I am using 11g, but this work in 10g as well.I had this annoying alert appearing under my alert tab on OEM for some time. A failed job, yes I knew it failed and fixed it that day. I waited for the alert to disappear, but alas, it did not. I acknowledged it and thought that was the end of that. Well it's been hanging around for some time and when I click on it the alert it take me to a jobs page with no information on how to clear.
I started hunting around for information on how to clear alerts that have no purpose in OEM and I found a lot of posting that said to log in as sysman and query the mgmt_current_severity and then use em_severity.delete_current_severity to remove the desired alert.
Okay that sounds good, but then I found a post by a Said Ahmed. He posted the following query which I found to be very useful so here it is.
First log in as SYSMAN or your repository owner.
, 'exec em_severity.delete_current_severity(''' ||
t.target_guid || ''',''' ||
metric_guid || ''',''' ||
key_value || ''')' em_severity
from sysman.mgmt_targets t
t.target_guid = s.target_guid;
This will give you information about all the alerts in OEM. Copy the result from the em_severity column that you want removed. Run it exactly as it appears. Be sure you are logged in as sysman.
SQL> exec em_severity.delete_current_severity('stuff','moretuff','SCHEMA')