AWR Snapshots Fail to Generate With Associated "Suspending MMON action '%s' for 82800 seconds" alert log messages and Underlying ORA-12751 Errors
(Doc ID 2043531.1)
Last updated on JUNE 29, 2021
Applies to:Oracle Database - Enterprise Edition - Version 10.2.0.4 and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this document applies to any platform.
You may observe any one or more of the following messages:
- AWR snapshot generation stopped all of a sudden (this can occur on both RAC or a non-RAC databases).
- Alert log shows messages indicating that MMON has been disabled for 82800 seconds (23 hours). During these 23 hours, no new AWR snapshots will be generated automatically.
- Looking in MMON or MMON (M00X) slave trace files, ORA-12751 errors can be seen with text such as "Runtime exceeded <N> seconds".
MMON trace sample (xxxxx_mmon_11976.trc):
This example shows a 900 second (15 min) timeout that caused MMON to be suspended.
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