Fixed count(*) issue when MV is created with simple projection.

apache · May 21, 2019 · 7b66f81 · 7b66f81
1 parent 4d7c8ad
commit 7b66f81
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Showing 2 changed files with 14 additions and 1 deletion.
diff --git a/datamap/mv/core/src/main/scala/org/apache/carbondata/mv/rewrite/DefaultMatchMaker.scala b/datamap/mv/core/src/main/scala/org/apache/carbondata/mv/rewrite/DefaultMatchMaker.scala
@@ -179,7 +179,9 @@ object SelectSelectNoChildDelta extends DefaultMatchPattern with PredicateHelper
           sel_1q.predicateList.exists(_.semanticEquals(expr)))
         val isPredicateEmdR = sel_1q.predicateList.forall(expr =>
           isDerivable(expr, sel_1a.outputList ++ rejoinOutputList, sel_1q, sel_1a, None))
-        val isOutputEdR = sel_1q.outputList.forall(expr =>
+        // Check if sel_1q.outputList is non empty and then check whether
+        // it can be derivable with sel_1a otherwise for empty cases it returns true.
+        val isOutputEdR = sel_1q.outputList.nonEmpty && sel_1q.outputList.forall(expr =>
           isDerivable(expr, sel_1a.outputList ++ rejoinOutputList, sel_1q, sel_1a, None))
 
         if (isUniqueRmE.isEmpty && isUniqueEmR.isEmpty && extrajoin.isEmpty && isPredicateRmE &&

diff --git a/datamap/mv/core/src/test/scala/org/apache/carbondata/mv/rewrite/MVCreateTestCase.scala b/datamap/mv/core/src/test/scala/org/apache/carbondata/mv/rewrite/MVCreateTestCase.scala
@@ -1019,6 +1019,17 @@ class MVCreateTestCase extends QueryTest with BeforeAndAfterAll {
     sql("drop table if exists all_table")
   }
 
+  test("count test case") {
+
+    sql("drop table if exists mvtable1")
+    sql("create table mvtable1(name string,age int,salary int) stored by 'carbondata'")
+    sql("create datamap MV11 using 'mv' as select name from mvtable1")
+    sql(" insert into mvtable1 select 'n1',12,12")
+    sql("rebuild datamap MV11")
+    checkAnswer(sql("select count(*) from mvtable1"),Seq(Row(1)))
+    sql("drop table if exists mvtable1")
+  }
+
   def verifyMVDataMap(logicalPlan: LogicalPlan, dataMapName: String): Boolean = {
     val tables = logicalPlan collect {
       case l: LogicalRelation => l.catalogTable.get