Detecting dirty reads from a stored procedure

Question

I\'ve got 100 threads that are each calling the stored procedure as defined below.

How do I prevent dirty reads?

SET QUOTED_IDENTIFIER OFF
SET ANSI_NULLS         


        

Answer 1

One option would be to use the sp_getapplock system stored procedure and use the built in locking of sql server to ensure serialized access to a resource.

CREATE PROC MyCriticalWork(@MyParam INT)      
AS
    DECLARE @LockRequestResult INT
    SET @LockRequestResult=0

    DECLARE @MyTimeoutMiliseconds INT
    SET @MyTimeoutMiliseconds=5000--Wait only five seconds max then timeouit

    BEGIN TRAN

    EXEC @LockRequestResult=SP_GETAPPLOCK 'MyCriticalWork','Exclusive','Transaction',@MyTimeoutMiliseconds
    IF(@LockRequestResult>=0)BEGIN

        /*
        DO YOUR CRITICAL READS AND WRITES HERE
        */

        --Release the lock
        COMMIT TRAN
    END ELSE
        ROLLBACK TRAN