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https://issues.apache.org/jira/browse/CRUNCH-368?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13943867#comment-13943867
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Chao Shi commented on CRUNCH-368:
---------------------------------
Before this patch, no WritableComparator is registered, so a default
implementation will be used, which is deserializing both keys and compare the
objects. The registered comparator acts as a kind of optimization. You can see
examples in Text/Text.Comparator or IntWritable/IntWritable.Comparator.
> TupleWritable.Comparator
> ------------------------
>
> Key: CRUNCH-368
> URL: https://issues.apache.org/jira/browse/CRUNCH-368
> Project: Crunch
> Issue Type: Improvement
> Components: Core
> Affects Versions: 0.8.3
> Reporter: Chao Shi
> Assignee: Chao Shi
> Attachments: crunch-368.patch
>
>
> This patch should improve comparison performance on TupleWritables. It saves
> the deserialization overhead. It is particularly useful when the input tuple
> are large, e.g. contains long strings.
> Please note that this changes the binary format of TupleWritable. It adds a
> var-int indicating size of field after each type code. This is a limitation
> of the writable system. We do not know the size of each field until fully
> desalinizing it.
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