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https://issues.apache.org/jira/browse/CASSANDRA-2975?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13153858#comment-13153858
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David Allsopp commented on CASSANDRA-2975:
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Have just repeated the benchmark with HeapByteBuffer as input rather than
DirectByteBuffer (using ByteBuffer allocate() rather than allocateDirect()),
and the performance improvement seems to almost vanish.
The input to MurmurHash within Cassandra seems to be a HeapByteBuffer (based on
adding a println to the existing MurmurHash2 hash64() method), so the inlining
is probably of no benefit in practice.
> Upgrade MurmurHash to version 3
> -------------------------------
>
> Key: CASSANDRA-2975
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2975
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Brian Lindauer
> Assignee: Brian Lindauer
> Priority: Trivial
> Labels: lhf
> Fix For: 1.1
>
> Attachments:
> 0001-Convert-BloomFilter-to-use-MurmurHash-v3-instead-of-.patch,
> 0002-Backwards-compatibility-with-files-using-Murmur2-blo.patch,
> Murmur3Benchmark.java
>
>
> MurmurHash version 3 was finalized on June 3. It provides an enormous speedup
> and increased robustness over version 2, which is implemented in Cassandra.
> Information here:
> http://code.google.com/p/smhasher/
> The reference implementation is here:
> http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp?spec=svn136&r=136
> I have already done the work to port the (public domain) reference
> implementation to Java in the MurmurHash class and updated the BloomFilter
> class to use the new implementation:
> https://github.com/lindauer/cassandra/commit/cea6068a4a3e5d7d9509335394f9ef3350d37e93
> Apart from the faster hash time, the new version only requires one call to
> hash() rather than 2, since it returns 128 bits of hash instead of 64.
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