queue elements. For example, I am using a queue to process requests to call
a web service. If the web service is unable to process a particular request,
I would like that request to be retried 5 minutes from now while continuing
to process other requests that may be in the queue. I suspect I may need
additional queues, such as a delay queue. Any ideas would be appreciated.
TIA -- Keith.Conversation Timers can be used to do something periodically or to do something after a fixed delay. You can either keep the same dialog you received the message came in on, set a timer and then send the message again when the timer message is received or else put the messages on a different queue and then process that queue periodically. The first option will require keeping the message body around somewhere - either by using retension on the queue or by keeping it in a seperate table (maybe indexed by dialogID).
Here's a little sample that uses timere to do something once a minute:
-- Set up a queue for the timer sample
CREATE QUEUE [TimerQueue]
CREATE SERVICE [TimerService] ON QUEUE [TimerQueue]([DEFAULT]) ;
CREATE SERVICE [TimerResponseService] ON QUEUE [TimerQueue];
GO
-- Create the stored procedure to handle the timer messages
CREATE PROCEDURE [dbo].[HandleTimer] AS
DECLARE @.conversationHandle uniqueidentifier
DECLARE @.message_type_name sysname
DECLARE @.dialog uniqueidentifier
BEGIN TRANSACTION
-- Timer messages only happen once a minute so there's no
-- need to receive in a loop.
WAITFOR (
RECEIVE top(1)
@.message_type_name=message_type_name,
@.dialog = conversation_handle
FROM [TimerQueue]
), TIMEOUT 500
IF (@.message_type_name = 'http://schemas.microsoft.com/SQL/ServiceBroker/DialogTimer')
BEGIN
-- Start the next cycle
BEGIN CONVERSATION TIMER ( @.dialog ) TIMEOUT = 60;
-- Do Whatever you want to do here
END
COMMIT TRANSACTION
go
ALTER QUEUE [TimerQueue] WITH ACTIVATION (
STATUS = ON, PROCEDURE_NAME = HandleTimer ,
MAX_QUEUE_READERS = 1,EXECUTE AS SELF)
go
DECLARE @.conversationHandle uniqueidentifier
BEGIN DIALOG CONVERSATION @.conversationHandle
FROM SERVICE [TimerResponseService]
TO SERVICE 'TimerService';
BEGIN CONVERSATION TIMER ( @.ConversationHandle ) TIMEOUT = 60;
