Db2 for z/OS

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Unloading a PBG Tablespace

  • 1.  Unloading a PBG Tablespace

    Posted 22 days ago
    Hello,

    We have Db2 v12 for z/os at CATALOG LEVEL(V12R1M507) and CURRENT FUNCTION LEVEL(V12R1M505).

    We've been advising our DBAs to convert to PBG's when possible and one user raised a concern:

    Instead of unloads by partition, when you convert to PBG, the unload is in one file and it would be very large for the partitioned tablespaces. This is another perspective and not something that has been discussed with encouraging PBG.

    Can someone address this concern?

    Thanks.
    Gloria Fries

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    Gloria Fries
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  • 2.  RE: Unloading a PBG Tablespace

    Posted 21 days ago

    I see no problem. The recommended approach with PBGs these days is 32GB DSSIZE and MAXPARTITIONS 1 which is *exactly* the same maximum size as a simple or segmented tablespace.

    Now if you are going to DSSIZE 256GB and MAXPARTITIONS 256 that is a different number!!! But you cannot migrate from Partitioned to PBG anyways...

     

    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

     






  • 3.  RE: Unloading a PBG Tablespace

    Posted 20 days ago
    Thanks for the reply!

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    Gloria Fries
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  • 4.  RE: Unloading a PBG Tablespace

    Posted 20 days ago

    Whoops! Small typo: I meant DSSIZE 64 GB is equivalent to segmented and simple with their 2GB dataset size and 32 datasets (32 * 2GB = 64 GB)

     

     

    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: Unloading a PBG Tablespace

    Posted 20 days ago
    Hi Gloria,

    If the original tablespace was traditional (non-UTS) partitioned, it could easily be converted to PBR, and you could then unload by partition.  The conversion from non-UTS partitioned to PBG is much more invasive (unload, drop, create, load). 
    Robert Catterall published an excellent article about converting from non-UTS to UTS here:  http://robertsdb2blog.blogspot.com/2014/06/db2-for-zos-getting-to-universal-table.html

    Hope this helps,
    Steve

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    Steve Johnson
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  • 6.  RE: Unloading a PBG Tablespace

    Posted 20 days ago
    Without knowing all the details, IBM put in a tremendous amount of work, due to customer requests, to provide the ability to perform online conversions from "old" table spaces to UTS (PBR or PBG), so you wouldn't need to deal with unloads, capturing/restoring GRANTs, all those ugly things you don't like to deal with when dealing with conversion outages.  We did that almost exclusively on ours and it made our DBAs much happier not having to deal with unload/reloads on monstrous tables.

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    Greg DeBo
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