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Enable Tomcat Thread Queuing

When a request comes into the web server (Apache or IIS), the web server passes it to the application server. A finite number of application server threads are available for these connections, and when they have all been consumed, all additional requests will be dropped. This results in errors for the user, such as a page not loading. To add all additional requests to a queue instead of dropping them, enable Tomcat thread queuing. Although users might have to wait slightly longer for their request to be processed, they are less likely to have their request dropped.

Tomcat thread queuing can be enabled temporarily or permanently. If it is enabled temporarily, the change remains in effect only until a PushConfigUpdates command is run.

How to Temporarily Enable Tomcat Thread Queuing

  1. Stop the Blackboard Learn application.
    1. Open the bb-config.properties file in the following directory:

      UNIX:

      %/usr/local/blackboard_directory/config

      Windows:

      C:\blackboard_directory\config
       

    2. Change the value of the backlog attribute to at least 10 to increase the number of requests that will be placed on the Tomcat queue if no Tomcat threads are available to process a request from the web server. You may change increase this value as needed.

      bbconfig.appserver.backlog=10

      You may wish to confirm that "backlog=" in the server.xml.bb file is set to "@@bbconfig.appserver.backlog@@".

    3. Save and close the file.
    4. Restart the Blackboard Learn application.

    To make changes permanent, follow the steps in the next section.

How to Permanently Enable Tomcat Thread Queuing

  1. Open the bb-config.properties file in the following directory:

    UNIX:

    %/usr/local/blackboard_directory/config

    Windows:

    C:\blackboard_directory\config
     

  2. Change the value of the backlog attribute to at least 10 to increase the number of requests that will be placed on the Tomcat queue if no Tomcat threads are available to process a request from the web server. You may change increase this value as needed.

    bbconfig.appserver.backlog=10

    You may wish to confirm that "backlog=" in the server.xml.bb file is set to "@@bbconfig.appserver.backlog@@".

  3. Save and close the file.
  4. Update the configuration by running the PushConfigUpdates command:

    UNIX:

    %/usr/local/blackboard_directorytools/admin/ PushConfigUpdates.sh

    Windows:

    C:\blackboard_directory\tools\admin\ PushConfigUpdates.bat

To learn more, see PushConfigUpdates.