High Library Cache Pin and Repeated "DRM(nn) ignoring dissolve of nnnnnnnn since no pt exists" in RAC Environment (Doc ID 1471060.1)

Last updated on OCTOBER 13, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 11.1.0.6 and later
Information in this document applies to any platform.

Symptoms

 
1. High 'library cache pin ' waits as seen in AWR:


Top 5 Timed Events                                               Avg %Total
~~~~~~~~~~~~~~~~~~                                              wait   Call
Event                                       Waits    Time (s)   (ms)   Time
------------------------------------ ------------ ----------- ------ ------
library cache pin                       1,360,739     220,350    162   52.7
latch free                              2,124,611      59,834     28   14.3
..


2. At same time as the high library cache pin waits, the  lmd tracefile has MANY entries like the following every second:

 *** 2012-01-03 17:57:02.626
 DRM(39) ignoring dissolve of 4845440 since no pt exists
 DRM(39) ignoring dissolve of 37847552 since no pt exists
 DRM(39) ignoring dissolve of 12959360 since no pt exists
 DRM(39) ignoring dissolve of 25428224 since no pt exists
 DRM(39) ignoring dissolve of 13003136 since no pt exists
 DRM(39) ignoring dissolve of 13252352 since no pt exists


3. Much less library cache pin waits  if DRM is disabled

 

4. Call stack for lmd at the time that the high waits has the following:

  kjdrchkdrm-> kcluseobjscan-> kclbufs

 

Cause

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