I performed a load testing on our environment,where for eg. stored procedure say "sp" was called multiple times to process on different set of ids.
During load testing this store procedure encountered multiple blocking over single record situated in table say "A"
Out of all these blocking, first blocking was occurred while the proc was deleting some records from table A in one session and blocker script was trying to insert few records in table B in another session.
But table A and B does not have any relation between them (no foreign key over each other and no triggers) Although they have primary key which is a foreign key on some other common table. But I think that should not be the issue.
the mentioned blocking has wait type : LCK_M_U
I could not figure out the exact reason, which is causing the blocking.