A NullPointerException in DictionaryValuesWriter when writing Parquet

A NullReference Exception happens when writing a large partitioned Spark dataframe to Parquet.

The job is running in AWS EMR 5.8.0 (Spark 2.1.1).

Exception:

```
17/09/05 16:40:33 ERROR Utils: Aborting task
java.lang.NullPointerException
at org.apache.parquet.it.unimi.dsi.fastutil.objects.Object2IntLinkedOpenHashMap.getInt(Object2IntLinkedOpenHashMap.java:590)
at org.apache.parquet.column.values.dictionary.DictionaryValuesWriter$PlainFixedLenArrayDictionaryValuesWriter.writeBytes(DictionaryValuesWriter.java:307)
at org.apache.parquet.column.values.fallback.FallbackValuesWriter.writeBytes(FallbackValuesWriter.java:162)
at org.apache.parquet.column.impl.ColumnWriterV1.write(ColumnWriterV1.java:201)
at org.apache.parquet.io.MessageColumnIO$MessageColumnIORecordConsumer.addBinary(MessageColumnIO.java:467)
at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport$$anonfun$org$apache$spark$sql$execution$datasources$parquet$ParquetWriteSupport$$makeWriter$10.apply(ParquetWriteSupport.scala:184)
at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport$$anonfun$org$apache$spark$sql$execution$datasources$parquet$ParquetWriteSupport$$makeWriter$10.apply(ParquetWriteSupport.scala:172)
at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport$$anonfun$org$apache$spark$sql$execution$datasources$parquet$ParquetWriteSupport$$writeFields$1.apply$mcV$sp(ParquetWriteSupport.scala:124)
at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport.org$apache$spark$sql$execution$datasources$parquet$ParquetWriteSupport$$consumeField(ParquetWriteSupport.scala:437)
at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport.org$apache$spark$sql$execution$datasources$parquet$ParquetWriteSupport$$writeFields(ParquetWriteSupport.scala:123)
at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport$$anonfun$write$1.apply$mcV$sp(ParquetWriteSupport.scala:114)
at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport.consumeMessage(ParquetWriteSupport.scala:425)
at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport.write(ParquetWriteSupport.scala:113)
at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport.write(ParquetWriteSupport.scala:51)
at org.apache.parquet.hadoop.InternalParquetRecordWriter.write(InternalParquetRecordWriter.java:123)
at org.apache.parquet.hadoop.ParquetRecordWriter.write(ParquetRecordWriter.java:180)
at org.apache.parquet.hadoop.ParquetRecordWriter.write(ParquetRecordWriter.java:46)
at org.apache.spark.sql.execution.datasources.parquet.ParquetOutputWriter.write(ParquetOutputWriter.scala:40)
at org.apache.spark.sql.execution.datasources.FileFormatWriter$DynamicPartitionWriteTask$$anonfun$execute$2.apply(FileFormatWriter.scala:465)
at org.apache.spark.sql.execution.datasources.FileFormatWriter$DynamicPartitionWriteTask$$anonfun$execute$2.apply(FileFormatWriter.scala:440)
at scala.collection.Iterator$class.foreach(Iterator.scala:893)
at org.apache.spark.sql.catalyst.util.AbstractScalaRowIterator.foreach(AbstractScalaRowIterator.scala:26)
at org.apache.spark.sql.execution.datasources.FileFormatWriter$DynamicPartitionWriteTask.execute(FileFormatWriter.scala:440)
at org.apache.spark.sql.execution.datasources.FileFormatWriter$$anonfun$org$apache$spark$sql$execution$datasources$FileFormatWriter$$executeTask$3.apply(FileFormatWriter.scala:258)
at org.apache.spark.sql.execution.datasources.FileFormatWriter$$anonfun$org$apache$spark$sql$execution$datasources$FileFormatWriter$$executeTask$3.apply(FileFormatWriter.scala:256)
at org.apache.spark.util.Utils$.tryWithSafeFinallyAndFailureCallbacks(Utils.scala:1375)
at org.apache.spark.sql.execution.datasources.FileFormatWriter$.org$apache$spark$sql$execution$datasources$FileFormatWriter$$executeTask(FileFormatWriter.scala:261)
at org.apache.spark.sql.execution.datasources.FileFormatWriter$$anonfun$write$1$$anonfun$apply$mcV$sp$1.apply(FileFormatWriter.scala:191)
at org.apache.spark.sql.execution.datasources.FileFormatWriter$$anonfun$write$1$$anonfun$apply$mcV$sp$1.apply(FileFormatWriter.scala:190)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87)
at org.apache.spark.scheduler.Task.run(Task.scala:108)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:335)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)}}
```

**Reporter**: [Irina Truong](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=irinatruong)

_{**Note**: *This issue was originally created as [PARQUET-1089](https://issues.apache.org/jira/browse/PARQUET-1089). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Bắt đầu tại parquet-column/src/main/java/org/apache/parquet/column/values/dictionary/DictionaryValuesWriter.java, đặc biệt là đường dẫn writeBytes tại vị trí trong stack trace. Tái hiện lỗi bằng một Spark dataframe lớn đã được phân vùng, ghi vào Parquet với các phiên bản Spark và AWS EMR được báo cáo, sau đó truy vết tương tác với FallbackValuesWriter. Hoàn tất khi đã hiểu và ngăn chặn được NullPointerException, đồng thời có một regression test bao phủ trường hợp được báo cáo.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.