Re: Time-correlated columns in large tables

From: "Luke Lonergan" <llonergan(at)greenplum(dot)com>
To: "Jeroen T(dot) Vermeulen" <jtv(at)xs4all(dot)nl>, "Heikki Linnakangas" <heikki(at)enterprisedb(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Time-correlated columns in large tables
Date: 2007-03-07 16:06:05
Message-ID: C2144D1D.28B91%llonergan@greenplum.com
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Jeroen,

On 3/5/07 12:39 PM, "Jeroen T. Vermeulen" <jtv(at)xs4all(dot)nl> wrote:

> I guess if you did simple run-length compression on these bitmaps you'd
> end up more or less where I came in. But you wouldn't want to flip a bit
> somewhere in the middle of a compressed data stream, of course. :-

We handle that by doing a recompression in page if possibly, page splitting
if not.

Jie/Gavin's work will initially be an equality encoded bitmap as Heikki
indicates, soon after we can implement range encoding, etc.

- Luke

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