From 7374e518e2641fddfe57003340db410224b37581 Mon Sep 17 00:00:00 2001
From: gatorsmile <gatorsmile@gmail.com>
Date: Sat, 9 Jul 2016 20:35:45 +0800
Subject: [PATCH] [SPARK-16401][SQL] Data Source API: Enable Extending
RelationProvider and CreatableRelationProvider without Extending
SchemaRelationProvider
#### What changes were proposed in this pull request?
When users try to implement a data source API with extending only `RelationProvider` and `CreatableRelationProvider`, they will hit an error when resolving the relation.
```Scala
spark.read
.format("org.apache.spark.sql.test.DefaultSourceWithoutUserSpecifiedSchema")
.load()
.write.
format("org.apache.spark.sql.test.DefaultSourceWithoutUserSpecifiedSchema")
.save()
```
The error they hit is like
```
org.apache.spark.sql.test.DefaultSourceWithoutUserSpecifiedSchema does not allow user-specified schemas.;
org.apache.spark.sql.AnalysisException: org.apache.spark.sql.test.DefaultSourceWithoutUserSpecifiedSchema does not allow user-specified schemas.;
at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:319)
at org.apache.spark.sql.execution.datasources.DataSource.write(DataSource.scala:494)
at org.apache.spark.sql.DataFrameWriter.save(DataFrameWriter.scala:211)
```
Actually, the bug fix is simple. [`DataSource.createRelation(sparkSession.sqlContext, mode, options, data)`](https://github.com/gatorsmile/spark/blob/dd644f8117e889cebd6caca58702a7c7e3d88bef/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSource.scala#L429) already returns a BaseRelation. We should not assign schema to `userSpecifiedSchema`. That schema assignment only makes sense for the data sources that extend `FileFormat`.
#### How was this patch tested?
Added a test case.
Author: gatorsmile <gatorsmile@gmail.com>
Closes #14075 from gatorsmile/dataSource.
---
.../execution/datasources/DataSource.scala | 5 ++-
.../sql/test/DataFrameReaderWriterSuite.scala | 32 +++++++++++++++++++
2 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSource.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSource.scala
index 6dc27c1952..f572b93991 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSource.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSource.scala
@@ -485,12 +485,11 @@ case class DataSource(
data.logicalPlan,
mode)
sparkSession.sessionState.executePlan(plan).toRdd
+ // Replace the schema with that of the DataFrame we just wrote out to avoid re-inferring it.
+ copy(userSpecifiedSchema = Some(data.schema.asNullable)).resolveRelation()
case _ =>
sys.error(s"${providingClass.getCanonicalName} does not allow create table as select.")
}
-
- // We replace the schema with that of the DataFrame we just wrote out to avoid re-inferring it.
- copy(userSpecifiedSchema = Some(data.schema.asNullable)).resolveRelation()
}
}
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/test/DataFrameReaderWriterSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/test/DataFrameReaderWriterSuite.scala
index d454100ccb..05935cec4b 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/test/DataFrameReaderWriterSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/test/DataFrameReaderWriterSuite.scala
@@ -82,6 +82,29 @@ class DefaultSource
}
}
+/** Dummy provider with only RelationProvider and CreatableRelationProvider. */
+class DefaultSourceWithoutUserSpecifiedSchema
+ extends RelationProvider
+ with CreatableRelationProvider {
+
+ case class FakeRelation(sqlContext: SQLContext) extends BaseRelation {
+ override def schema: StructType = StructType(Seq(StructField("a", StringType)))
+ }
+
+ override def createRelation(
+ sqlContext: SQLContext,
+ parameters: Map[String, String]): BaseRelation = {
+ FakeRelation(sqlContext)
+ }
+
+ override def createRelation(
+ sqlContext: SQLContext,
+ mode: SaveMode,
+ parameters: Map[String, String],
+ data: DataFrame): BaseRelation = {
+ FakeRelation(sqlContext)
+ }
+}
class DataFrameReaderWriterSuite extends QueryTest with SharedSQLContext with BeforeAndAfter {
@@ -120,6 +143,15 @@ class DataFrameReaderWriterSuite extends QueryTest with SharedSQLContext with Be
.save()
}
+ test("resolve default source without extending SchemaRelationProvider") {
+ spark.read
+ .format("org.apache.spark.sql.test.DefaultSourceWithoutUserSpecifiedSchema")
+ .load()
+ .write
+ .format("org.apache.spark.sql.test.DefaultSourceWithoutUserSpecifiedSchema")
+ .save()
+ }
+
test("resolve full class") {
spark.read
.format("org.apache.spark.sql.test.DefaultSource")
--
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