Github user liancheng commented on a diff in the pull request:
https://github.com/apache/spark/pull/5298#discussion_r28241260
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/parquet/ParquetTableSupport.scala
---
@@ -98,12 +98,32 @@ private[parquet] class RowReadSupport extends
ReadSupport[Row] with Logging {
val metadata = new JHashMap[String, String]()
val requestedAttributes =
RowReadSupport.getRequestedSchema(configuration)
+ // convert fileSchema to attributes
+ val fileAttributes =
ParquetTypesConverter.convertToAttributes(fileSchema, true, true)
+ val fileAttMap = fileAttributes.map(f => f.name.toLowerCase ->
f.name).toMap
+
if (requestedAttributes != null) {
+ // reconcile names of requested Attributes
+ val modRequestedAttributes = requestedAttributes.map(attr => {
+ val lName = attr.name.toLowerCase
+ if (fileAttMap.contains(lName)) {
+ attr.withName(fileAttMap(lName))
+ } else {
+ if (attr.nullable) {
+ attr
+ } else {
+ // field is not nullable but not present in the parquet file
schema!!
+ // this is just a safety check since in hive all columns are
nullable
+ // throw exception here
+ throw new RuntimeException(s"""Field ${attr.name} is
non-nullable,
+ but not found in parquet file schema:
${fileSchema}""".stripMargin)
--- End diff --
This exception message would look pretty weird when printed since there
isn't a "margin" character (`|`) in the string. Also we don't want to split
this message into multiple lines. Maybe this:
```scala
throw new RuntimeException(
s"Field ${attr.name} is non-nullable, " +
s"but not found in parquet file schema: ${fileSchema}")
```
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