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https://issues.apache.org/jira/browse/HADOOP-449?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12566362#action_12566362
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chris.douglas edited comment on HADOOP-449 at 2/6/08 1:46 PM:
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* It looks like one can't meaningfully nest FilterInputFormats. A check in
initBaseInputFormat that rejects an attempt to do this would probably be a good
idea.
* IIRC, Configuration::IntegerRanges is limited to positive integers, so the
default range of (Integer.MIN_VALUE + "-" + Integer.MAX_VALUE) in
IntRangeFilter::setConf may be invalid.
* RangeFilter should probably accept a WritableComparator to support user types
and an alternative syntax for projections
* Would it be too constraining to limit SetFilter and ItemFilter to Text?
Filtering based on the string representation of Writables seems like an overly
general strategy.
The patch looks good; this should be very useful.
was (Author: chris.douglas):
* It looks like one can't meaningfully nest FilterInputFormats. A check in
initBaseInputFormat that rejects an attempt to do this would probably be a good
idea.
* IIRC, Configuration::IntegerRanges is limited to positive integers, so the
default range of (Integer.MIN_VALUE + "-" + Integer.MAX_VALUE) in
IntRangeFilter::setConf may be invalid.
* RangeFilter should probably accept a WritableComparator to support user types
and an alternative syntax for projections
* Would it be too constraining to limit SetFilter and ItemFilter to Text?
Filtering based on the string representation of Writables seems like an overly
general strategy.
The patch looks good; this should be very useful.
> 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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