Sunil's Notes: Configure Portlet Load monitoring for maximum response time

The WebSphere Portal Server 7.0 introduced concept of portlet load monitoring, it lets you set maximum response time for a portlet and if the response time exceeds that time, WPS will block that portlet and would disable further request to that portlet.

I wanted to try this feature so i followed these steps

First enable Portlet load monitoring at portal server level

Then i created HelloPLM simple portlet that takes 10 seconds to respond.


package com.wpcertification.wp70.plm;
import java.io.IOException;
import javax.portlet.GenericPortlet;
import javax.portlet.PortletException;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;
public class HelloPLMPortlet extends GenericPortlet{

  protected void doView(RenderRequest request, RenderResponse response)
      throws PortletException, IOException {
    System.out.println("Entering HelloPLMPortlet.doView()");
    try {
      Thread.sleep(10000);
    } catch (InterruptedException e) {
      e.printStackTrace(System.out);
    }
    response.setContentType("text/html");
    response.getWriter().println("Inside HelloPLMPortlet.doView()");
    System.out.println("Exiting HelloPLMPortlet.doView()");
  }
}

In the doView() method i am using Thread.sleep() call to block request for 10 seconds. You can download this sample application from here

Then i installed the portlet on the WPS 70 server

Once the portlet is installed, you can enable PLM for it by setting com.ibm.wps.pe.plm.average.time.processing preference. Value of this preference defines what is the maximum allowed time for this portlet. Example: If you want to specify the average response time allowed for a portlet as 3 seconds, set the portlet preference com.ibm.wps.pe.plm.average.time.processing to a value of 3000 (milliseconds) for this portlet. If portlet takes more than that time it will blocked

In my case i am setting the maximum allowed time to 900 milliseconds which is less than 1 second

After setting the preference when i looked at the portlet in manager portlet, i could see that it had one additional button that would let me block the portlet manually

Then i went to a page which has HelloPLM portlet and it took 10 seconds to respond and on the first request it did render the output correctly but in the SystemOut.log file i could see this message
[9/4/10 17:34:26:927 PDT] 00000067 GlobalPortlet W com.ibm.wps.pe.pc.waspc.plm.GlobalPortletLoadMonitoringFilter handlePreFilterInvocation() EJPPG3002W: Portlet Load Monitoring disabled the portlet with object ID: [ObjectIDImpl 'Z3_OGFLMKG10G0HE0IAR5N7GE3007', PORTLET_DEFINITION, VP: 0, [Domain: rel], DB: 0000-18BE6A290C0082E88054BBDC03DD00E0], portlet name: Hello PLM portlet, WAR file name: HelloPLM.war, EAR file display name: PA_HelloPLM because the portlet exceeded its average response time.
The HelloPLM portlet took more than the allowed time so it was disabled

Now when i went to Manage portlet, portlet i could see that the portlet is disabled, from the request you can see that the portlet exceeded limit

Now if i go to the page which has the HelloPLM portlet, then i directly get portlet unavailable message without the portlet being called at all

You can unblock the portlet from Portal Admin Console

Configure Portlet Load monitoring for maximum response time

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