##OPTIONS bit mask versus DISABLE_DEF_CNST_CHK - sql-server

Question

We're trying to diagnose some performance issues on both SQL Server 2008 and SQL Server 2008 R2 arising from bad query plans that get cached on behalf of users but are unable to exactly reproduce them in SSMS as we cannot convince SQL Server to match the application's set_options value of 255 that gets returned from sys.dm_exec_plan_attributes, aka. ##OPTIONS.
The ##OPTIONS bit mask is documented at the following MSDN page:
Configure the user options Server Configuration Option
According to the above page the following combination of SET statements should yield an ##OPTIONS value of 255:
SET DISABLE_DEF_CNST_CHK ON
SET IMPLICIT_TRANSACTIONS ON
SET CURSOR_CLOSE_ON_COMMIT ON
SET ANSI_WARNINGS ON
SET ANSI_PADDING ON
SET ANSI_NULLS ON
SET ARITHABORT ON
SET ARITHIGNORE ON
SET QUOTED_IDENTIFIER OFF
SET NOCOUNT OFF
SET ANSI_NULL_DFLT_ON OFF
SET ANSI_NULL_DFLT_OFF OFF
SET CONCAT_NULL_YIELDS_NULL OFF
SET NUMERIC_ROUNDABORT OFF
SET XACT_ABORT OFF
But when you exec that you get the warning:
Line 1: The option 'DISABLE_DEF_CNST_CHK' is obsolete and has no effect.
And PRINT ##OPTIONS returns 254 instead of 255.
Clearly Connection Pooling is able to sort this out when you see EXEC sp_reset_connection in SQL Profiler, as none of our application code actually changes any SET options. But of course we can't call sp_reset_connection from SSMS:
Msg 208, Level 16, State 9, Procedure sp_reset_connection, Line 1
Invalid object name 'sp_reset_connection'.
Is there a trick to get that last DISABLE_DEF_CNST_CHK bit into play? An alternative option name or a system table to tweak?

Answer 1

Well I've found one way to SET DISABLE_DEF_CNST_CHK ON but I DO NOT recommend doing this on a production server...
When new connections are established SQL Server sets ##OPTIONS to the value stored against the 'user options' row in the sys.configurations view. This value defaults to 0. You can check the configured and running value with:
select * from sys.configurations where name = 'user options'
-- or:
EXEC sp_configure 'user options'
As a user with the sysadmin or serveradmin role you can change the value for future connections with:
EXEC sp_configure 'user options', 1
GO
RECONFIGURE
GO
Note that changing this setting affects all future connections to the server which is why I DO NOT recommend doing this on a production server.
After changing this configuration value, then opening a new connection in SSMS, using the other SET options as described in the original question finally got us to ##OPTIONS 255.