use tempdb


CHECKPOINT;
GO
DBCC DROPCLEANBUFFERS;
GO


DBCC FREEPROCCACHE;
GO


DBCC FREESYSTEMCACHE ('ALL');
GO


DBCC FREESESSIONCACHE;
GO


DBCC SHRINKFILE (TEMPDEV2, 1024);   --- New file size in MB
GO



https://sqlsunday.com/2013/08/11/shrinking-tempdb-without-restarting-sql-server/