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Thread: dbspaces

  1. #1
    Join Date
    Aug 2003
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    2

    Post Unanswered: dbspaces

    I have created a fragmented table i.e table across two dbspaces.
    Now, I want to know how the rows have been scattered across two dbspaces, i.e number of rows in each dbspace for the table. Therefore please let me know the sql statement or set of actions to be done from dbaccess or any other informix utility for the same.

    Thanks in advance.

  2. #2
    Join Date
    Aug 2003
    Location
    Argentina
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    780

    Re: dbspaces

    Originally posted by shilpan
    I have created a fragmented table i.e table across two dbspaces.
    Now, I want to know how the rows have been scattered across two dbspaces, i.e number of rows in each dbspace for the table. Therefore please let me know the sql statement or set of actions to be done from dbaccess or any other informix utility for the same.

    Thanks in advance.
    Hi ShipaN,

    I think what You would rot with ALTER FRAGMENT ON TABLE xxxx INIT FRAGMENT BY ROUND ROBIN IN dbsp1, dbsp2....

    This scattered across two dbspaces.

    Now, to know the sql statment you must be capture the session running and to analyze them or to speak it with the developers of aplication.

    Gustavo.

  3. #3
    Join Date
    Jun 2003
    Location
    Hamburg, Germany
    Posts
    38

    Re: dbspaces

    Originally posted by shilpan
    I have created a fragmented table i.e table across two dbspaces.
    Now, I want to know how the rows have been scattered across two dbspaces, i.e number of rows in each dbspace for the table. Therefore please let me know the sql statement or set of actions to be done from dbaccess or any other informix utility for the same.

    Thanks in advance.
    Is the table fragmented by "round robin" or by "expression"? If it is done by expression, then a simple SQL (taken from your fragmentation expression) can give you the answer. If it is done by round robin, then pages are written in rotation (round-robin) between the fragments without regard to their content, so you should get an even (or very nearly even) spread of records across the fragments.

    If you're investigating a performance problem, then you also need to look at how the dbspaces are placed on your physical disks and what disk strategy you have, eg: RAID level. Sometimes, your RAID level and table fragmentation can interfere with each other and give bad performance.

  4. #4
    Join Date
    Aug 2003
    Location
    Argentina
    Posts
    780

    Re: dbspaces

    Originally posted by AdiHH
    Is the table fragmented by "round robin" or by "expression"? If it is done by expression, then a simple SQL (taken from your fragmentation expression) can give you the answer. If it is done by round robin, then pages are written in rotation (round-robin) between the fragments without regard to their content, so you should get an even (or very nearly even) spread of records across the fragments.

    If you're investigating a performance problem, then you also need to look at how the dbspaces are placed on your physical disks and what disk strategy you have, eg: RAID level. Sometimes, your RAID level and table fragmentation can interfere with each other and give bad performance.
    Hello,

    I am in agreement with which it thinks AdiHH, but if these experiencing problems of performace, then to several things to check.
    for example that value has OPTCOMPIND in file ONCONFIG? If it has 2
    (two), the exchange thing to 0 (zero), then onmode -ky, then oninit.
    And You have executed update statistics?

    Gustavo.

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