Troubleshooting Oracle EBS R12.2 Login Page Hang Caused by WebLogic OACORE

Introduction

One of the common issues Oracle E-Business Suite (EBS) administrators face is the login page hanging or failing to load. In many cases, the root cause is excessive resource consumption by a WebLogic OACORE managed server. This blog walks through a real-world troubleshooting approach to identify, analyze, and safely resolve such issues in EBS R12.2 environments.

Problem Overview

Users reported that the EBS login page was not loading. Server-level investigation revealed that a specific Java process related to OACORE was consuming unusually high CPU resources, causing system slowdown and application unresponsiveness.

Step 1: Identify High Resource Utilization

Start by checking overall system performance using the top command.

Key observations:

  • Load average was significantly high

  • CPU usage was dominated by user processes

  • A Java process owned by applmgr was consuming excessive CPU

This immediately indicates a potential WebLogic-related bottleneck.

Step 2: Confirm the Process Belongs to OACORE

Using the process ID identified from top, verify whether it is an OACORE managed server.

ps -fp <PID> | grep -i oacore

The output confirms that the Java process corresponds to oacore_server2, validating that the issue is WebLogic OACORE-related.

Step 3: Analyze Historical CPU Trends

To understand whether the issue is a spike or a recurring pattern, review system activity reports using sar.

sar -f /var/log/sa/saXX

Findings:

  • Sustained high CPU usage

  • Increased I/O wait during the affected time window

This indicates prolonged system stress rather than a short-lived anomaly.

Step 4: Check WebLogic Incident Directories

Oracle WebLogic automatically generates incident reports when it detects internal issues such as thread hangs or performance degradation.

Navigate to the OACORE incident directory:

$FMW_HOME/user_projects/domains/EBS_domain/servers/oacore_server2/adr/diag/ofm/.../incident

Multiple incdir_* directories suggest repeated incidents.

Step 5: Review Incident Details

Inside the latest incident directory, you’ll typically find:

  • JVM thread dumps

  • DMS metrics

  • ODL logs

  • A detailed readme.txt

These files are extremely valuable for root cause analysis and Oracle SRs.

Step 6: Analyze the Incident Readme

The readme.txt file provides a summary of what triggered the incident—often pointing to stuck threads, long-running SQL, or memory pressure within OACORE.

This confirms that the login issue is not network-related but tied to backend processing.

Step 7: Identify Problematic SQL Executed by OACORE

To pinpoint the exact database activity causing the slowdown, query active OACORE sessions:

SELECT sid, serial#, sql_id, event, seconds_in_wait
FROM v$session
WHERE program LIKE '%oacore%'
AND status = 'ACTIVE';

Once the SQL ID is identified, retrieve the full SQL text:

SELECT sql_text
FROM v$sql
WHERE sql_id = '<sql_id>';

This step helps determine whether the issue is due to inefficient SQL, locking, or application behavior.

Additionally, check for repeating WebLogic errors:

grep -i "BEA-000337" oacore_server2.log | tail

Recurring messages usually indicate thread contention or stuck executions.

Step 8: Immediate and Safe Mitigation

If users are actively impacted, apply one of the following safe recovery options:

Option 1: Kill the Problematic Process

kill -9 <PID>

(This forces OACORE to restart automatically.)

Option 2: Gracefully Restart OACORE

sh admanagedsrvctl.sh stop oacore_server2
sh admanagedsrvctl.sh start oacore_server2

A controlled restart is recommended in production environments.

Conclusion

EBS login page hangs are often symptoms of deeper WebLogic OACORE performance issues. By systematically analyzing system load, WebLogic incidents, and database activity, administrators can quickly isolate the root cause and restore service with minimal disruption.

Proactive monitoring of OACORE logs and incident directories can help prevent such outages in the future.

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