Automic Workload Automation

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The COLD start 'HOT' topic

VidyaPraveenBatchu605049

VidyaPraveenBatchu605049Sep 27, 2016 12:37 AM

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Legacy UserSep 29, 2016 11:18 PM

  • 1.  The COLD start 'HOT' topic

    Posted Sep 07, 2016 05:44 AM
    Just a few considerations about the COLD start.

    What is a COLD start ?
    > A COLD start will clear out the MQ (Message Queue) tables, that are used by server processes (CPs and WPs).

    When should a COLD start be performed ?
    > Usually after updating the Automation Engine server (binaries and database).
    > Sometimes, old messages can be left in the MQ tables causing the Automic system to not be able to start correctly, or freeze.  The most common reason for this is if the Automic system has been brought down ungracefully.

    Does a COLD start impact task processing?
    > All tasks which were executing any script (status: "generating", "post-processing", etc.) will be in status "inconsistent" after the cold start.
    > All "open" statistic records (without end - timestamp) will be checked. If they are no longer in activity window they will get a end time stamp.

    How to perform a cold start ?
    > I listed 3 different ways of doing it in this post.

    Special thanks to Josef_Scharl_103 who gave me some insights before writing this post.

    Please feel free to share your experience  / knowledge over the cold start...



  • 2.  The COLD start 'HOT' topic

    Posted Sep 14, 2016 07:50 AM
    add point 1) all MQ tables are truncated except the MQSRV table, sometimes you will have to truncate this table manually.


  • 3.  The COLD start 'HOT' topic

    Posted Sep 21, 2016 04:30 PM
    thanks for this info , In case if required how to truncate this mqsrv table.?


  • 4.  The COLD start 'HOT' topic

    Posted Sep 22, 2016 02:35 AM
    Antoine_Sauteron Thanks man - thats very interesting and useful!


  • 5.  The COLD start 'HOT' topic

    Posted Sep 22, 2016 06:28 AM
    Thanks for this nice article, so does this mean if we truncate all the MQ Tables manually and we start the system again with "StartMode=Normal", are these actions same as cold start ?


  • 6.  The COLD start 'HOT' topic

    Posted Sep 23, 2016 02:39 AM
    No, cold start does "initialize" the AE new.

    Especially after a change of AE binaries and/or DB content (Initialdata) a COLD start is a must. There is no way around it :-)


  • 7.  The COLD start 'HOT' topic

    Posted Sep 23, 2016 09:45 AM
    Here is some additional input about what the COLD start does:
    • Removes every message from the message queues, which prevents all active workflows and tasks from being further processed
    • Tasks turn into an inconsistent state and then need to be manually cleaned up
    • Agents will be forced to reconnect
    • Every time dependency will be recalculated


    In summary it puts the automation processing in an inconsistent state which enforces manual intervention by the operations teams.

    A cold start should be applied in very exceptional cases after contacting our support.

    A cold start might be required if something runs into an infinite loop and therefore floods the MQ tables with messages faster that the Engine Worker Processes can process them. Therefore a detailed analysis of the message queues is required before performing a cold start to gain a clear picture of the situation.

    A cold start is required after an initial data update (e.g. new major, minor, service pack or hotfix), in case Zero Downtime Upgrade is not used.



  • 8.  The COLD start 'HOT' topic

    Posted Sep 26, 2016 03:06 AM
    Thanks, guys. I have another Question related to this topic. If I find out that the MQWPs and MQCPs table are filled up. Is it safe to truncate all those tables when the system is still running ? If not, is there any affected to the running jobs/system ?


  • 9.  The COLD start 'HOT' topic

    Posted Sep 26, 2016 11:23 AM
    I would not recommend truncation on a running system - in essence, if you're truncating the MQ tables you're doing half a cold start (which isn't recommended). So, if you're at a point where you've isolated a loop or similar behavior filling MQ* tables, cold start. 

    The other big thing is with v11 a system in ZDU will then be forced to the latest with a cold start. Generally speaking, I'd go down the full list of other performance measures before a cold start. 


  • 10.  The COLD start 'HOT' topic

    Posted Sep 26, 2016 09:16 PM
    Thanks for your answer, Darren. But I guess if only 01 MQCP or 01 MQWP is filled up and the system is still up and running, we can truncate only this issued MQ table, isn't it ?


  • 11.  The COLD start 'HOT' topic

    Posted Sep 27, 2016 12:37 AM
    @Antoine Sauteron, Thanks for the useful article.


  • 12.  The COLD start 'HOT' topic

    Posted Sep 29, 2016 10:37 AM
    Duong_Nguyen-Nhat_2335
    Generally said, this is not recommended. Truncating even a single table can lead to worse problems than you had before. Not even a cold start truncates tables while the system is "running".
    A cold start is a drastic treatment, but truncating tables in a running system is way worse.


  • 13.  The COLD start 'HOT' topic

    Posted Sep 29, 2016 11:18 PM
    Daniel_Trimmel_2011 Thanks, I will note that. 


  • 14.  The COLD start 'HOT' topic

    Posted Dec 01, 2016 05:12 AM
    As far as I learned from a colleague following information could be usefull.

    Citation: "In summary it puts the automation processing in an inconsistent state which enforces manual intervention by the operations teams and creates additional load.

    A cold start should be applied in very exceptional cases and in alignment with Engineering only.
    A cold start might be required if something runs into an infinite loop and therefore floods the MQ tables with messages faster that the Engine Worker Processes can process them. Therefore a detailed analysis of the message queues is required before performing a cold start to gain a clear picture on the situation.
    A cold start is required after an initial data update (e.g. new major, minor, service pack or hotfix), in case of ZDU is not used."

    Many thanks to my colleague to let us know!



  • 15.  The COLD start 'HOT' topic

    Posted Dec 01, 2016 05:20 AM
    Muneer_Ali_8170 The SQL scripts for truncating the MQ Tables you requested we can not provide you via the community, they are different for DB Types and for all the Versions, since the MQ Tables have changed (some were added, some were removed some where changed...) Anyway, truncating the MQ only should be done in alignment with support, that means, therefore an incident on support side has to be created already. In case it is necessary, we will provide you for the specific case.

    A cold start should be applied in very exceptional cases after contacting our support.

    Just one more thing to add...

    This is basically right (of course) but, when performing an update of your Automation Engine and Initialdata, the coldstart is also crucial, in that case, and only in that case, you can do it also without contacting automic support ;)



  • 16.  The COLD start 'HOT' topic

    Posted Oct 10, 2017 07:56 AM
    Actually, if you are using ZDU to do an update (>= V11.2), you do not need to make a cold start.