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Re: Index usage when bitwise operator is used

From: valgog <valgog(at)gmail(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Index usage when bitwise operator is used
Date: 2007-09-18 10:36:23
Message-ID: 1190111783.077030.48670@22g2000hsm.googlegroups.com (view raw or flat)
Thread:
Lists: pgsql-performance
Hi Tom,

do you think it would be a good idea to ask GIN index team to
implement an int-based bitmap set indexing operator for GIN/GiST based
indexes? Or there will be a possibility to somehow optimally index
arrays of enumerations to implement such bitmap structures in 8.3 or
later postgresql versions?

With best regards,

-- Valentine

On Sep 17, 3:37 pm, t(dot)(dot)(dot)(at)sss(dot)pgh(dot)pa(dot)us (Tom Lane) wrote:
> "Kevin Grittner" <Kevin(dot)Gritt(dot)(dot)(dot)(at)wicourts(dot)gov> writes:
> > On Mon, Sep 17, 2007 at  2:49 AM, in message
> > <1190015368(dot)148293(dot)56(dot)(dot)(dot)(at)y42g2000hsy(dot)googlegroups(dot)com>, valgog
> > <val(dot)(dot)(dot)(at)gmail(dot)com> wrote:=20
> >> Are you sure you understood what was the question?
>
> >> Is the TBL1.CATEGORY = TBL2.CATEGORY the same as TBL1.CATEGORY &
> >> TBL2.CATEGORY > 0?
> > Yes, given that he stipulated that one and only one bit would be set.
>
> Really?  In that case, isn't this bit-field just a bad implementation of
> an enum-style field?
>
>                         regards, tom lane
>
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