RAISERROR WITH NOWAIT

SQL Server buffers the output, so an error message or a result set may not appear directly at the client. In many cases, this is not an issue, but if you are running a long-running procedure, you may want to produce diagnostic messages. To have them displayed immediately in the client, you can use the WITH NOWAIT clause to the RAISERROR statement, as in this example:
PRINT 'This message does not display immediately'
WAITFOR DELAY '00:00:05'
RAISERROR ('But this one does', 0, 1) WITH NOWAIT
WAITFOR DELAY '00:00:05'
PRINT 'It''s over now'
Once there is a message with NOWAIT, all that is ahead of the message in the buffer is also passed to the client.
Unfortunately, there is a bug in SQL Server with NOWAIT, which affects you only if you are calling a procedure through RPC (remote procedure call), so that it this case, SQL Server buffers the messages nevertheless. RPC is the normal way to call a procedure from an application (at least it should be), but if you are running a script from OSQL or Query Analyzer, this bug does not affect you

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