SQL Server: User Settable Object

SQL Server: User Settable Object

The User Settable object in Microsoft® SQL Server™ allows you to create custom counter instances. Use custom counter instances to monitor aspects of the server not monitored by existing counters, such as components unique to your SQL Server database (for example, the number of customer orders logged or the product inventory).

The SQL Server User Settable object contains 10 instances of the query counter: User counter 1 through User counter 10. These counters map to the SQL Server stored procedures sp_user_counter1 through sp_user_counter10. As these stored procedures are executed by user applications, the values set by the stored procedures are displayed in System Monitor (Performance Monitor in Microsoft Windows NT® 4.0). A counter can monitor any single integer value (for example, a stored procedure that counts how many orders for a particular product have occurred in one day).

Note  The user counter stored procedures are not polled automatically by System Monitor. They must be explicitly executed by a user application for the counter values to be updated. Use a trigger to automatically update the value of the counter. For example, to create a counter that monitors the number of rows in a table, create an INSERT and DELETE trigger on the table that executes:

SELECT COUNT(*) FROM table

Whenever the trigger is fired because of an INSERT or DELETE operation occurring on the table, the System Monitor counter is automatically updated.

This is the SQL Server User Settable counter.

To make use of the user counter stored procedures, execute them from your own application with a single integer parameter representing the new value for the counter. For example, to set User counter 1 to the value 10, execute this Transact-SQL statement:

EXECUTE sp_user_counter1 10

The user counter stored procedures can be called from anywhere other stored procedures can be called, such as your own stored procedures. For example, you can create the following stored procedure to count the number of connections and attempted connections made since an instance of SQL Server was started:

DROP PROC My_Proc
GO
CREATE PROC My_Proc
AS 
   EXECUTE sp_user_counter1 @@CONNECTIONS
GO

The @@CONNECTIONS function returns the number of connections or attempted connections since an instance of SQL Server was started. This value is passed to the sp_user_counter1 stored procedure as the parameter.

Important  Make the queries defined in the user counter stored procedures as simple as possible. Memory-intensive queries that perform substantial sort or hash operations or queries that perform large amounts of I/O are expensive to execute and can impact performance.