In this Document
| Symptoms |
| Changes |
| Cause |
| Solution |
| References |
APPLIES TO:
Oracle Database - Enterprise Edition - Version 11.1.0.7 to 11.2.0.3 [Release 11.1 to 11.2]Information in this document applies to any platform.
SYMPTOMS
- RAC Instances freezes during DRM for 100 secs or more.
- DB Alert log shows that all RAC instances undergo reconfiguration at the same time, but there are no instance crashes
| Node 1 DB Alert Log | Node 2 DB Alert Log |
|---|---|
| Sat Jul 14 14:17:04 2012 Reconfiguration started (old inc 70, new inc 72) List of instances: 1 2 (myinst: 1) Global Resource Directory frozen Communication channels reestablished Master broadcasted resource hash value bitmaps Non-local Process blocks cleaned out Sat Jul 14 14:17:04 2012 LMS 1: 0 GCS shadows cancelled, 0 closed, 0 Xw survived Sat Jul 14 14:17:04 2012 LMS 0: 0 GCS shadows cancelled, 0 closed, 0 Xw survived Set master node info Submitted all remote-enqueue requests Dwn-cvts replayed, VALBLKs dubious All grantable enqueues granted Sat Jul 14 14:17:13 2012 minact-scn: Master returning as live inst:2 has inc# mismatch instinc:70 cur:72 errcnt:0 |
Sat Jul 14 14:17:04 2012 Reconfiguration started (old inc 70, new inc 72) List of instances: 1 2 (myinst: 2) Global Resource Directory frozen Communication channels reestablished Sat Jul 14 14:17:04 2012 * domain 0 valid = 1 according to instance 1 Master broadcasted resource hash value bitmaps Non-local Process blocks cleaned out Sat Jul 14 14:17:04 2012 LMS 0: 0 GCS shadows cancelled, 0 closed, 0 Xw survived Sat Jul 14 14:17:04 2012 LMS 1: 0 GCS shadows cancelled, 0 closed, 0 Xw survived Set master node info Submitted all remote-enqueue requests Dwn-cvts replayed, VALBLKs dubious All grantable enqueues granted Sat Jul 14 14:18:03 2012 Submitted all GCS remote-cache requests |
- Lmon trace shows that DRM quiesce step hangs:
*** 2012-07-14 14:14:51.187
CGS recovery timeout = 85 sec
Begin DRM(231) (swin 1)
* drm quiesce
*** 2012-07-14 14:17:03.752
* Request pseudo reconfig due to drm quiesce hang
2012-07-14 14:17:03.752735 : kjfspseudorcfg: requested with reason 5(DRM Quiesce step stall)
*** 2012-07-14 14:17:03.766
kjxgmrcfg: Reconfiguration started, type 6
CGS/IMR TIMEOUTS:
CSS recovery timeout = 31 sec (Total CSS waittime = 65)
IMR Reconfig timeout = 75 sec
CGS rcfg timeout = 85 sec
kjxgmcs: Setting state to 70 0.
- AWR Top waits are "gcs resource directory to be unfrozen" & "gc remaster"
CHANGES
Large Buffer Cache
CAUSE
This is caused by bug:
Bug 12879027 - Lmon trace file shows that Pseudo reconfigurations triggered by the DRM are hanging. DRM quiesce is timing out..
DRM has a number of steps. During the DRM quiesce step all ongoing block transfers for remastering are completed.
In this case, during the DRM quiesce step a hang occured due to an internal function hitting a timeout.
This is a bug condition that happens when the buffer cache is very large.
This hang then triggers a pseudoreconfiguration to prevent the instance from being killed by another instance.
This is the reason for the instance undergoing a reconfiguration without restarting.
SOLUTION
Apply the fix for bug 12879027.
This issue is fixed in the following DB PSU patches:
Patch 13923374 - 11.2.0.3.3 DB Patch Set Update (PSU)
Patch 13923804 - 11.2.0.2.7 DB Patch Set Update (PSU)
Also bundled in the corresponding GI PSU
REFERENCES
NOTE:756671.1 - Oracle Recommended Patches -- Oracle DatabaseNOTE:390483.1 - DRM - Dynamic Resource management
BUG:12879027 - LMON PROCESS CAN GET STUCK IN DRM QUIESCE STEP TRIGGERING PSEUDO RECONFIGURATION
