Launching A Worksheet In Discoverer 10g / 11g Plus/Viewer On Linux Fails With 'Contact with backend server lost'

(Doc ID 871012.1)

Last updated on OCTOBER 03, 2016

Applies to:

Oracle Discoverer - Version and later
Linux x86
SUSE \ UnitedLinux x86-64
Linux x86-64
***Checked for relevance on 24-Jan-2014***


Trying to run any worksheet in Discoverer Plus or / Viewer gives error:

Query execution was not successful.
- Contact with backend server lost
OracleBI Discoverer Viewer was unable to find the necessary data for displaying the results of
this event. Please correct any errors and try again.
- Session closed

Other symptoms may include:

If a Discoverer Viewer user exits the browser abnormally (i.e. - click the X and close the browser) rather than exit the application via the 'exit' link this will leave a Discoverer dis51ws session open on the middle-tier server (normal so far); however, the user will not be able to log back in when starting a new browser session. The session will continuall refresh and timeout with a corba error.

Attempt 1. CORBA proto    : 0 of 1 processes started.
Hint: An administrator can further diagnose connection problems by running
the "checkdiscoverer" script under <ORACLE_HOME>/discoverer/util

Error in $ORACLE_HOME/opmn/logs/OC4J_BI_Forms-default-island-log shows:

09/06/09 13:08:34 BI Beans Graph version []
<2009060913082913801>: Unexpected exception in state machine: DiscoNetworkException - Nested exception: org.omg.CORBA.COMM_FAILURE: vmcid: SUN minor code: 208 completed: Maybe
09/06/09 13:08:35 Tue Jun 09 13:08:35 CEST 2009 PROBLEM: In oracle.disco.bibeans.SchedulableQueryExecutor::_runQuery: Internal DataSource/Beans error: Query failed:



Error in $ORACLE_HOME/j2ee/OC4J_BI_Forms/application-deployments/discoverer/OC4J_BI_Forms_default_island_1/application.log shows:

09/06/09 13:08:36 discoverer: [ERROR] [AJPRequestHandler-ApplicationServerThread-23] oracle.discoverer.applications.framework.ApplicationController._logException
at oracle.discoverer.applications.viewer.view.dataprovider.WorksheetProxy.retrieveWorksheetData(Unknown Source)
at sun.reflect.GeneratedMethodAccessor232.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(
at java.lang.reflect.Method.invoke(
... ... ...



The dis51ws Discoverer session executable/process causes a "segfault error" on the system when the error occurs and/or the dis51ws executable will produce a core dump file (if ulimit -c is greater than 0)

For example, message in /var/log/messages shows:







The problem can start occurring when enabling Discoverer to use the Query Governor, for example, when setting QueryTimeLimitEnabled=1 in $ORACLE_HOME/discoverer/util/pref.txt


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