Common Misconceptions In Sql Server

A TRUNCATE TABLE operation is non-logged.(FALSE)

There is no such thing as a non-logged operation in a user database. The only non-logged operations that SQL Server performs are those on the version store in tempdb.

A TRUNCATE TABLE operation does a wholesale delete of all data in the table. The individual records are not deleted one-by-one, instead the data pages comprising the table are simply deallocated. The allocations are unhooked from the table and put onto a queue to be deallocated by a background task called the deferred-drop task. The deferred-drop task does the deallocations instead of them being done as part of the regular transaction so that no locks need to be acquired while deallocating entire extents.

Paul S. Randal