Horton

Re: Patch: add timing of buffer I/O requests

Greg Stark <stark@mit.edu>

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From: Greg Stark <stark@mit.edu>
To: Robert Haas <robertmhaas@gmail.com>
Cc: "ktm@rice.edu" <ktm@rice.edu>, Peter Geoghegan <peter@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, Greg Smith <greg@2ndquadrant.com>, Magnus Hagander <magnus@hagander.net>, Ants Aasma <ants@cybertec.at>, pgsql-hackers@postgresql.org
Date: 2012-04-14T01:42:29Z
Lists: pgsql-hackers 
On Fri, Apr 13, 2012 at 8:15 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> That's probably true, but I'm not sure it's worth worrying about -
> one-in-four-billion is a pretty small probability.

Is this not subject to the birthday paradox? If you have a given hash
you're worried about a collision with then you have a
one-in-four-billion chance. But if you have a collection of hashes and
you're worried about any collisions then it only takes about 64k
before there's likely a collision.

-- 
greg