[infinispan-dev] MurmurHash fixes

[Mircea Markus]

On 13 Jan 2011, at 19:35, Manik Surtani wrote:

> Guys,
> 
> The MurmurHash2 impl we have in 4.2.0 is buggy in that my translation from the original C source was faulty and it effectively hashes over just 31 bits instead of 32.  It means the distribution result isn't as good as it could be.
> 
> Now it isn't that easy for me to just *fix* this in 4.2.1, since it means keys mapped to nodes using 4.2.0 may not map to the same node in 4.2.1.
> 
> So here is what I propose:
> 
> 1) Fix it in 4.2.x as MurmurHash2A
> 2) Use MurmurHash2A by default, *unless* a config flag is provided that forces the use of MurmurHash2.  (e.g., <hash function="MurmurHash2">)
> 
> This will even give us the ability to use MurmurHash3 in 5.0 when we have it.
> 
> WDYT?
+1. An production upgrade should not be affected by this change.
> 
> Cheers
> Manik
> --
> Manik Surtani
> manik at jboss.org
> twitter.com/maniksurtani
> 
> Lead, Infinispan
> http://www.infinispan.org
> 
> 
> 
> 
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