Fix isCascadingTruncateTable for AggregatedDialect.

viirya · viirya · commit 803b1961a34d · 2017-09-20T04:52:08.000Z
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/jdbc/AggregatedDialect.scala b/sql/core/src/main/scala/org/apache/spark/sql/jdbc/AggregatedDialect.scala
@@ -43,6 +43,17 @@ private class AggregatedDialect(dialects: List[JdbcDialect]) extends JdbcDialect
   }
 
   override def isCascadingTruncateTable(): Option[Boolean] = {
-    dialects.flatMap(_.isCascadingTruncateTable()).reduceOption(_ || _)
+    // If any dialect claims cascading truncate, this dialect is also cascading truncate.
+    // Otherwise, if any dialect has unknown cascading truncate, this dialect is also unknown.
+    val cascading = dialects.flatMap(_.isCascadingTruncateTable()).reduceOption(_ || _)
+    if (cascading.get) {
+      cascading
+    } else {
+      if (dialects.exists(_.isCascadingTruncateTable().isEmpty)) {
+        None
+      } else {
+        Some(false)
+      }
+    }
   }
 }
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/jdbc/JDBCSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/jdbc/JDBCSuite.scala
@@ -747,6 +747,19 @@ class JDBCSuite extends SparkFunSuite
     assert(agg.getCatalystType(0, "", 1, null) === Some(LongType))
     assert(agg.getCatalystType(1, "", 1, null) === Some(StringType))
     assert(agg.isCascadingTruncateTable() === Some(true))
+
+    val agg2 = new AggregatedDialect(List(new JdbcDialect {
+      override def canHandle(url: String) : Boolean = url.startsWith("jdbc:h2:")
+      override def getCatalystType(
+          sqlType: Int, typeName: String, size: Int, md: MetadataBuilder): Option[DataType] =
+        if (sqlType % 2 == 0) {
+          Some(LongType)
+        } else {
+          None
+        }
+      override def isCascadingTruncateTable(): Option[Boolean] = Some(false)
+    }, testH2Dialect))
+    assert(agg2.isCascadingTruncateTable() === None)
   }
 
   test("DB2Dialect type mapping") {

Original file line number	Diff line number	Diff line change
`@@ -43,6 +43,17 @@ private class AggregatedDialect(dialects: List[JdbcDialect]) extends JdbcDialect`
`43`	`43`	`}`
`44`	`44`
`45`	`45`	`override def isCascadingTruncateTable(): Option[Boolean] = {`
`46`		`- dialects.flatMap(_.isCascadingTruncateTable()).reduceOption(_ \|\| _)`
	`46`	`+ // If any dialect claims cascading truncate, this dialect is also cascading truncate.`
	`47`	`+ // Otherwise, if any dialect has unknown cascading truncate, this dialect is also unknown.`
	`48`	`+ val cascading = dialects.flatMap(_.isCascadingTruncateTable()).reduceOption(_ \|\| _)`
	`49`	`+ if (cascading.get) {`
	`50`	`+ cascading`
	`51`	`+ } else {`
	`52`	`+ if (dialects.exists(_.isCascadingTruncateTable().isEmpty)) {`
	`53`	`+ None`
	`54`	`+ } else {`
	`55`	`+ Some(false)`
	`56`	`+ }`
	`57`	`+ }`
`47`	`58`	`}`
`48`	`59`	`}`