How to Purge Workflow Notifications from Mailer Queue, so that Email is not sent to Users?

What to do when Workflow Notification  Mailer was not running properly for a certain period of time and accumulated all the emails in Workflow Queue.
We can Purge the workflow Mails which are not required by updating mail_status='SENT' for unwanted notifications in wf_notifications table.

Here are a couple of reasons to Purge Workflow Notifications

a)The end user may not want to receive outdated email.
b)The Workflow Queue has accumulated a lot of emails during the issue period, and processing has become very slow.

Below are the steps to Purge Workflow Notifications which are not required

1.First Take a Backup of wf_notifications table  and stop the Workflow Notification Mailer

2. Verify notifications from WF_NOTIFICATIONS table that has potential for being sent

SQL> select notification_id, recipient_role, message_type, message_name, status, mail_status
     from wf_notifications
     where status in ('OPEN', 'CANCELED')
     And Mail_Status In ('MAIL', 'INVALID')
     order by notification_id;
   
3. Narrow down the emails which are not to be sent by the Mailer from a specific date range.

SQL> select notification_id, begin_date, recipient_role, message_type, message_name, status, mail_status
     from wf_notifications
     Where Status In ('OPEN', 'CANCELED')
     And Mail_Status In ('MAIL', 'INVALID')
     and begin_date < sysdate-30              -- List only emails older than 30 days ago
     order by notification_id;

4. Set Mail_status='SENT' in WF_NOTIFICATIONS

SQL>update WF_NOTIFICATIONS set mail_status = 'SENT'
where mail_status in ('MAIL','INVALID')
and Status In ('OPEN', 'CANCELED')
and begin_date < sysdate-30;      

SQL>Commit;


This will update  notifications ,which are older than 30 days and waiting to be sent by the mailer to SENT.
Therefore the notifications will not get emailed when the Mailer is restarted.

5.Run the script $FND_TOP/patch/115/sql/wfntfqup.sql to purge the WF_NOTIFICATION_OUT queue and rebuild it with data currently in the WF_NOTIFICATIONS table. This is what purges all notifications waiting in the queue to be sent.  It will then populate the queue with the current data in the wf_notifications table.
Since you have changed the mail_status = 'SENT" it will not enqueue these messages again.. Only the ones where mail_status = 'MAIL' and status = 'OPEN' will be placed in the WF_NOTIFICATION_OUT queue and sent by the mailer. (or CANCELED and INVALID if certain concurrent reports are run)

Example :
$ sqlplus usr/passwd@db @$FND_TOP/patch/115/sql/wfntfqup.sql APPSusr APPSpw FNDusr


Example Syntax:
$ sqlplus apps/***@db @$FND_TOP/patch/115/sql/wfntfqup.sql apps ***** applsys


6.Now start the Workflow Notification Mailer.