Re: killing processes

From: David Kerr <dmk(at)mr-paradox(dot)net>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Merlin Moncure <mmoncure(at)gmail(dot)com>, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>, pgsql-general(at)postgresql(dot)org
Subject: Re: killing processes
Date: 2009-07-21 17:47:04
Message-ID: 20090721174704.GD32936@mr-paradox.net
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On Tue, Jul 21, 2009 at 01:13:18PM -0400, Tom Lane wrote:
- David Kerr <dmk(at)mr-paradox(dot)net> writes:
- I tried it on a table with 899991 random values. It took frickin'
- forever, but seemed to be willing to respond to cancels anywhere
- along the line. I'm not sure why you're seeing differently.

Hehe, yeah. For me I let it run 10 min and hit ^C so maybe i just
hit it at a bad place.

- (The reason it takes forever is that numeric is a variable-width
- type, and access into a varwidth array is O(n), so the sorting
- step you've got here is O(n^2). It might help to use unnest()
- instead of this handmade version of it ...)

unnest() is 8.4 only, right?

I'm actually probably just going to install R and use the median
function from that. (I was hoping to avoid installing all of R)

Or maybe i'll try my hand at a perl one and see if that gives
ok performance.

Thanks!

Dave

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