Re: Group-count estimation statistics

From: Greg Stark <gsstark(at)mit(dot)edu>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Group-count estimation statistics
Date: 2005-01-29 07:17:45
Message-ID: 87acqsu2jq.fsf@stark.xeocode.com
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Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Greg Stark's thought about a power correction seemed interesting too, though
> again far too optimistic to trust without some good math to back it up.

Fwiw, I'm pretty sure good math is not going to back up my off-the-cuff
algorithm. But I did like the answer it gave in this instance.

I'm told an actual solution to the problem is hard and probably not even
solvable in closed form. I'm still looking around but I suspect we would need
some pretty severe simplifying assumptions to make it work.

--
greg

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