Why are Oracle Database Links being reported as down even when they are no longer available?

Why are Oracle Database Links being reported as down even when they are no longer available?

By default, if data for the Oracle Database Links is not available during the current poll, Applications Manager behaves as follows:
  1. Existing data (including thresholds) is retained
  2. Health status is reported as Down

For versions 173800 and above

You can configure this behavior directly from the UI:
  1. Navigate to Settings → Performance Polling → Optimize Data Collection → Oracle → Oracle DB Links
  2. Enable the Delete entry if it is not discovered 1 consecutive polls option.

For versions below 173800

Follow the steps given below to override this behavior:
  1. Open the AppManager_Home/working/conf/CustomMonitors/OracleDBServer.xml directory. Replace AppManager_Home with the actual directory path of Applications Manager.
  2. Locate the <OracleDBLinks> section and update RetainRowsOnDelete="YES" to RetainRowsOnDelete="NO".
  3. Decrement the version number found on top of XML file.
    4. InfoFor example: Change Version="18" to Version="17"
  4. Save the file and restart Applications Manager.