Re: How many fields in a table are too many

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От Bruce Momjian
Тема Re: How many fields in a table are too many
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Msg-id 200306281738.h5SHcQP05772@candle.pha.pa.us
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Ответ на Re: How many fields in a table are too many  (Jan Wieck <JanWieck@Yahoo.com>)
Ответы Re: How many fields in a table are too many  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-general
Is this a TODO?

    When columns can be reordered, move varlena columns to the end?


---------------------------------------------------------------------------

Jan Wieck wrote:
> Tom Lane wrote:
> > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >> Is the issue of many columns in a tuple the same issue as a SELECT
> >> having many columns?
> >
> > I believe all the same inefficiencies need to be fixed whichever
> > way you look at it.  Probably "many columns in SELECT" is the more
> > accurate description though.
>
> Together with the recent discussions about attribute reordering, it'd
> make sense, if we have a "resentation order" different from the actual
> physical tuple layout, that the table starts with all variable length
> fields at the end. This would give a better utilization of attribute
> offset caching.
>
> Don't know though, if this counts for much of the suffering.
>
>
> Jan
>
> >
> >             regards, tom lane
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 6: Have you searched our list archives?
> >
> >                http://archives.postgresql.org
>
>
>
> --
> #======================================================================#
> # It's easier to get forgiveness for being wrong than for being right. #
> # Let's break this rule - forgive me.                                  #
> #================================================== JanWieck@Yahoo.com #
>
>

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