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Distributed Queue System using Gearman


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We use Gearman for managing queue system. This covers why we should use a queue in many situations on web-based interface as well as server-side application.

We use Gearman for managing queue system. This covers why we should use a queue in many situations on web-based interface as well as server-side application.

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  • 1. Distributed Queue System using Gearman Taehun Cho CTO @ IMcompany
  • 2. What is a Queue? copyright@
  • 3. Multiple Queue With multiple teller, all customers must form multiple queue to be served
  • 4. Some Situation on the WEB+You want to send an email, push notification,messages, import big file, etc...
  • 5. Problem is that... DO NOT LET YOUR USERS WAIT
  • 6. Run Asynchronously
  • 7. Running Task in a Single Thread? Loading behavior may affect the main GUI
  • 8. Run in Background!The user can do next action, and the task should be done in backend in a distributed manner
  • 9. Job Queue SystemsCelery ( ( Server Job Queue ( (, StarlingApache ActiveMQand many others..
  • 10. Introducing Gearman LiveJournal
  • 11. Introducing GearmanIn LiveJournal, many photos had uploadedevery day and it lead to a heavy load of imageprocessing, and this was a motivation to buildsuch a queue system.● Yahoo!: 120+ servers, 12M jobs/day● Digg: 45+ servers, 400K jobs/day● LiveJournal, SixApart, DealNews,, and many others. - Expert PHP and MySQL - Andrew et al, (2010, Wrox)● Grooveshark,, IMcompany
  • 12. Features of Gearman● Open Source● Simple & Fast (rewritten in C)● Support a variety of languages : build Worker in Python, Client in PHP● Flexible● Load Balance● Failover
  • 13. Example of Architectures (from
  • 14. Architecture Acks the job, finds all sleeping workers Awake, asks for jobs to server Gearman Job ServerConnect, submit a job Sends a noop command to wake them up Client Worker
  • 15. Installation● Compile (for PHP APIs)tar xzvf gearmand-X.Y.tar. ● Pecl Extensiongz sudo pecl install gearmancd gearmand-X.Y./configure ● Add below to php.inimake extension=""make install● Start Server$ gearmand -d
  • 16. Use Cases- Crawling a website- Image Manipulation- Push Notification- Sending Email/Messages- File verification/compressing- Fetching RSS Feeds- Indexing on Search Engine
  • 17. Samples - Worker
  • 18. Samples - Client
  • 19. Samples - Monitoring A good tool for monitoring gearman, is available at
  • 20. Result Worker #1 Worker #2The incomplete job will re-queue to available workers for fault-tolerance
  • 21. Motivation● At the beginning state, we run 3 computers for crawling each schools information. (articles, schedules of the school)● One job at a time, too much time to finish all of them, sometimes machines do the same job as the others do.● That was a motivation to make a job queue system that could do jobs in parallel. And weve found Gearman!
  • 22. Gearman in IMcompanyBut there were some challenges!● How many workers should be up for a server? (How efficiently leverage the load?)● How can we handle unexpected termination of workers?● What if the servers resource is exhausted due to the jobs that given by workers? (Then the server would not respond to others requests/connections related to WEB, SVN, MySQL)
  • 23. Exceptional Case #1
  • 24. Reported bugs when using PHPBug #63041 "Failed to set exception option" onconnect when any gearman server is down #63648 Gearman worker stops withsegfault after 1-2 hour of working
  • 25. Supervisord for sanity"PHP was not built for long running request""Sometimes it occurs memory leaks"Supervisord helps you in above cases!- Auto restart the processes based on customconfigurations* Installation guide -
  • 26. Exceptional Case #2 PHP sometimes slows down after hundreds of executions, kill it off if you know this will happen. - Mike Willbanks, "Gearman: A Job Server made for Scale"
  • 27. Server Seems Fine for Now
  • 28. What We Learned● Gearmans queue list is unstable so persistent queueing was highly needed in our system● Integrating MySQL with Gearman was failed in both 1.0.2, 0.34● Tried SQLite, but performance was very poorDo NOT Reserve Too Much Jobs in a Queue
  • 29. Also Weve Tried...● Firing queueing jobs over HTTP request is sometimes not working and may lead to freezing the server eventually● And doesnt support additional functions for the HTTP connection such as authentication● And is not customizableGearman Seems Too Young at This Moment
  • 30. Limitations● Queue makes no guarantees - use MySQL, memcached, Redis, PostgreSQL, etc..● There are few administration tools● Jobs dont expire● If a job is dropped, the client is never be notified-from ""
  • 31. Join Community!
  • 32. Were hiring!● Work in Daejeon, Korea● Flexible, Small Company● Excellent Benefits● We Need Senior HackersFind more information at you!Any questions?