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R: R: space taken by a row & compressed data

From: "Leonardo Francalanci" <lfrancalanci(at)simtel(dot)ie>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: <pgsql-general(at)postgresql(dot)org>
Subject: R: R: space taken by a row & compressed data
Date: 2004-08-26 15:43:12
Message-ID: KNEFJLENOMMIGOKNCBFAMEHHEMAA.lfrancalanci@simtel.ie (view raw or flat)
Thread:
Lists: pgsql-general
> If you just stuck all the integers into a single integer-array column,
> it would be 1600 bytes wide, which is ... hmm ... not quite wide enough
> to trigger the toast logic.  Perhaps it would be worthwhile for you to
> run a custom build with TOAST_TUPLE_THRESHOLD/TOAST_TUPLE_TARGET set
> to half their standard values (see src/include/access/tuptoaster.h).

Could you point me to some docs on this TOAST-mechanism?
I only found http://postgresql.zadnik.org/projects/devel-toast.html
but seems very old.
For instance: what kind of method is used to compress data?

> You'd not need to write any specialized code that way.
Great!

> Note that if you sometimes search on the values of one of the non-index
> columns, this might be a bad idea.


No, this never happens.

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