From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com> |
Cc: | Greg Stark <gsstark(at)mit(dot)edu>, Neil Conway <neilc(at)samurai(dot)com>, "Hans-J?rgen Sch?nig" <postgres(at)cybertec(dot)at>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: DISTINCT vs. GROUP BY |
Date: | 2005-09-20 22:45:07 |
Message-ID: | 200509202245.j8KMj7Z19667@candle.pha.pa.us |
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Lists: | pgsql-hackers |
Jim C. Nasby wrote:
> > What do these URL's have that the current TODO does not?
> >
> > * Consider using hash buckets to do DISTINCT, rather than sorting
> >
> > This would be beneficial when there are few distinct values. This is
> > already used by GROUP BY.
>
> Maybe it's just me, but the recent run-through of the TODO list
> indicated that there's a fair number of items that people look at and
> don't really knowh what they mean. Providing the context (ie: email
> thread) that spawned an idea seems extremely valuable in being able to
> explain the idea behind a TODO item. They also usually contain valuable
> tips about how a TODO could be implemented. In this example, having
> quick reference to the discussion about hashagg and first()/last() would
> probably prove useful.
True, but sometimes the thread winds all around and there isn't a
definative explaination of how to go at something. I woul rather digest
the information to improve it, rather than require people to wade around
in an email thread. Is there some detail the TODO is missing?
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073
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