Github user maropu commented on a diff in the pull request:
https://github.com/apache/spark/pull/17758#discussion_r125267663
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSource.scala
---
@@ -468,7 +489,13 @@ case class DataSource(
throw new AnalysisException("Cannot save interval data type into
external storage.")
}
- providingClass.newInstance() match {
+ val resolvedRelation = providingClass.newInstance() match {
+ case relationToCheck: DataSourceValidator =>
--- End diff --
> In other cases, we need to ad-hoc check the duplication (e.g.,
JDBCRelation)
@cloud-fan How about this? Since we couldn't pass `df.schema` into the
check in `resolveRelation` you suggested, so I put the check here for write
paths. Actually, IMHO we need not have this datasource-specific check for read
paths because each datasource implementation should provide a valid schema when
inferring it in `FileFormat.inferSchema`, `JdbcUtils.getSchema`, ...
On the other hand, in write paths, I feel other datasource-specific checks
would be better to be done in `DataSource`. For example;
```
scala> spark.range(1).selectExpr("rand()").write.save("path")
org.apache.spark.sql.AnalysisException: Attribute name
"rand(1595701563628455153)" contains invalid character(s) among " ,;{}()\n\t=".
Please use alias to rename it.;
at
org.apache.spark.sql.execution.datasources.parquet.ParquetSchemaConverter$.checkConversionRequirement(ParquetSchemaConverter.scala:581)
at
org.apache.spark.sql.execution.datasources.parquet.ParquetSchemaConverter$.checkFieldName(ParquetSchemaConverter.scala:567)
at
org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport$$anonfun$setSchema$2.apply(ParquetWriteSupport.scala:446)
at
org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport$$anonfun$setSchema$2.apply(ParquetWriteSupport.scala:446)
at scala.collection.immutable.List.foreach(List.scala:381)
at
org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport$.setSchema(ParquetWriteSupport.scala:446)
at
org.apache.spark.sql.execution.datasources.parquet.ParquetFileFormat.prepareWrite(ParquetFileFormat.scala:112)
at
org.apache.spark.sql.execution.datasources.FileFormatWriter$.write(FileFormatWriter.scala:134)
```
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
