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  • 1.  Quickie question: Release 12.10: What is max size of physical log?

    Posted 19 days ago

    Greetings.

    On a new Linux box, I created a 4GB DBspace named phnysdbs. The name kinds tells you what I had in mind for it.  I tried to move it out of te root DBspace into its new apartment with this command:

    onparams -p -s 4194300 -d physdbs  # This is a few K shy of 4GB. 

    I get the message:  Physical log size specified is too large.

    I am guessing the max size in indeed 2GB.  I could mess around and try to find some other max value but I'd rather hear it from the experts.

    WOW! less than 5000 words!   record for me!  😇

    Thanks for quickie answers.



    ------------------------------
    +-----------------------------------------------------------+
    | I am pleased to report that I had no problems today. |
    | I had only issues, opportunities, challenges and valuable |
    | learning experiences. |
    +------------------------------------------ Jacob S --------+
    ------------------------------


  • 2.  RE: Quickie question: Release 12.10: What is max size of physical log?

    Posted 19 days ago

    Try reducing the size a bit more.  I don't think that you have left enough room for the overhead needed for the space.



    ------------------------------
    Mike Walker
    xDB Systems, Inc
    www.xdbsystems.com
    ------------------------------



  • 3.  RE: Quickie question: Release 12.10: What is max size of physical log?

    Posted 19 days ago
    No path ????


    Cheers
    Paul

    Paul Watson
    Oninit LLC
    +1-913-387-7529
    www.oninit.com
    Oninit®️ is a registered trademark of Oninit LLC





  • 4.  RE: Quickie question: Release 12.10: What is max size of physical log?
    Best Answer

    Posted 19 days ago
    My bad - misread 

    how big is the actual dbspace ? Did you allow for the header ??

    Cheers
    Paul

    Paul Watson
    Oninit LLC
    +1-913-387-7529
    www.oninit.com
    Oninit®️ is a registered trademark of Oninit LLC

    On May 25, 2026, at 17:07, Paul Watson <paul@oninit.com> wrote:

    No path ????


    Cheers
    Paul

    Paul Watson
    Oninit LLC
    +1-913-387-7529
    www.oninit.com
    Oninit®️ is a registered trademark of Oninit LLC





  • 5.  RE: Quickie question: Release 12.10: What is max size of physical log?

    Posted 19 days ago

    Thanks, Paul & Mike.

    Since I have never tried to fill a DBspace with the physical log, I would have assumed that the header is included in the size of the log.  So I was wrong.

    Adjustment:

    onparams -p -s 4194000 -d physdbs

    That worked just fine: 

    Physical Logging
    Buffer bufused  bufsize  numpages   numwrits   pages/io
      P-2  2        125      22781      3017       7.55
          phybegin         physize    phypos     phyused    %used
          2:53             2097000    0          2          0.00

    That's all I needed.

    Gracias! Спасибо! Köszönöm szépen. (and in some other languages I don't speak..)



    ------------------------------
    +-----------------------------------------------------------+
    | I am pleased to report that I had no problems today. |
    | I had only issues, opportunities, challenges and valuable |
    | learning experiences. |
    +------------------------------------------ Jacob S --------+
    ------------------------------

    Original Message


  • 6.  RE: Quickie question: Release 12.10: What is max size of physical log?

    Posted 19 days ago

    There's always the option of creating a Plogspace, it will use all available free pages in the chunk as the size of physical log.

    https://www.ibm.com/docs/en/informix-servers/12.10.0?topic=utility-onspaces-c-p-create-plogspace

    Example :
    Dbspaces
    address          number   flags      fchunk   nchunks  pgsize   flags    owner    name
    484b6c20         7        0x1030001  7        1        2048     N PBA    informix physdbs

    Chunks
    address          chunk/dbs     offset     size       free       bpages     flags pathname
    48160028         7      7      0          51200      0                     PO-BED physdbs

    DBspace Usage Report: physdbs             Owner: informix  Created: 05/26/2026


     Chunk Pathname                             Pagesize(k)  Size(p)  Used(p)  Free(p)
         7 physdbs                                        2    51200    51200        0

     Description                                                   Offset(p)  Size(p)
     ------------------------------------------------------------- -------- --------
     RESERVED PAGES                                                       0        2
     CHUNK FREELIST PAGE                                                  2        1
     physdbs:'informix'.TBLSpace                                          3       50
     PHYSICAL LOG                                                        53    51147

     Total Used:    51200
     Total Free:        0



    ------------------------------
    Casey Tan
    ------------------------------

    Original Message


  • 7.  RE: Quickie question: Release 12.10: What is max size of physical log?

    Posted 19 days ago

    Hello Jacob,

    try onstat -g cfg full PHYSFILE to get the min/max values.
    The min Value is 200 and the max value is 2^31-1 kbyte (or 2TB-1kbyte).

    Cheers,
    Markus



    ------------------------------
    Markus Holzbauer
    ------------------------------



  • 8.  RE: Quickie question: Release 12.10: What is max size of physical log?

    Posted 18 days ago
    Jacob: 
    It's not overhead of the physlog that you needed to leave space for. Rather for the reserved pages at the head of the dbspace.

    Art


    Art S. Kagel, President and Principal Consultant
    ASK Database Management


    Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference.  Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves.








    Original Message


  • 9.  RE: Quickie question: Release 12.10: What is max size of physical log?

    Posted 18 days ago

    Hi,

    I think you must have continues size in this space at least: (-s <size> (-53 pages)).

    Regards,



    ------------------------------
    Boycho Velkov
    ------------------------------



  • 10.  RE: Quickie question: Release 12.10: What is max size of physical log?

    Posted 18 days ago

    Before performing such a move to a new dbspace to store your physical log:

    1/ Determine whether adequate contiguous space in the target chunk is available by running the oncheck -pe command before making the physical log move using onparams.

    The space that is allocated for the physical log must be contiguous. When you change the physical log size or location, if the target dbspace does not contain adequate contiguous space, the server does not change the physical log. 

    2/ If you move the log to a dbspace without adequate contiguous space or increase the log size beyond the available contiguous space, the operation will fail and the physical log will not change.

    3/ Do not forget that you have to take into consideration the 53 header pages (2 reserved pages, 1 chunk free list page and 50 pages for the tablespaces management) since it is the first chunk of your new dbspace where you are moving the physical log to; you did not have to worry about the 53 pages in the rootdbs since you already had 12 reserved pages (rootdbs specific: being the instance kernel) + 1 chunk free lost page + 50 pages for the tablespace management + other information (sysdadmin database, initial logical logs before moving them out, other information ...). Basically you did not have to worry about the 53 pages in the rootdbs where you have to take into consideration these pages in the new dbspace for your physical log.


    Cordialement, Regards,    Khaled Bentebal  Mobile: 33 (0) 6 07 78 41 97 Email: khaled.bentebal@consult-ix.fr Site Web:  www.consult-ix.fr
    Le 25/05/2026 à 23:48, Jacob Salomon via IBM Community a écrit :
    0100019e611ca2d7-a78b2f6c-8de1-42d7-8e90-47a36b585b33-000000@email.amazonses.com">
    Greetings. On a new Linux box, I created a 4GB DBspace named phnysdbs. The name kinds tells you what I had in mind for it. I tried to move it... -posted to the "Informix" group





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