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https://issues.apache.org/jira/browse/HADOOP-449?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12567850#action_12567850
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Owen O'Malley commented on HADOOP-449:
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I agree with Chris. Using obj1.toString().equals(obj2.toString()) is both very
expensive and likely to break. We got 2x speedups out of TextOutputFormat by
avoiding a obj.toString().toBytes("UTF-8") data conversion pair. I'd be very
worried about the performance if you are doing toString for compares.
> Generalize the SequenceFileInputFilter to apply to any InputFormat
> ------------------------------------------------------------------
>
> Key: HADOOP-449
> URL: https://issues.apache.org/jira/browse/HADOOP-449
> Project: Hadoop Core
> Issue Type: Improvement
> Components: mapred
> Affects Versions: 0.17.0
> Reporter: Owen O'Malley
> Assignee: Enis Soztutar
> Fix For: 0.17.0
>
> Attachments: filterinputformat_v1.patch
>
>
> I'd like to generalize the SequenceFileInputFormat that was introduced in
> HADOOP-412 so that it can be applied to any InputFormat. To do this, I
> propose:
> interface WritableFilter {
> boolean accept(Writable item);
> }
> class FilterInputFormat implements InputFormat {
> ...
> }
> FilterInputFormat would look in the JobConf for:
> mapred.input.filter.source = the underlying input format
> mapred.input.filter.filters = a list of class names that implement
> WritableFilter
> The FilterInputFormat will work like the current SequenceFilter, but use an
> internal RecordReader rather than the SequenceFile. This will require adding
> a next(key) and getCurrentValue(value) to the RecordReader interface, but
> that will be addressed in a different issue.
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