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https://issues.apache.org/jira/browse/PIG-2462?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13184370#comment-13184370
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Alex Rovner commented on PIG-2462:
----------------------------------
Thanks Daniel for the info.
Some questions:
splitIndex within the PigInputFormat tracks the current PigSplit correct?
What does splitIndex within the PigSplit track? (From my understanding it
should track the current wrapped InputSplit)
There is also inputIndex within PigSplit. Wouldn't that track the InputSplit
index?
Finally, do we need to introduce an "idx" in PigSplit or my patch would suffice?
> getWrappedSplit is incorrectly returning the first split instead of the
> current split.
> --------------------------------------------------------------------------------------
>
> Key: PIG-2462
> URL: https://issues.apache.org/jira/browse/PIG-2462
> Project: Pig
> Issue Type: Bug
> Affects Versions: 0.9.1, 0.11
> Reporter: Alex Rovner
> Fix For: 0.11
>
> Attachments: splitsfix.patch
>
>
> If your loader needs information regarding what file is currently is being
> read (lets say for schema information), currently provides this ability by
> calling prepareToRead every time we read a new split. This is critical for
> ComibinedInputFormat as each mapper can read more then one file. In order for
> the load function to know what file we are currently reading, it should call
> getWrappedSplit() to get that information. How ever, getWrappedSplit always
> returns the first split in the list. Code from PigSplit.java:
> /**
> * This methods returns the actual InputSplit (as returned by the
> * {@link InputFormat}) which this class is wrapping.
> * @return the wrappedSplit
> */
> public InputSplit getWrappedSplit() {
> return wrappedSplits[0];
> }
> Furthermore, in PigRecordReader.java the splitIndex is never incremented when
> changing from split to split. So in fact, even if getWrappedSplit() wold be
> changed to return wrappedSplits[splitIndex]; it would still return the
> incorrect index.
> This can be fixed by changing PigRecordReader to increment
> PigSplit.splitIndex everytime the split chagnes in the following code:
> /**
> * Get the record reader for the next chunk in this CombineFileSplit.
> */
> protected boolean initNextRecordReader() throws IOException,
> InterruptedException {
> if (curReader != null) {
> curReader.close();
> curReader = null;
> if (idx > 0) {
> progress += pigSplit.getLength(idx-1); // done processing
> so far
> }
> }
> // if all chunks have been processed, nothing more to do.
> if (idx == pigSplit.getNumPaths()) {
> return false;
> }
> // get a record reader for the idx-th chunk
> try {
>
> curReader =
> inputformat.createRecordReader(pigSplit.getWrappedSplit(idx), context);
> LOG.info("Current split being processed
> "+pigSplit.getWrappedSplit(idx));
> if (idx > 0) {
> // initialize() for the first RecordReader will be called by
> MapTask;
> // we're responsible for initializing subsequent
> RecordReaders.
> curReader.initialize(pigSplit.getWrappedSplit(idx), context);
> pigSplit.get
> loadfunc.prepareToRead(curReader, pigSplit);
> }
> } catch (Exception e) {
> throw new RuntimeException (e);
> }
> idx++;
> return true;
> }
> }
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