D3 and mvBase

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  • 1.  D3 - trying to determine when a group lock is set instead of an item lock

    Posted 08-11-2022 15:44
    Just started a position at Houston's Inc which uses D3. Apparently, sometimes they are setting group locks and other times they set item locks. However, no one seems to know why it does one over the other. The D3 handbook is unclear. We are trying to remove the group locks from happening as they really should only be item locks within their applications. 

    The manual states that the typical readu, matreadu, etc create the locks. But there is no info on how a group is created vs the item...or perhaps both are created at the same time, but the group lock is released sooner? 

    Looking for a way to identify when the code is generating a group lock instead of an item lock so that we can switch to item locks only.

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    Chris Razzano
    Senior PICK programmer
    Rocket Forum Shared Account
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  • 2.  RE: D3 - trying to determine when a group lock is set instead of an item lock

    ROCKETEER
    Posted 08-11-2022 18:28
    You don't set group locks - we do. You set item locks with READU et al.

    What happens is that group locks are set momentarily when a group is accessed by anything doing reads or writes, including file-saves, selects, all manner of group reads ( lock type RDO ). Also any writes will temporarily set a group lock ( lock type UPD ). So unless you get a persistent group lock, don't worry. If you DO get a persistent group lock, look at the PIB that's holding it and see what it's doing  ( WHERE <pib> LZ ). If it's in lock-fail, you'll need to chase it down. The most common persistent group locks are the ones set by the file-save on MDS and each account's MD, especially on accounts with a large number of files and/or files with a lot of data in them.

    Hope this helps.​

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    Brian S. Cram
    Principal Technical Support Engineer
    Rocket Software
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  • 3.  RE: D3 - trying to determine when a group lock is set instead of an item lock

    Posted 08-12-2022 07:07
    Hi guys, not sure If this helps but in my "days" with AIX and a 2K frame size group it was sometimes an idea to force the file to span groups such that a group lock would not occur. Play around with file extents (make them smaller) and see whether this helps.

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    Stefano Gallotta
    Managing Member
    Simply Red Open Systems
    Milnerton ZA
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  • 4.  RE: D3 - trying to determine when a group lock is set instead of an item lock

    ROCKETEER
    Posted 08-12-2022 10:07
    Stefano, you mean like make the modulo bigger so the groups are smaller? Hmmm. Good idea. But I think the posted question was a curiosity and not an indication of a true problem. Just "Q: How do I set a group lock? A: You don't".

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    Brian S. Cram
    Principal Technical Support Engineer
    Rocket Software
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  • 5.  RE: D3 - trying to determine when a group lock is set instead of an item lock

    Posted 08-12-2022 10:18
    Edited by Chris Razzano 08-12-2022 10:18
    No, it is an actual problem. Due to the group locks occurring, users are unable to access records that were not the target of the lock by another port.

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    Chris Razzano
    Senior PICK programmer
    Rocket Forum Shared Account
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  • 6.  RE: D3 - trying to determine when a group lock is set instead of an item lock

    ROCKETEER
    Posted 08-12-2022 10:23
    Time to open a support case. Please do a WHICH CAD from TCL and copy/paste that into an email with a brief description of the problem to support@rocketsoftware.com and we'll get in and take a look.

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    Brian S. Cram
    Principal Technical Support Engineer
    Rocket Software
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  • 7.  RE: D3 - trying to determine when a group lock is set instead of an item lock

    ROCKETEER
    Posted 08-12-2022 10:43
    Would you please email me your direct phone number to bcram@rocketsoftware.com? I'd like to give you a call and get this sorted out.

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    Brian S. Cram
    Principal Technical Support Engineer
    Rocket Software
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