Re: Range types

From: Jeff Davis <pgsql(at)j-davis(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Greg Stark <gsstark(at)mit(dot)edu>, tomas(at)tuxteam(dot)de, Scott Bailey <artacus(at)comcast(dot)net>, hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Range types
Date: 2009-12-15 17:34:09
Message-ID: 1260898449.15987.1179.camel@jdavis
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On Tue, 2009-12-15 at 10:19 -0500, Tom Lane wrote:
> I'm not sure that anyone has argued that. I did suggest that there
> might be a small list of types for which we should provide discrete
> behavior (ie, with next/previous functions) and the rest could have
> continuous behavior (without that assumption). But I quite agree
> that we want both types of ranges.

It seems like we're moving toward treating TIMESTAMP as continuous.

If I'm correct, continuous ranges always need two extra bits of storage
for the exclusivity. But for timestamps, that means 16 bytes (2 x 8-byte
timestamp) turns into 17 bytes, which is really more like 20 or 24 bytes
with alignment.

Considering that these are likely to be used for audit or history
tables, 8 bytes of waste (50%) seems excessive -- especially when
treating them as discrete seems to work pretty well, at least for the
int64 timestamps.

Ideas?

Regards,
Jeff Davis

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