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Re: radix tree implementation for quota ?
On Mon, Nov 29, 2010 at 11:12:21AM -0500, der Mouse wrote:
> Without any real data on what UID distribution looks like in practice,
> we're all speculating in a vacuum here.
Just for shits and giggles I ran this on a real password file with
about 350 users that's had lots of churn since it was first
established. Using Joerg's hash with a table of size 512 gave 90
collisions; using x % 509 (the nearest available prime) gave 91.
For comparison I tried some of the (more expensive) hashes from db4
and got 111, 94, and 84.
None of the hash functions generated significant hotspots. It seems
like a nonissue.
(Of course, hashing 350 things isn't exactly a big challenge...)
David A. Holland
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