Question

我一直在使用此sp_getapplock锁定资源的会话。以下是过程：

CREATE Procedure [dbo].[system-LockProcedure] @procname varchar(200)

AS 

--BEGIN TRAN
BEGIN

DECLARE @lockreturn int,
        @lockresource varchar(200)               --sysname


SELECT @lockresource =    @procname    



              -- The below line will try to acquire an exclusive lock on the PROC for the session, If the Proc is already in execution the @lockreturn value will be > 0

                 EXEC @lockreturn = sp_getapplock @lockresource, @LockMode = 'Exclusive', @LockOwner = 'Session'  , @LockTimeout = 100
                                                                Print @lockreturn 

                 IF @lockreturn <> 0
                 BEGIN

                        RAISERROR ('Another instance of the procedure is already running', 16, 1)
                                                                                                RETURN
                 END

                -- The Code to be executed goes here. All the core logic of the proc goes here..

              Print 'Procedure Execution Started for user: ' +  cast (CURRENT_USER as nvarchar(20))+ ' for session: ' + cast (@@SPID as nvarchar(10))

                -- This is just to make the system wait for 30 seconds and make sure if there is any concurrent execution triggered will fail

                                                                exec @lockresource

              Print 'Procedure Execution Ended for user: ' +  cast (CURRENT_USER as nvarchar(20))+ ' for session: ' + cast (@@SPID as nvarchar(10))

                                                  Print @lockreturn

                -- This is to release the lock once the SP code is ran completely

                                                EXEC sp_releaseapplock @lockresource , 'Session'

                                                 -- END TRY


    END

我们也可以在您本地执行此过程以进行测试。

当我在一个会话中执行该过程时，如果有人想要执行此存储过程，则它将显示一条消息，表明它已在其他会话中打开。使用资源名称（也是对象

）执行此过程时

EXEC dbo.[system-LockProcedure]'dbo.usp_Test1'

一切正常

EXEC dbo.[system-LockProcedure]'dbo.usp_Test2'

具有输入参数，并要求输入参数

Error  : 
Msg 201, Level 16, State 4, Procedure USP_Test2, Line 23
Procedure or function 'USP_Test2' expects parameter '@ThreadID', which was not supplied.

当StoreProcedure没有输入参数时，sp_getapplock起作用

0 个答案: