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WebLogic Server Work Managers and Overload Protection


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A tour of the WebLogic Server work manager and self-tuning thread pool features that automatically adjust to changing workloads and protect the server from overload conditions.

A tour of the WebLogic Server work manager and self-tuning thread pool features that automatically adjust to changing workloads and protect the server from overload conditions.

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  • So in this example, if another fair share was assigned a value of 20, the ration would be 80:20 or 4:1. This means that if each application has the same amount of requests coming in and there are not enough threads to server all requests immediately, then high-fair share work manager will get 4x as many requests serviced as the low-priority work manager.
  • Transcript

    • 1.
    • 2. WebLogic Server Work Managers
      James Bayer
      WebLogic Server Product Management
    • 3. Agenda
      WebLogic Server Work Manager Overview
      Feature Demonstration
    • 4. <Insert Picture Here>
      WLS Work Manager
    • 5. Real World Overload Protection
    • 6. WebLogic Server Overload Protection
      Examples where this is applicable
      • Protect against cascading failures
      • 7. If maximum number of Database connections are in use, do not allocate new threads to service web requests that need a database connection
      • 8. Protect against hogging applications
      • 9. If multiple applications are deployed to the same server, ensure badly behaving applications do not consume all resources
    • Work Management ConcernsOptimally tuning servers is hard!
      Thread pool size for optimum performance?
      Workload can vary (time of day, event driven, etc.)
      Handle overloadconditions gracefully
      Prioritization of work
      Across modules within single application
      Across multiple applications
      Across multiple classes of users
      Ordered processing of requests (one request at a time)
    • 10. Typical SolutionsWork Management Concerns
      Overprovision resources
      Size thread pools for maximum load factor, usually requiring many load-test runs to optimize
      WLS 8.1 - configure multiple execute queues
      Deploy applications into different server instances
      Build additional machinery to detect overload condition and react
      => Sub-optimal ROI and increased Complexity
    • 11. WebLogic Server Work Managers
      • Indicate your intent
      • 12. WebLogic is on autopilot adjusting to meet your goals
    • WebLogic Server Work ManagersCore Principles
      Work Prioritization
      Applications define resource requirements via meta-data they can relate to, rather than low-level technical constructs (thread counts)
      User-specific SLAs can be defined
      Thread Pool Management
      Applications should not have to configure and maintain thread pools
      WLS manages this internally and automatically
      Without necessarily requiring Administrator configuration and sizing input
      Overload Protection
      Standardized mechanism to respond to overload conditions
    • 13. WLS Work ManagementKey Components
      New Thread Pool Implementation
      Single internally managed thread pool and priority-based request queue service all application requests
      Request “Priority” dynamic and internally computed to meet application-defined goals
      Thread Count Self-Tuning
      Self-tuning thread pool monitors overall throughput every two seconds
      Present thread count, measured throughput, and past history determines if thread count needs to change
      New threads automatically added/removed as needed
      Benefits Administrators and Operators - no need to conduct tedious performance testing or guesswork just to pick a static thread pool size that does not adapt to changing workloads
    • 14. WLS Work ManagementKey Components
      Work Managers
      Runtime abstraction used by applications to define resource requirements
      Work Manager Components
      Request Class
      Fair-Share – desired share of server resources for app
      Response Time –desired app response time
      Context Based – user-specific SLAs
      Minimum Thread Constraint
      Maximum Thread Constraint
      Specified in application descriptor (weblogic.xml, weblogic-ejb.xml, weblogic-application.xml)
      Can be accessed programmatically via CommonJ API – JSR-237
    • 15. Work Manager Examples
      Fair Share
      Desired share of server resources
      Thread usage become higher as fair share number increases
      Fair shares are relative to other fair shares defined in the system
    • 16. Work Manager Examples
      Response Time Goal
      Desired response-time goal in milliseconds
      Response-time goals relative to other response goals and fair shares
    • 17. Work Manager Examples
      Currently look at security name and group of user submitting the request
      <work-manager> <name>context_workmanager</name>
      <request-class-name>high_fairshare</request-class-name> </context-case>
      <request-class-name>low_fairshare</request-class-name> </context-case>
    • 18. How to use Work Managers
      • Coarse Grained
      • 19. Target at the entire server (“default” Work Manager)
      • 20. Target entire applications or modules - e.g. weblogic.xml
      • Fine Grained
      • 21. Target individual JSPs, Servlets, EJBs, MDBs
      <servlet> ...
      <param-value>myCustomWorkManager</param-value> ...
      • Programmatically via JNDI lookup
      InitialContextic = new InitialContext(); wm = ("java:comp/env/wm/myWM");
    • 22. Stuck Threads
      • A Label given to threads not returned to thread pool after a configured period of time (defaults to 600 secs)
      • 23. Does not mean threads are literally stuck or locked (although possible) – they might be performing a long-running task
      • 24. This is an informational label – Administrators cannot stop the threads directly due to Java Threading design
      • 25. The Server or the Work Managers can be configured to shutdown or go to an Admin State once a certain number of threads become stuck
    • <Insert Picture Here>
      WLS Work Managers Demonstration
    • 26. Demonstration Application
      Web Application
      veryslow.jsp – 30 second sleep
      Work Manager targeted at veryslow.jsp
      Max Thread Constraint = 5
      Capacity Constraint = 7
      Test Scenario
      10 concurrent clients access veryslow.jsp (using JMeter)
      Work Manager controls how clients get serviced
      7 clients – OK
      3 clients – HTTP 503 (“Server Busy”)
    • 27. WLS behavior under test scenario
    • 28. Test Results
    • 29. Image Attribution
      • Photo of Circuit Breaker courtesy of Alan Hochberg
      • 30.