Process Block Itself

Hi to everybody,

i have this problem.

sometimes a process in my SQL Server 2005 (upd 2) is blocked from itself. If I find in monitor it wait for a lock_M_Sch_M on a temporary table as you can see from

select * from sys.dm_tran_locks where request_session_id=51 and request_status <> 'GRANT'



resorce type : OBJECT

resource id : 218899226

request mode : Sch-M

request status WAIT

request_session id : 51

request life time : 33554432



or from

SELECT * FROM sys.dm_os_waiting_tasks WHERE SESSION_ID=51



waiting task address : 0x0000000000C2F198

session id : 51

wait type : LCK_M_SCH_M

resource address : 0x0000000201C71300

blocking task address : 0x0000000000C2F198

blocking session id = 51

resource description objectlock lockPartition=0 objid=218899226 subresource=FULL dbid=2 id=lock80d04900 mode=Sch-S associatedObjectId=218899226



I resolve this problem only with restart of sql server . that clear tempdb and eliminate this process



I think is not a problem about latch present from sql server 2000 sp4 (I read some document abount this problem)



So I haven't idea how to resolve this problem and how to kill this kind of process without to restart sql server



thanks in advance



Luca