A instance of SQL Server Express 2016 that I'm in charge of has suddenly started to use a lot more CPU that usual. It's the backend database for a website, but doesn't see all that many queries due to aggressive caching in the webapp.
Normal CPU usage would be 0-2%, but it's now averaging around 25% (on a VM with 4 logical cores).
Perfmon shows avg batches/s as 2, but compilations/s is a constant 300.
All access to the database is through stored procedures, which mostly involve a single SELECT statement.
How can I find out what it's continually compiling?