We have an overnight process to check space used on the databases in a server.
sp_spaceused reported it was blocked on executing line 404 which is
select @used_pages = lct_admin("num_logpages", db_id())
The process was blocked on a CHKPOINT WRKR. (We have 4 CHKPOINT WRKR processes running).
What would cause the sp_spaceused to be blocked in this way ?