Informix

nested-group-icon.png

DB2

Expand all | Collapse all

Storage Optimization Question

  • 1.  Storage Optimization Question

    Posted 30 days ago
    IDS 12.10.FC12
    Solaris 10 1/13

    Is doing a dbexport & dbimport of a database comparable to doing a repack, shrink, and defragment on every table?

    Thank you.

    David Grove

    ------------------------------
    David Grove
    ------------------------------


  • 2.  RE: Storage Optimization Question

    Posted 30 days ago
    If you did a defragment, then repack with shrink it might be close to a complete reload. How close depends on how fragmented the free space is in the dbspace(s) holding the tables.

    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.








  • 3.  RE: Storage Optimization Question

    Posted 30 days ago
    David:

    Very good question!  I would think yes but doing a dbexport and dbimport to defragment and shrink my customers' databases probably wouldn't go over to well with them.

    ------------------------------
    Best regards,
    Martin Graney
    Queues Enforth Development, Inc.
    Stoneham, MA 02148
    ------------------------------



  • 4.  RE: Storage Optimization Question

    Posted 30 days ago
    Yes ish - the dbimport should give  better results. Alter fragment into new-space should give you the same/similar results as the dbimport.

    Defrag/shrink will not move other table fragments out of way to give to contiguous space - remember windows defrag ?

    Cheers
    Paul

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





  • 5.  RE: Storage Optimization Question

    Posted 29 days ago
    Paul,

    Thank you for your comment.

    There remains a lot about Informix that I have not mastered.  Defrag/Repack/Shrink is certaiinly one of these areas.  I thought that "shrink" moved all the data to the "front" and left as much space as possible at the "end".  Or maybe that data movement is only within the extents that have already been allocated, and not general space management over the chunk as a whole??

    DG

    ------------------------------
    David Grove
    ------------------------------



  • 6.  RE: Storage Optimization Question

    Posted 29 days ago
    Thank you, Martin.

    Yes, it doesn't generate a log of enthusiasm among users to schedule downtime!

    DG

    ------------------------------
    David Grove
    ------------------------------