Index Advisor and MTI's. - IBM AS400

This is a discussion on Index Advisor and MTI's. - IBM AS400 ; Hi All, Possibly a stupid question or have miss-read overview of index advisor? If MTIís are created, after several indications that an index is required? Do you only get the benefit of creating a permanent index after an IPL? Trying ...

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Thread: Index Advisor and MTI's.

  1. Index Advisor and MTI's.

    Hi All,

    Possibly a stupid question or have miss-read overview of index
    advisor?

    If MTIís are created, after several indications that an index is
    required?


    Do you only get the benefit of creating a permanent index after
    an IPL?


    Trying deduce how much benefit there is taking the advice from
    index advisor.


    Any constructive input gratefully received.


    Believe that programmers should take into account efficiency
    when creating solutions.

    Kind Regards

    Ian

  2. Re: Index Advisor and MTI's.

    On Apr 20, 1:48*pm, Ian wrote:
    > Hi All,
    >
    > * * * Possibly a stupid question or have miss-read overview of index
    > advisor?
    >
    > * * * If MTIís are created, after several indications that an index is
    > required?
    >
    > * * * Do you only get the benefit of creating a permanent index after
    > an IPL?
    >
    > * * * Trying deduce how much benefit there is taking the advice from
    > index advisor.
    >
    > * * * Any constructive input gratefully received.
    >
    > * * * Believe that programmers should take into account efficiency
    > when creating solutions.
    >
    > Kind Regards
    >
    > Ian


    Index advisor in V5R4 is much improved. However, index advisor will
    suggest an index when that index should improve performance. That
    improvement might be 1% or it might be 90%. If you check the MTI's in
    Nvaigator, it tells you how often the index was used or suggested.
    That should give you an idea how useful it is. Since MTI's are
    deleted at IPL, an often-used MTI shpuld be built as an index.

    Experience will tell you a lot. Testing will tell you for sure.

  3. Re: Index Advisor and MTI's.

    Cheers Graybeard.

    Having to investigate dayend function, as doubling processors from two
    to four, made no difference.

    So I/O bound?

    Main storage not an issue I believe, as subsystems in calc mode.

    This appears to mean only way of improving is either new logical files
    or rewriting programs.

    Many of reporting functions use query or sql, so much fun to be had.

    Any tips and/or hints from those who have had similar opportunities
    gratefully accepted.

    Dealing with a package written by those not overly interested in
    efficiency! L

    Kind Regards

    Ian

    On Apr 21, 12:40 am, Graybeard wrote:
    > On Apr 20, 1:48 pm, Ian wrote:
    >
    >
    >
    > > Hi All,

    >
    > > Possibly a stupid question or have miss-read overview of index
    > > advisor?

    >
    > > If MTIís are created, after several indications that an index is
    > > required?

    >
    > > Do you only get the benefit of creating a permanent index after
    > > an IPL?

    >
    > > Trying deduce how much benefit there is taking the advice from
    > > index advisor.

    >
    > > Any constructive input gratefully received.

    >
    > > Believe that programmers should take into account efficiency
    > > when creating solutions.

    >
    > > Kind Regards

    >
    > > Ian

    >
    > Index advisor in V5R4 is much improved. However, index advisor will
    > suggest an index when that index should improve performance. That
    > improvement might be 1% or it might be 90%. If you check the MTI's in
    > Nvaigator, it tells you how often the index was used or suggested.
    > That should give you an idea how useful it is. Since MTI's are
    > deleted at IPL, an often-used MTI shpuld be built as an index.
    >
    > Experience will tell you a lot. Testing will tell you for sure.



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