Re: How many fields in a table are too many

From: Jan Wieck <JanWieck(at)Yahoo(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, btober(at)seaworthysys(dot)com, scrawford(at)pinpointresearch(dot)com, kleptog(at)svana(dot)org, m_tessier(at)sympatico(dot)ca, pgsql-general(at)postgresql(dot)org
Subject: Re: How many fields in a table are too many
Date: 2003-06-28 15:05:51
Message-ID: 3EFDAECF.1010805@Yahoo.com
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Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)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
>
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