SQL Server Service Broker-消息超时

Question

我正在研究sql服务器服务代理作为我们应用程序的消息处理技术。

在我们的方案中，从一个客户端应用程序（WPF）发送的消息需要在服务代理中排队，其他客户端应用程序（android）会接收它们。消息是时间敏感的，接收者需要在消息被发送到队列后的“ X”分钟（例如2分钟）之内接收，如果到那时仍无法接收，则消息必须过期并从接收者中删除。队列。

有没有办法告诉服务代理在“ x”分钟后使消息超时？

编辑：添加了我用来测试此脚本。

CREATE DATABASE ServiceBrokerTest
GO

ALTER DATABASE ServiceBrokerTest SET ENABLE_BROKER WITH ROLLBACK IMMEDIATE 
GO

/****** Object:  MessageType [SampleMsgType] ***/
CREATE MESSAGE TYPE [SampleMsgType] AUTHORIZATION [dbo] VALIDATION = NONE
GO

/****** Object:  ServiceContract [MsgContract]    ******/
CREATE CONTRACT [MsgContract] AUTHORIZATION [dbo] ([SampleMsgType] SENT BY INITIATOR)
GO

/****** Object:  ServiceQueue [dbo].[Queue1]    ******/
CREATE QUEUE [dbo].[Queue1] WITH STATUS = ON , RETENTION = OFF , POISON_MESSAGE_HANDLING (STATUS = ON)  ON [PRIMARY] 
GO

/****** Object:  BrokerService [MsgService]    ******/
CREATE SERVICE [MsgService]  AUTHORIZATION [dbo]  ON QUEUE [dbo].[Queue1] ([MsgContract])
GO

/****** Object:  StoredProcedure [dbo].[SendMsg]  ******/
CREATE PROC [dbo].[SendMsg]
@msg NVARCHAR(MAX)
AS

BEGIN
    SET NOCOUNT ON
    DECLARE @handle UNIQUEIDENTIFIER

    BEGIN TRANSACTION
        BEGIN dialog @handle 
            FROM SERVICE [MsgService]
            TO SERVICE 'MsgService'
            ON CONTRACT [MsgContract]
            WITH ENCRYPTION = OFF, LIFETIME = 20

        ;SEND ON CONVERSATION @handle
            MESSAGE TYPE [SampleMsgType] (@msg)
        END CONVERSATION @handle
    COMMIT TRANSACTION
END

/****** Object:  StoredProcedure [dbo].[ReceiveMsg] ******/
CREATE PROC [dbo].[ReceiveMsg]
@msg NVARCHAR(MAX) OUT

AS

BEGIN
    SET NOCOUNT ON
    DECLARE @handle UNIQUEIDENTIFIER

    DECLARE @msgTable TABLE (
        handle UNIQUEIDENTIFIER,
        msg NVARCHAR(MAX),
        msgType VARCHAR(300));

    SET @handle = NULL

    WAITFOR (
        RECEIVE [conversation_handle], message_body, message_type_name
        FROM [dbo].[Queue1]
        INTO @msgTable
        ), TIMEOUT 25000

        SELECT @handle = handle
        FROM @msgTable
        WHERE msgType = 'http://schemas.microsoft.com/SQL/ServiceBroker/EndDialog'

        IF @handle is not null
            BEGIN 
                END CONVERSATION @handle
            END

        SELECT @msg = msg
        FROM @msgTable
        WHERE msgType = 'SampleMsgType'
END 

GO

Answer 1

对话框生存期可以在以下BEGIN DIALOG语句中指定：

BEGIN DIALOG @handle
FROM SERVICE [...]
TO SERVICE '...'
ON CONTRACT [...]
, LIFETIME = <dialog lifetime>;

对话框必须在其生存期内完成（双方结束），否则将出错。因此，您可以启动一个具有2分钟生命周期的对话框，并在其上发送一个或多个消息。目标必须在这2分钟内接收并处理该消息，否则对话框将出错。

您还可以使用对话优先级，并在优先级较高的通道上发送对时间敏感的消息。这将确保Service Broker传输将优先级分配给您的敏感消息，并且客户端应用程序RECEIVE语句会“冒泡”优先级较高的时间敏感消息，并首先接收它们。