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From "Keith Turner (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ACCUMULO-4468) accumulo.core.data.Key.equals(Key, PartialKey) improvement
Date Thu, 22 Sep 2016 15:33:20 GMT

    [ https://issues.apache.org/jira/browse/ACCUMULO-4468?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15513616#comment-15513616
] 

Keith Turner commented on ACCUMULO-4468:
----------------------------------------

The network code uses the [Key.compress()|https://github.com/apache/accumulo/blob/1a663143c4d81367f7703bceb8b24374d59c154e/core/src/main/java/org/apache/accumulo/core/data/Key.java#L1085]
and [Key.decompress()|https://github.com/apache/accumulo/blob/1a663143c4d81367f7703bceb8b24374d59c154e/core/src/main/java/org/apache/accumulo/core/data/Key.java#L1137]
functions, maybe the test could use that to simulate what rfile does.  Its based on thrift
stuff though, so it would clunky to use.


> accumulo.core.data.Key.equals(Key, PartialKey) improvement
> ----------------------------------------------------------
>
>                 Key: ACCUMULO-4468
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-4468
>             Project: Accumulo
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 1.8.0
>            Reporter: Will Murnane
>            Priority: Trivial
>              Labels: newbie, performance
>         Attachments: benchmark.tar.gz, key_comparison.patch
>
>
> In the Key.equals(Key, PartialKey) overload, the current method compares starting at
the beginning of the key, and works its way toward the end. This functions correctly, of course,
but one of the typical uses of this method is to compare adjacent rows to break them into
larger chunks. For example, accumulo.core.iterators.Combiner repeatedly calls this method
with subsequent pairs of keys.
> I have a patch which reverses the comparison order. That is, if the method is called
with ROW_COLFAM_COLQUAL_COLVIS, it will compare visibility, cq, cf, and finally row. This
(marginally) improves the speed of comparisons in the relatively common case where only the
last part is changing, with less complex code.



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