GitHub user maropu opened a pull request:
https://github.com/apache/spark/pull/16030
[SPARK-18108][SQL] Fix a bug to fail partition schema inference
## What changes were proposed in this pull request?
This pr is to fix a bug to fail partition schema inference;
```
scala> case class A(a: Long, b: Int)
scala> val as = Seq(A(1, 2))
scala> spark.createDataFrame(as).write.parquet("/data/a=1/")
scala> val df = spark.read.parquet("/data/")
scala> df.printSchema
root
|-- a: long (nullable = true)
|-- b: integer (nullable = true)
scala> df.collect
java.lang.NullPointerException
at
org.apache.spark.sql.execution.vectorized.OnHeapColumnVector.getLong(OnHeapColumnVector.java:283)
at
org.apache.spark.sql.execution.vectorized.ColumnarBatch$Row.getLong(ColumnarBatch.java:191)
at
org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificUnsafeProjection.apply(Unknown
Source)
at
org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificUnsafeProjection.apply(Unknown
Source)
at scala.collection.Iterator$$anon$11.next(Iterator.scala:409)
at scala.collection.Iterator$$anon$11.next(Iterator.scala:409)
```
This was because spark failed to infer the partition column as `LongType`
and it wrongly regarded the column as `IntegerType` in `DataSource`.
Therefore, the query failed in scanning the column from a parquet file.
## How was this patch tested?
Add tests in `ParquetPartitionDiscoverySuite`
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/maropu/spark SPARK-18108
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/16030.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #16030
----
commit 6bd8b4cdb63b20bc292a5ec1d8ca38281ee5bfbf
Author: Takeshi YAMAMURO <[email protected]>
Date: 2016-11-28T07:45:30Z
Fix a bug to fail partition schema inference
----
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