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Database Crashes With ORA-00494 (Doc ID 753290.1)

Last updated on AUGUST 04, 2018

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.4 to 11.2.0.4 [Release 11.2]
Oracle Database - Enterprise Edition - Version 10.1.0.5 to 12.1.0.1 [Release 10.1 to 12.1]
Information in this document applies to any platform.
***Checked for relevance on 09-July-2014***

Symptoms

Database may crash with the following error in the alert file (in 11g xml format):

ORA-00494: enqueue [CF] held for too long (more than 900 seconds) by 'inst 1, osid 20725'

This error can also be accompanied by ORA-600 [2103] which is basically the same problem - a process was unable to obtain the CF enqueue within the specified timeout (default 900 seconds).

This behavior can be correlated with server high load and high concurrency on resources, IO waits and contention, which keep the Oracle background processes from receiving the necessary resources.

Call stack
==============
[01]: kjdgpstackdmp []<-- Signaling
[02]: kjdglblkrdmpint []
[03]: ksikblkrdmp [KSI]
[04]: ksqgtlctx [VOS]
[05]: ksqgelctx [VOS]
[06]: kcc_get_enqueue []
[07]: kccocx []
[08]: kcc_begin_txn_internal []
[09]: krsaibcx []
[10]: kcrrcrl_dbc []
[11]: kcrrcrlc []
[12]: kcrrwkx []
[13]: kcrrwk []
[14]: ksbcti [background_proc]
[15]: ksbabs [background_proc]
[16]: ksbrdp [background_proc]
[17]: opirip []
[18]: opidrv []
[19]: sou2o []
[20]: main []
[21]: _start []

In the System State Dump you can find this short stack
=======================================
kaio<-aiowait<-skgfospo<-skgfrwat<-ksfdwtio

Cause

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In this Document
Symptoms
Cause
Solution

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