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  • 1.  Catalog reorg while Db2 member is starting

    Posted Oct 27, 2021 10:11 AM
    We are scheduling Db2 catalog reorgs. If while these reorgs are running while a DB2 member is shutdown and started, would that be an issue?
    thanks
    Bill

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    williamgiannelliMe
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  • 2.  RE: Catalog reorg while Db2 member is starting

    Posted Oct 28, 2021 02:30 AM
    possibly, because (if memory serves) SYSLGRNX will be updated at each Db2 startup and shutdown.

    Also, when you COPY all the catalog objects before your REORG, your JCL needs to have a standalone QUIESCE for DSNDB01.SYSUTILX before all the other catalog tablespaces that will be quiesced (and of course you can'T include DSNDB06.SYSCOPY).

    Thanks.

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    Aurora


    Stay safe and healthy, y'all
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  • 3.  RE: Catalog reorg while Db2 member is starting

    Posted Oct 28, 2021 09:02 AM
    So in a datasharing group, if you are running Catalog reorgs on say member 1, you normally want members 2, 3, etc, down?

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    williamgiannelliMe
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  • 4.  RE: Catalog reorg while Db2 member is starting

    Posted Oct 28, 2021 09:14 AM
    No - But I would not start/stop members while reorging the Catalog/Directory as that is just asking for trouble!

    Roy Boxwell

    SOFTWARE ENGINEERING GmbH and SEGUS Inc.
    -Product Development-

    Vagedesstrasse 19
    40479 Dusseldorf/Germany
    Tel. +49 (0)211 96149-675
    Fax +49 (0)211 96149-32
    Email: R.Boxwell@seg.de
    Web http://www.seg.de
    Link zur Datenschutzerklärung

    Software Engineering GmbH
    Amtsgericht Düsseldorf, HRB 37894
    Geschäftsführung: Gerhard Schubert, Ulf Heinrich




  • 5.  RE: Catalog reorg while Db2 member is starting

    Posted Oct 28, 2021 09:17 AM

    Where's your sense of adventure, Roy?  Someone's got to prove a SHRLEVEL CHANGE Reorg of a Catalog object works absolutely fine when playing oingo boingo with the other members.  ��

     






  • 6.  RE: Catalog reorg while Db2 member is starting

    Posted Oct 28, 2021 11:34 AM
    I might be brave but *not* that brave! There is after all a very fine line between should - could - dead in the water.

    Roy Boxwell
    SOFTWARE ENGINEERING GmbH and SEGUS Inc.
    -Product Development-
    Vagedesstrasse 19
    40479 Dusseldorf/Germany
    Tel. +49 (0)211 96149-675
    Fax +49 (0)211 96149-32
    http://www.seg.de

    Software Engineering GmbH
    Amtsgericht Düsseldorf, HRB 37894
    Geschäftsführung: Gerhard Schubert, Ulf Heinrich 





  • 7.  RE: Catalog reorg while Db2 member is starting

    Posted Oct 28, 2021 12:39 PM
    Been laughing at "subsystem oingo-boingo" all morning. :) Maybe he should throw a CATMAINT in there too.

    William...the easy answer is, "don't schedule REORGs while subsystems are recycling". At a minimum...if you're doing SHRLEVEL CHANGE REORGs, plan your SWITCHTIMEs when the subsystems are "stable", either up or down. 

    For most of the catalog tables, you'd probably be fine to run a REORG on one subsystem while the others are in a state of flux, as long as you don't pull the subsystem that the REORG is running on. PROBABLY. 

    Most of the catalog tablespaces aren't updated during normal work. Those that carry package/plan data are only updated during BINDs. The ones with database definitions only during DDL. Stats tables only during a RUNSTATS.

    The biggest concern I'd have would be SYSLGRNX. As your subsystem shuts down, SYSLGRNX needs to write a record for all of the pagesets being closed, and then it'll need to be accessed again when Db2 starts up as each pageset is opened for write. If it's SHRLEVEL CHANGE you would probably...PROBABLY be okay, but if you hit the switch phase, you could encounter all kinds of errors.

    And then there's always the possibility that shutdown/restart doesn't go as-expected...in which case you may encounter issues with your REORGs or with restart that you didn't anticipate.

    Would really like more information on why you can't run the REORGs either immediately BEFORE or AFTER cycling subsystems. Just because you can, doesn't mean you should. My 0.02 is, don't chance it unless you have a darn good reason.

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    MarkWieczorkowski...
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  • 8.  RE: Catalog reorg while Db2 member is starting

    Posted Oct 28, 2021 12:51 PM
    We are a very small shop, so normally whenever I am doing systems work, I have the systems to myself and bring down the other members, just to be safe. The question was asked if "online migrations" are possible, why do the catalog - directory reorgs need "exclusive control". Again, I am not going to, in actual fact, have members recycled while running reorgs. But I wanted more specific detailed clarity on exactly what is happening during shut down and start up.
    I hope that makes more sense..........
    Thanks
    Bill


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    williamgiannelliMe
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  • 9.  RE: Catalog reorg while Db2 member is starting

    Posted Oct 28, 2021 09:20 AM
    hmmmm good question - probably, yes, because the logs will be updated and that's what the SYSLGRNX has in it, log information - but each member has its own logs so...

    obviously you could take THAT TBs out of your list and do it at the next outage - there's plenty of catalog tables that can be reorganised while Db2 is active/another member is starting...

    Sorry, just my 0.0000002c worth...


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    Aurora


    Stay safe and healthy, y'all
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