Title: RE: what's hash-join

Hi Kevin,

It's quick if you have the temp space to support it.  however with larger tables my experience has been that it blows temp, isn't that much faster even if you do have the temp space, and in most cases you are better off with index-driven nested loops join.  It works well with small to medium-sized tables.

Just my .02

List, if I'm wrong, please correct me.

Lisa Koivu
Oracle Database Administrator
954-935-4117

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    -----Original Message-----
    From:   Kevin Kostyszyn [SMTP:[EMAIL PROTECTED]]
    Sent:   Thursday, May 31, 2001 9:34 AM
    To:     Multiple recipients of list ORACLE-L
    Subject:        RE: what's hash-join

    What's the performance (gain/loss) on such a join, when would you want to
    use one?
    Kev

    -----Original Message-----
    McDonald
    Sent: Thursday, May 31, 2001 6:00 AM
    To: Multiple recipients of list ORACLE-L


    A method of joining two tables.  You scan each and use
    a hashing algorithm to isolate/match keys.

    hth
    connor

    --- Senthil Ganapathi
    <[EMAIL PROTECTED]> wrote: >
    > Hi Rukmini
    > could tell me what's that hash-join
    >
    > GSK
    >
    >
    >
    >
    >                     "Rukmini
    >
    >                     Devi"                To:
    > Multiple recipients of list ORACLE-L
    >                     <rukmini@indb
    > <[EMAIL PROTECTED]>
    >                     rain.com>            cc:
    >
    >                     Sent by:             Subject:
    >  Re: 4 join methods?
    >                     root@fatcity.
    >
    >                     com
    >
    >
    >
    >
    >
    >                     31-05-01
    >
    >                     09:55 AM
    >
    >                     Please
    >
    >                     respond to
    >
    >                     ORACLE-L
    >
    >
    >
    >
    >
    >
    >
    >
    >
    > 1. Equi-join     2. Self-join     3. Outer-join  4.
    > Hash-join
    >
    > rukmini
    > ----- Original Message -----
    > To: "Multiple recipients of list ORACLE-L"
    > <[EMAIL PROTECTED]>
    > Sent: Thursday, May 31, 2001 11:20 AM
    >
    >
    > > i feel the fourth one is self join.
    > >
    > > ----- Original Message -----
    > > To: Multiple recipients of list ORACLE-L
    > <[EMAIL PROTECTED]>
    > > Sent: Thursday, May 31, 2001 8:10 AM
    > >
    > >
    > > > Hi,
    > > >
    > > > I just read there are four join methods.  I know
    > three:
    > > >
    > > > Nested loops
    > > > Sort merge
    > > > Hash join
    > > >
    > > > What's the fourth?
    > > >
    > > > - Greg
    > > >
    > > > --
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