All, New DBA trying to get a handle on performance. I was going over the stored procedure/sql batch performance by ApplicationName (collected via SQL Profiler) and found that one of the worse performers of one of our applications was a call to a stored proc. The confusing thing is that this sproc requires an argument @source and the poor performing calls to this stored proc appears in the trace information (TextData) as just the simply stored proc with no arguments. I can see calls to this sproc with arguments in the same trace - which are good performers. Data summarized via excel: SP Call Execs Avg CPUAvg ReadExec*CPU sp_XXX_in 428 67458123288758 sp_XX_in 'BankX' 34 257 75 I can't explain how this happens - as I would expect that SQL Server would throw an errror if you called the stored proc with no arguments. Then I thought perhaps it is a case where the stored proc is called with an un-initialize parameter like so declare @source char(20) exec sp_XXX_in @source or declare @source char(20) set @sounce=null exec sp_XXX_in @source Can't reproduce the bad behavior from within Query Analyzer. The thing about the calls is that they look like table scans on a large table (in terms of writes). I then thought that perhaps this is some symptom of using ado - something like a Parameters.Refresh making a call to the server. Antone ever see anything like this??? Joe E O Here is code like the stored proc: CREATE procedure sp_XXX_in @source char(20) AS SELECT top 200 transid, vendor_id, loan_num -- < Lots of columns snipped to brevity > FROM big_order_table with (nolock) WHERE (identity_column > 900000 and status = 'pending' AND appr_or_eval_flag = 'E' and source = @source) .