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https://issues.apache.org/jira/browse/LUCENE-5604?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13967884#comment-13967884
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Dawid Weiss commented on LUCENE-5604:
-------------------------------------

> by setting a common static seed on JVM init (just System.currentTimeMillis()).

This will render any tests that rely on hash ordering, etc. not-repeatable. I 
suggest initializing this to current time millis OR to the current random seed 
value (system property 'tests.seed').

> Should we switch BytesRefHash to MurmurHash3?
> ---------------------------------------------
>
>                 Key: LUCENE-5604
>                 URL: https://issues.apache.org/jira/browse/LUCENE-5604
>             Project: Lucene - Core
>          Issue Type: Improvement
>          Components: core/index
>            Reporter: Michael McCandless
>            Assignee: Michael McCandless
>             Fix For: 4.9, 5.0
>
>         Attachments: BytesRefHash.perturb.patch, LUCENE-5604.patch
>
>
> MurmurHash3 has better hashing distribution than the current hash function we 
> use for BytesRefHash which is a simple multiplicative function with 31 
> multiplier (same as Java's String.hashCode, but applied to bytes not chars).  
> Maybe we should switch ...



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