'Oc4jselectmethod roundrobin:weighted' Results in HTTP-500 Errors When An OC4J Instance is Down
(Doc ID 731531.1)
Last updated on FEBRUARY 01, 2022
Applies to:
Oracle HTTP Server - Version 10.1.3.0.0 to 10.1.3.4.0 [Release AS10gR3] Information in this document applies to any platform.
Symptoms
Oracle Application Server 10g 10.1.3.X.X is installed in a distributed topology
The topology contains three Oracle Homes - 'ohs only' (ohs1), 'oc4j only' (oc4j1) and another 'oc4j only' (oc4j2). The two oc4j homes are on separate nodes.
A J2EE application is deployed to a group consisting of two OC4J instances
First, using the default Oc4jSelectMethod roundrobin in mod_oc4j.conf, the application is accessed and a note of the active OC4J instance is noted.
Next, the active OC4J instance is shut down cleanly from Application Server Control or using opmnctl
In this case, a clean failover occurs to the other available OC4J instance in the group.
If a weighted load-balancing scheme is used instead of the default random such as :
http://<HOST>:port/oc4j-status shows correctly that only one oc4j instance is available,so the notification is being received by HTTP Server.
After some time, or after a restart of OHS, new requests are successfully routed to the available OC4J instance.
The problem reproduces if the ons discovery method is static or dynamic.
The problem reproduces if the oc4j mount points are static or dynamic
Cause
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