Slow Response OEM Agent Causes MMON Hung with "EMON to process ntnfs"

(Doc ID 2308245.1)

Last updated on NOVEMBER 21, 2017

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.4 and later
Enterprise Manager for Oracle Database - Version 11.2.0.4 and later
Information in this document applies to any platform.

Symptoms

In 2 Nodes RAC environment, AWR snapshot interval is set to 15 minutes, but snapshots were missing for long time.
e.g.
In Node#1, 2016/11/17 00:15~2016/12/27 10:45
In Node#2, 2016/11/18 05:45~2016/12/27 10:45

Within such a long missing duration, there is no any ORA-12751 error or Suspending MMON slave action message.

After that period, ASH emergency flush was done in both nodes.

 

And from available ASH information of both nodes, there are significant waiting events of 'wait for EMON to process ntfns' of MMON process in Node#1,
and 'reliable message' of MMON slave processes in Node#2.

And this problem was improved after OEM agents restart.

And in this environment, Bug 18148383's patch has been applied.

Bug 18148383 AWR snapshots stopped , MMON hung with "EMON to process ntnfs"


P.S. For security, all key information of customer environment are masked by XXXXX, YYYYY, ZZZZ, etc.

Cause

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