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https://issues.apache.org/jira/browse/PIG-2462?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13183276#comment-13183276
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Alex Rovner commented on PIG-2462:
----------------------------------
Daniel -- there is no member idx in PigSplit.java. The index thats supposed to
be tracked is splitIndex. Furthermore with combined input format,
PigRecordReader does not increment the value of splitIndex when switching the
reading from one split to the next even though it does increment and uses this
index internally. Therefore if we just change wrappedSplits[0] to
wrappedSplits[splitIndex] you will still have this issue. I have verified that
splitIndex is not modified anywhere except through the constructor in
PigSplit.java.
I have made the needed code changes and have verified them with my loader. Now
my log messages from my loader correspond to the log messages from
PigRecordReader (originally that was not the case).
> 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
> Reporter: Alex Rovner
> Fix For: 0.9.1, 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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