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https://issues.apache.org/jira/browse/SPARK-25175?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16593194#comment-16593194
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Chenxiao Mao commented on SPARK-25175:
--------------------------------------
[~dongjoon] [~yucai] Here is a brief summary. We can see that
* The data source tables always return a,B,c, no matter whether
spark.sql.caseSensitive is set to true or false and no matter metastore table
schema is in lower case or upper case. Since ORC file schema is (a,B,c,C),
** Is it better to return null in scenario 2 and 10?
** Is it better to return C in scenario 12?
** Is it better to fail due to ambiguity in scenario 15, 18, 21, 24, rather
than always return lower case one?
* The hive serde tables always throw IndexOutOfBoundsException at runtime.
* Since in case-sensitive mode analysis should fail if a column name in query
and metastore schema are in different cases, all AnalysisException(s) meet our
expectation.
Stacktrace of IndexOutOfBoundsException:
{code:java}
java.lang.IndexOutOfBoundsException: toIndex = 4
at java.util.ArrayList.subListRangeCheck(ArrayList.java:1004)
at java.util.ArrayList.subList(ArrayList.java:996)
at
org.apache.hadoop.hive.ql.io.orc.RecordReaderFactory.getSchemaOnRead(RecordReaderFactory.java:161)
at
org.apache.hadoop.hive.ql.io.orc.RecordReaderFactory.createTreeReader(RecordReaderFactory.java:66)
at
org.apache.hadoop.hive.ql.io.orc.RecordReaderImpl.<init>(RecordReaderImpl.java:202)
at
org.apache.hadoop.hive.ql.io.orc.ReaderImpl.rowsOptions(ReaderImpl.java:539)
at
org.apache.hadoop.hive.ql.io.orc.OrcRawRecordMerger$ReaderPair.<init>(OrcRawRecordMerger.java:183)
at
org.apache.hadoop.hive.ql.io.orc.OrcRawRecordMerger$OriginalReaderPair.<init>(OrcRawRecordMerger.java:226)
at
org.apache.hadoop.hive.ql.io.orc.OrcRawRecordMerger.<init>(OrcRawRecordMerger.java:437)
at
org.apache.hadoop.hive.ql.io.orc.OrcInputFormat.getReader(OrcInputFormat.java:1215)
at
org.apache.hadoop.hive.ql.io.orc.OrcInputFormat.getRecordReader(OrcInputFormat.java:1113)
at
org.apache.spark.rdd.HadoopRDD$$anon$1.liftedTree1$1(HadoopRDD.scala:257)
at org.apache.spark.rdd.HadoopRDD$$anon$1.<init>(HadoopRDD.scala:256)
at org.apache.spark.rdd.HadoopRDD.compute(HadoopRDD.scala:214)
at org.apache.spark.rdd.HadoopRDD.compute(HadoopRDD.scala:94)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87)
at org.apache.spark.scheduler.Task.run(Task.scala:109)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:345)
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:748)
{code}
> Case-insensitive field resolution when reading from ORC
> -------------------------------------------------------
>
> Key: SPARK-25175
> URL: https://issues.apache.org/jira/browse/SPARK-25175
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.3.1
> Reporter: Chenxiao Mao
> Priority: Major
>
> SPARK-25132 adds support for case-insensitive field resolution when reading
> from Parquet files. We found ORC files have similar issues. Since Spark has 2
> OrcFileFormat, we should add support for both.
> * Since SPARK-2883, Spark supports ORC inside sql/hive module with Hive
> dependency. This hive OrcFileFormat doesn't support case-insensitive field
> resolution at all.
> * SPARK-20682 adds a new ORC data source inside sql/core. This native
> OrcFileFormat supports case-insensitive field resolution, however it cannot
> handle duplicate fields.
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