diff --git a/ql/src/java/org/apache/hadoop/hive/ql/optimizer/GenMapRedUtils.java b/ql/src/java/org/apache/hadoop/hive/ql/optimizer/GenMapRedUtils.java
index cf09e4932f70..8f269d8d2e40 100644
--- a/ql/src/java/org/apache/hadoop/hive/ql/optimizer/GenMapRedUtils.java
+++ b/ql/src/java/org/apache/hadoop/hive/ql/optimizer/GenMapRedUtils.java
@@ -388,6 +388,13 @@ public static void joinUnionPlan(GenMRProcContext opProcCtx,
     setUnionPlan(opProcCtx, local, plan, uCtx, true);
 
     List<Task<? extends Serializable>> parTasks = null;
+    if (opProcCtx.getRootTasks().contains(currentUnionTask)) {
+      opProcCtx.getRootTasks().remove(currentUnionTask);
+      if (!opProcCtx.getRootTasks().contains(existingTask)) {
+        opProcCtx.getRootTasks().add(existingTask);
+      }
+    }
+
     if ((currentUnionTask != null) && (currentUnionTask.getParentTasks() != null)
         && !currentUnionTask.getParentTasks().isEmpty()) {
       parTasks = new ArrayList<Task<? extends Serializable>>();
diff --git a/ql/src/test/queries/clientpositive/union27.q b/ql/src/test/queries/clientpositive/union27.q
new file mode 100644
index 000000000000..e0fccfcd7282
--- /dev/null
+++ b/ql/src/test/queries/clientpositive/union27.q
@@ -0,0 +1,4 @@
+create table jackson_sev_same as select * from src;
+create table dim_pho as select * from src;
+create table jackson_sev_add as select * from src;
+select b.* from jackson_sev_same a join (select * from dim_pho union all select * from jackson_sev_add)b on a.key=b.key and b.key=97;
diff --git a/ql/src/test/results/clientpositive/union27.q.out b/ql/src/test/results/clientpositive/union27.q.out
new file mode 100644
index 000000000000..af15e87d9875
--- /dev/null
+++ b/ql/src/test/results/clientpositive/union27.q.out
@@ -0,0 +1,41 @@
+PREHOOK: query: create table jackson_sev_same as select * from src
+PREHOOK: type: CREATETABLE_AS_SELECT
+PREHOOK: Input: default@src
+POSTHOOK: query: create table jackson_sev_same as select * from src
+POSTHOOK: type: CREATETABLE_AS_SELECT
+POSTHOOK: Input: default@src
+POSTHOOK: Output: default@jackson_sev_same
+PREHOOK: query: create table dim_pho as select * from src
+PREHOOK: type: CREATETABLE_AS_SELECT
+PREHOOK: Input: default@src
+POSTHOOK: query: create table dim_pho as select * from src
+POSTHOOK: type: CREATETABLE_AS_SELECT
+POSTHOOK: Input: default@src
+POSTHOOK: Output: default@dim_pho
+PREHOOK: query: create table jackson_sev_add as select * from src
+PREHOOK: type: CREATETABLE_AS_SELECT
+PREHOOK: Input: default@src
+POSTHOOK: query: create table jackson_sev_add as select * from src
+POSTHOOK: type: CREATETABLE_AS_SELECT
+POSTHOOK: Input: default@src
+POSTHOOK: Output: default@jackson_sev_add
+PREHOOK: query: select b.* from jackson_sev_same a join (select * from dim_pho union all select * from jackson_sev_add)b on a.key=b.key and b.key=97
+PREHOOK: type: QUERY
+PREHOOK: Input: default@dim_pho
+PREHOOK: Input: default@jackson_sev_add
+PREHOOK: Input: default@jackson_sev_same
+#### A masked pattern was here ####
+POSTHOOK: query: select b.* from jackson_sev_same a join (select * from dim_pho union all select * from jackson_sev_add)b on a.key=b.key and b.key=97
+POSTHOOK: type: QUERY
+POSTHOOK: Input: default@dim_pho
+POSTHOOK: Input: default@jackson_sev_add
+POSTHOOK: Input: default@jackson_sev_same
+#### A masked pattern was here ####
+97	val_97
+97	val_97
+97	val_97
+97	val_97
+97	val_97
+97	val_97
+97	val_97
+97	val_97