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基于Service Broker的异步消息传递

时间:2014-11-30  来源:互联网  作者:佚名

这里演示同一个SQL Server中不同数据库之间的基于Service Broker的异步消息传递,其中Stored Procedure充当Service Program。HelloWorldDB为目标数据库,DotNetFun2则为消息发送发的数据库。

同时,假设Server Broker的基本对象类型已经创建,如MessageType(XMLMessage), Contract(XMLContract), Queue(SendingQueue and ReceivingQueue)等等,具体操作可以参考《A simple tutorial on SQL Server 2005 Beta 2 Service Broker》。另外,因为在不同的Databases之间进行消息传递,因此需要创建Route,具体操作可以参考《SQL Server 2005 Beta 2 Service Broker: Create Route》。

1.创建Stored Procedure作为Internal Service Program.

USE HelloWorldDB

GO

Alter Procedure HelloWorldResponder

As

Begin

Declare @conversationHandle UNIQUEIDENTIFIER

Declare @message_body nvarchar(MAX)

Declare @message_type_name SYSNAME

WHILE (1=1)

BEGIN

BEGIN TRANSACTION

-- Wait for 1 seconds for messages to arrive

WAITFOR (

-- For simplicity we process one message at a time

RECEIVE TOP(1)

@message_type_name=message_type_name,

@conversationHandle=conversation_handle,

@message_body=message_body

FROM [ReceivingQueue]), TIMEOUT 1000

-- If a message was received, process it, else skip

IF (@@rowcount <= 0)

BREAK;

-- If this is a XML message,

-- respond with an appropriate greeting

IF @message_type_name = 'XMLMessage'

BEGIN

SEND ON CONVERSATION @conversationHandle

MESSAGE TYPE XMLMessage

('Hello From Rickie')

END CONVERSATION @conversationHandle

END

COMMIT

END

COMMIT

END

GO

该Stored Procedure负责从ReceivingQueue中检索消息,并根据Queue的Retention设置,来确定从Queue中移除消息或更新Queue中消息的状态。

2.设置目标队列(Target Queue)的激活机制

Use HelloWorldDB

go

ALTER QUEUE [ReceivingQueue] WITH

ACTIVATION (

STATUS = ON, -- Turn on internal activation

PROCEDURE_NAME = [HelloWorldResponder], -- Our stored proc

MAX_QUEUE_READERS = 4, -- Up to 4 concurrent readers

EXECUTE AS SELF) -- Execute as user of incoming dialog

设置上述创建的Stored Procedure,该Stored Procedure将被激活并处理Queue中的消息。

3.在Initiator端发送消息

Use DotNetFun2

go

DECLARE @conversationHandle uniqueidentifier

BEGIN TRANSACTION

-- Begin a dialog to the Hello World Service

BEGIN DIALOG @conversationHandle

FROM SERVICE [SendingService]

TO SERVICE 'ReceivingService','a727462b-52e7-4405-9eee-d19923729790'

ON CONTRACT [XMLContract]

WITH ENCRYPTION = OFF, LIFETIME = 600;

-- Send message

SEND ON CONVERSATION @conversationHandle

MESSAGE TYPE [XMLMessage]

('Welcome to Rickie Lee''s blog, www.cnblogs.com/rickie');

Select * From sys.conversation_endpoints

COMMIT

其中,TO SERVICE 'ReceivingService','a727462b-52e7-4405-9eee-d19923729790',’ReceivingSerice’表示目标Service名称,'a727462b-52e7-4405-9eee-d19923729790'则指定目标Service所在的数据库,可以通过如下SQL Script获取:

-- Retrieve remote broker instance guid

SELECT service_broker_guid

FROM sys.databases

WHERE database_id = DB_ID('HelloWorldDB')

另外,可以通过如下的SQL script来检测Initiator端收到的Reply消息:

Select cast(message_body as XML) From SendingQueue

Receive message_type_name,

cast(message_body as XML)

From SendingQueue

4.查询对话端点状态(State of Conversation Endpoints)

最后,可以通过在Target/Initiator端查询sys.conversation_endpoints表,获取Dialog对话状态:

Select * From sys.conversation_endpoints

(t114)

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