Problem Description:

Many a times when we are troubleshooting any performance issue and we see that there are multiple processes blocking to each other and in such cases it becomes difficult to identify which is the lead blocker causing blocking to the database.

Solution:

Below query can be used to identify lead blocker.

select distinct blocked from master..sysprocesses where blocked >0 and blocked not in (select spid from master..sysprocesses where blocked >0)