checking Log File Viewer for noteworthy events I came across a log that I wanted to investigate.
Let's say the log notes the Source as SPID1234
My question: Is this SPID tied to the actual connection that generated the log or is the SPID associated with the process that is writing this to the log?
In your scenario, the SPID1234, which means the session that is running this command has ID of 1234.
from here
A SPID in SQL Server is a Server Process ID. These process ID’s are essentially sessions in SQL Server. Everytime an application connects to SQL Server, a new connection (or SPID) is created. This connection has a defined scope and memory space and cannot interact with other SPIDs. The term SPID is synonymous with Connection, or Session.