SQL触发批处理文件

Question

We are using SQL Server 2008R2 to handle a mail queue. New mail is entered into the queue and then once every minute a batch file reads the unprocessed mails, does some processing, sends the mail via smtp and flags the mail in the queue as sent (records is not deleted from queue because table also serves as mail history table).

The problem with this method is that it is run only once a minute so mails are not sent out "automatically", and the batch file runs every minute even when there is no outgoing mail for hours.

Is there a way for SQL server to run the batch file on each new item inserted into the mail queue? I know there are triggers but from what i understand they are asynchronous so if the batch file takes time it will hold up sql server

Answer 1

I would create a SQL server agent job to run the batch file using a cursor in the job in case there are multiple rows that are updated at once. Create a trigger on the table that runs the agent job. This won't hold up SQL server since it's running through SQL agent. The rows will be processed and the emails sent out immediately.

Answer 2

Are you talking about sending emails from SQL Server?

http://msdn.microsoft.com/en-us/library/office/aa155737(v=office.10).aspx

If so, just incorporate the send into your procedure.

If not, assuming you have IIS, don't try to do your own queue. Create a CLR procedure that adds the email to a .NET queue somewhere such as your batch server. You can then run a process on your batch server that to read the queue and send the email. Don't run it periodically - just keep it in a loop that does a blocking read the queue and sends mail. (You may have to add it to startup/run it periodically or something for resilience and DR reasons).