OutOfMemoryError in job commit / ParquetMetadataConverter

We're trying to write some 14B rows (about 3.6 TB in parquets) to parquet files. When our ETL job finishes, it throws this exception, and the status is "died in job commit".

2015-05-14 09:24:28,158 FATAL [CommitterEvent Processor #4] org.apache.hadoop.yarn.YarnUncaughtExceptionHandler: Thread Thread[CommitterEvent Processor #4,5,main] threw an Error. Shutting down now...
java.lang.OutOfMemoryError: GC overhead limit exceeded
at java.nio.ByteBuffer.wrap(ByteBuffer.java:373)
at java.nio.ByteBuffer.wrap(ByteBuffer.java:396)
at parquet.format.Statistics.setMin(Statistics.java:237)
at parquet.format.converter.ParquetMetadataConverter.toParquetStatistics(ParquetMetadataConverter.java:243)
at parquet.format.converter.ParquetMetadataConverter.addRowGroup(ParquetMetadataConverter.java:167)
at parquet.format.converter.ParquetMetadataConverter.toParquetMetadata(ParquetMetadataConverter.java:79)
at parquet.hadoop.ParquetFileWriter.serializeFooter(ParquetFileWriter.java:405)
at parquet.hadoop.ParquetFileWriter.writeMetadataFile(ParquetFileWriter.java:433)
at parquet.hadoop.ParquetFileWriter.writeMetadataFile(ParquetFileWriter.java:423)
at parquet.hadoop.ParquetOutputCommitter.writeMetaDataFile(ParquetOutputCommitter.java:58)
at parquet.hadoop.mapred.MapredParquetOutputCommitter.commitJob(MapredParquetOutputCommitter.java:43)
at org.apache.hadoop.mapred.OutputCommitter.commitJob(OutputCommitter.java:259)
at org.apache.hadoop.mapreduce.v2.app.commit.CommitterEventHandler$EventProcessor.handleJobCommit(CommitterEventHandler.java:253)
at org.apache.hadoop.mapreduce.v2.app.commit.CommitterEventHandler$EventProcessor.run(CommitterEventHandler.java:216)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

This seems to have something to do with the _metadata file creation, as the parquet files are perfectly fine and usable. Also I'm not sure how to alleviate this (i.e. add more heap space) since the crash is outside the Map/Reduce tasks themselves but seems in the job/application controller itself.

**Environment**: CentOS, MapR,. Scalding
**Reporter**: [hy5446](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=hy5446)

_{**Note**: *This issue was originally created as [PARQUET-282](https://issues.apache.org/jira/browse/PARQUET-282). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

parquet.hadoop.ParquetOutputCommitter.commitJob と ParquetFileWriter.writeMetadataFile から始め、次に ParquetMetadataConverter.toParquetMetadata と toParquetStatistics を追跡します。大量の row group で障害を再現し、生成された _metadata パスを調査します。job commit が報告された OutOfMemoryError なしで完了し、Parquet ファイルが引き続き使用可能であれば完了です。

索引モデルが issue の本文から書いたものです。