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From "Vijay (Updated) (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (CASSANDRA-3772) Evaluate Murmur3-based partitioner
Date Mon, 02 Apr 2012 02:16:29 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-3772?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Vijay updated CASSANDRA-3772:
-----------------------------

    Attachment: 0001-CASSANDRA-3772-Test.patch

micro benchmark shows a lot better performance

testing size of: 200000
Test MD5
MD5 test completed @ 1506
Test Murmur3
Murmur3 test completed @ 781

Hi Dave, while reviewing the patch it looks like 
Murmur3Partitioner.hash 

{code}
hashBytes[1] = (byte) (bufferLong >> 48);
...
{code}

is kind of redundant to 

{code}
case 15: k2 ^= ((long) key.get(offset+14)) << 48
... 
{code}

Though i dont think it is going to cause any additional latency :)


                
> Evaluate Murmur3-based partitioner
> ----------------------------------
>
>                 Key: CASSANDRA-3772
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-3772
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Core
>            Reporter: Jonathan Ellis
>            Assignee: Dave Brosius
>             Fix For: 1.2
>
>         Attachments: 0001-CASSANDRA-3772-Test.patch, MumPartitionerTest.docx, hashed_partitioner.diff,
hashed_partitioner_3.diff, try_murmur3.diff, try_murmur3_2.diff
>
>
> MD5 is a relatively heavyweight hash to use when we don't need cryptographic qualities,
just a good output distribution.  Let's see how much overhead we can save by using Murmur3
instead.

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