Re: sequential scans on few columns tables

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От Jim C. Nasby
Тема Re: sequential scans on few columns tables
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Msg-id 20030616224527.GM40542@flake.decibel.org
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Ответ на sequential scans on few columns tables  (Tomasz Myrta <jasiek@klaster.net>)
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On Mon, Jun 16, 2003 at 09:49:40PM +0200, Tomasz Myrta wrote:
> by denormalizing tables. Let's say we have table "users" which we split
> into 1:1 relation "users_header" and "users_data". We put searchable
> columns into users_header and rest of them into users_data. users_data
> have some integer foreign key referencing to users_header.
>
> What do you think about it? Does the Postgres use advantages of small
> table users_header? Sequential scan on memory cached table should speed
> up queries, the rest columns are in integer-indexed table which
> shouldn't slow it down.

Keep in mind that pgsql has a pretty heafty per-row overhead of 23
bytes. If your data table has a bunch of big varchars then it might be
worth it, otherwise it might not be.
--
Jim C. Nasby (aka Decibel!)                    jim@nasby.net
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