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  1. #1
    Join Date
    Feb 2010
    Posts
    1

    Unanswered: two keys in a regular index

    Hi!

    When I create an Index with 2 collumns as key-values, what kind of index does db2 create?

    example:
    table schema is tab1{[a: integer, b: char(10)]}

    index creation:

    create index index1 on tab1 (a asc, b asc);

    i don't use any clustering indexes, and

    select indextype from syscat.indexes where indname='index1'

    gives me "REG", so it's not a dimensional block index.

    Therefore it must be a kind of B+ -tree, but how are 2 keys organized in a B+-Tree? are they somehow merged to one keyvalue?

    Types of index access
    seems to imply that one level of the b+-tree filled with key a -values and the next level with key b-values, but I couldn't find a clear statement on this.

    a link pointing to an answer would be nice. thanks in advance.

  2. #2
    Join Date
    Jun 2003
    Location
    Toronto, Canada
    Posts
    5,516
    Provided Answers: 1
    Index key is a concatenation of values that make it up. Check the PDF Performance Guide for more details.
    ---
    "It does not work" is not a valid problem statement.

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