Re: Reducing data type space usage

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Gregory Stark <stark(at)enterprisedb(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Reducing data type space usage
Date: 2006-09-15 23:23:25
Message-ID: 200609152323.k8FNNPu29485@momjian.us
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Tom Lane wrote:
> Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > Tom Lane wrote:
> >> No, it'll be a 1-byte header with length indicating that no bytes
> >> follow,
>
> > Well, in my idea, 10000001 would be 0x01. I was going to use the
> > remaining 7 bits for the 7-bit ascii value.
>
> Huh? I thought you said 00000001 would be 0x01, that is, high bit
> clear means a single byte containing an ASCII character. You could
> reverse that but it just seems to make things harder --- the byte
> isn't a correct data byte by itself, as it would be with the other
> convention.

Oh, OK, I had high byte meaning no header, but clear is better, so
00000001 is 0x01, and 00000000 is "". But I see now that bytea does
store nulls, so yea, we would be better using 10000001, and it is the
same size as 00000000.

--
Bruce Momjian bruce(at)momjian(dot)us
EnterpriseDB http://www.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +

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