I've setup an Oracle Database availability monitor/alert. I created an Oracle End User experience monitor that sends a query to our Oracle database to confirms its up.
The query is 'SELECT 1 FROM DUAL'. If this query returns 1, that means the database is up. If it doesn't, that means the database is down.
The alert I have setup polls every 5 minutes and I'll occasionally get false-positive down alerts for. These alerts all come from the same node and every time I am alerted, my Oracle DBA confirms that the database is indeed running.
I've already confirmed that the metrics for this node look good, so I'm thinking it has something to do with the Oracle database itself. This same monitor/alert has also been setup for a bunch of other databases on other nodes but they don't throw these false-positives.
Does anyone have any insights or suggestions on how to troubleshoot this?