Requests Hang and Server Becomes Unresponsive With WLS Proxy Plug-In 12.2.1 for Apache 2.4 (Doc ID 2243419.1)

Last updated on AUGUST 17, 2017

Applies to:

Oracle WebLogic Server - Version 12.2.1.0.0 and later
Information in this document applies to any platform.

Symptoms

Requests hang when using Weblogic Server Proxy Plug-In 12.2.1 with Apache 2.4

For this case, testing showed the application hang while loading the a page (46 request/2.9MB) leaving some request in pending state in the browser (sending reply in the web server) than take several minutes to finish. There is no apparent pattern in the hanging requests, sometimes is a .js, others a .css. The fault or high response times only happens when the request are launched in parallel and the  weblogic plugin is included, it doesn't matter if that location is resolved directly in the web server.  It fails even when there is no request forwarded to weblogic server)

When calling the Apache status page at http://localhost:port/status , proxy requests are shown "stuck" in status "W", meaning "sending reply", but it remains this status.

A steady increasing amount of connections are seen and when all Apache processes are consumed, the Apache Server becomes unresponsive.

Changes

To reproduce quickly, you may use "Apache Bench" to create some heavy load:

Example usage:
$ ab -n 1000 -c 20 "http://apache.example.com/Hello.jsp"
This will execute 1000 HTTP GET requests, processing up to 20 requests concurrently to the specified URL.

Now review the Apache status page and discover, 2 connections are still in status "W" (Sending reply).

Cause

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