DRILL-1299: Enable short circuit evaluation for case expressions in the run-time generated code.

2 files changed, 14 insertions, 0 deletions

diff --git a/exec/java-exec/src/main/java/org/apache/drill/exec/expr/EvaluationVisitor.java b/exec/java-exec/src/main/java/org/apache/drill/exec/expr/EvaluationVisitor.java
index cf3924640..de71eec0c 100644
--- a/exec/java-exec/src/main/java/org/apache/drill/exec/expr/EvaluationVisitor.java
+++ b/exec/java-exec/src/main/java/org/apache/drill/exec/expr/EvaluationVisitor.java
@@ -160,7 +160,12 @@ public class EvaluationVisitor {
         }
       }
 
+      generator.nestEvalBlock(jc._then());
+
       HoldingContainer thenExpr = c.expression.accept(this, generator);
+
+      generator.unNestEvalBlock();
+
       if (thenExpr.isOptional()) {
         JConditional newCond = jc._then()._if(thenExpr.getIsSet().ne(JExpr.lit(0)));
         JBlock b = newCond._then();
@@ -170,7 +175,12 @@ public class EvaluationVisitor {
         jc._then().assign(output.getHolder(), thenExpr.getHolder());
       }
 
+      generator.nestEvalBlock(jc._else());
+
       HoldingContainer elseExpr = ifExpr.elseExpression.accept(this, generator);
+
+      generator.unNestEvalBlock();
+
       if (elseExpr.isOptional()) {
         JConditional newCond = jc._else()._if(elseExpr.getIsSet().ne(JExpr.lit(0)));
         JBlock b = newCond._then();
diff --git a/exec/java-exec/src/test/java/org/apache/drill/TestExampleQueries.java b/exec/java-exec/src/test/java/org/apache/drill/TestExampleQueries.java
index 57d4043c5..58a18137b 100644
--- a/exec/java-exec/src/test/java/org/apache/drill/TestExampleQueries.java
+++ b/exec/java-exec/src/test/java/org/apache/drill/TestExampleQueries.java
@@ -471,4 +471,8 @@ public class TestExampleQueries extends BaseTestQuery{
     test("select t1.name, t1.kind, t2.n_nationkey from (select * from sys.options) t1 join (select * from cp.`tpch/nation.parquet`) t2 on t1.name = t2.n_name;");
   }
 
+  @Test
+  public void testCase() throws Exception {
+    test("select case when n_nationkey > 0 and n_nationkey < 2 then concat(n_name, '_abc') when n_nationkey >=2 and n_nationkey < 4 then '_EFG' else concat(n_name,'_XYZ') end from cp.`tpch/nation.parquet` ;");
+  }
 }