diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/AbstractIntroduceAccessMethodRule.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/AbstractIntroduceAccessMethodRule.java
index 6583342..cdc76e6 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/AbstractIntroduceAccessMethodRule.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/AbstractIntroduceAccessMethodRule.java
@@ -412,12 +412,12 @@
             }
             // If the access method requires all exprs to be matched but they
             // are not, remove this candidate.
-            if (!allUsed && accessMethod.matchAllIndexExprs()) {
+            if (!allUsed && accessMethod.matchAllIndexExprs(index)) {
                 indexExprAndVarIt.remove();
                 continue;
             }
             // A prefix of the index exprs may have been matched.
-            if (accessMethod.matchPrefixIndexExprs()) {
+            if (accessMethod.matchPrefixIndexExprs(index)) {
                 if (lastFieldMatched < 0) {
                     indexExprAndVarIt.remove();
                     continue;
diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/BTreeAccessMethod.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/BTreeAccessMethod.java
index 0bcc202..4b6fc36 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/BTreeAccessMethod.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/BTreeAccessMethod.java
@@ -122,13 +122,27 @@
     }
 
     @Override
-    public boolean matchAllIndexExprs() {
-        return false;
+    public boolean matchAllIndexExprs(Index index) {
+        // require all expressions to be matched if this is a composite key index which has an unknownable key field.
+        // because we only add a tuple to the index if all its key fields are not null/missing.
+        return index.getKeyFieldTypes().size() > 1 && hasUnknownableField(index);
     }
 
     @Override
-    public boolean matchPrefixIndexExprs() {
-        return true;
+    public boolean matchPrefixIndexExprs(Index index) {
+        return !matchAllIndexExprs(index);
+    }
+
+    private boolean hasUnknownableField(Index index) {
+        if (index.isSecondaryIndex() && index.isOverridingKeyFieldTypes() && !index.isEnforced()) {
+            return true;
+        }
+        for (IAType fieldType : index.getKeyFieldTypes()) {
+            if (NonTaggedFormatUtil.isOptional(fieldType)) {
+                return true;
+            }
+        }
+        return false;
     }
 
     @Override
diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/IAccessMethod.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/IAccessMethod.java
index 94de169..8cd0de4 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/IAccessMethod.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/IAccessMethod.java
@@ -69,16 +69,18 @@
      * index to be applicable.
      *
      * @return boolean
+     * @param index
      */
-    public boolean matchAllIndexExprs();
+    public boolean matchAllIndexExprs(Index index);
 
     /**
      * Indicates whether this index is applicable if only a prefix of the index
      * expressions are matched.
      *
      * @return boolean
+     * @param index
      */
-    public boolean matchPrefixIndexExprs();
+    public boolean matchPrefixIndexExprs(Index index);
 
     /**
      * Applies the plan transformation to use chosenIndex to optimize a selection query.
diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/InvertedIndexAccessMethod.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/InvertedIndexAccessMethod.java
index ca65a9e..1be0ce0 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/InvertedIndexAccessMethod.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/InvertedIndexAccessMethod.java
@@ -381,12 +381,12 @@
     }
 
     @Override
-    public boolean matchAllIndexExprs() {
+    public boolean matchAllIndexExprs(Index index) {
         return true;
     }
 
     @Override
-    public boolean matchPrefixIndexExprs() {
+    public boolean matchPrefixIndexExprs(Index index) {
         return false;
     }
 
diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/RTreeAccessMethod.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/RTreeAccessMethod.java
index 7a24a8b..5ae4b4d 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/RTreeAccessMethod.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/am/RTreeAccessMethod.java
@@ -95,12 +95,12 @@
     }
 
     @Override
-    public boolean matchAllIndexExprs() {
+    public boolean matchAllIndexExprs(Index index) {
         return true;
     }
 
     @Override
-    public boolean matchPrefixIndexExprs() {
+    public boolean matchPrefixIndexExprs(Index index) {
         return false;
     }
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/btree-index-selection/btree-index-composite-key-04.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/btree-index-selection/btree-index-composite-key-04.sqlpp
new file mode 100644
index 0000000..e9afad8
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/btree-index-selection/btree-index-composite-key-04.sqlpp
@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Description     : Define BTree index on a composite key (fname,lname?)
+ *                 : Query predicate => where fname="..."
+ *                 : Currently this index cannot be used for this query because
+ *                 : the index will not store composite keys where some fields are NULL/MISSING.
+ * Expected Result : Success
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+
+use test;
+
+create type test.Emp as
+ closed {
+  id : bigint,
+  fname : string,
+  lname : string?
+};
+
+create dataset employee(Emp) primary key id;
+
+create index idx_employee_f_l_name on employee (fname,lname) type btree;
+
+select id, fname, lname
+from employee
+where fname = "A"
+order by id;
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/01.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/01.sqlpp
index 792dde1..f42caf5 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/01.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/01.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
 /*
- * Description  : Testing that creating a nested composite key open index is successful and being used.
+ * Description  : Testing that creating a nested composite key open index is successful.
+ *              : Currently this index cannot be used for this query because
+ *              : the index will not store composite keys where some fields are NULL/MISSING.
  * Expected Res : Success
  */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/02.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/02.sqlpp
index 438ea9b..33afe2a 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/02.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/02.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
 /*
- * Description  : Testing that creating a nested composite key open index is successful and being used.
+ * Description  : Testing that creating a nested composite key open index is successful.
+ *              : Currently this index cannot be used for this query because
+ *              : the index will not store composite keys where some fields are NULL/MISSING.
  * Expected Res : Success
  */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/06.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/06.sqlpp
index b10915d..16ac025 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/06.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/06.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
 /*
- * Description  : Index join because there's a hint and the probe type is known (string), non-enforced nested composite
+ * Description  : There's index-join hint and the probe type is known (string), non-enforced nested composite index.
+ *              : Currently this index cannot be used for this query because
+ *              : the index will not store composite keys where some fields are NULL/MISSING.
  * Expected Res : Success
  */
 drop dataverse test if exists;
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/07.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/07.sqlpp
index 9dce6972..e8d18cf 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/07.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/07.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
 /*
- * Description  : Index join because there's a hint and the probe type is known (bigint), non-enforced nested composite
+ * Description  : There's index-join join and the probe type is known (bigint), non-enforced nested composite index.
+ *              : Currently this index cannot be used for this query because
+ *              : the index will not store composite keys where some fields are NULL/MISSING.
  * Expected Res : Success
  */
 drop dataverse test if exists;
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/01.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/01.sqlpp
index 6f97c35..df0510f 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/01.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/01.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
 /*
- *  Description     : Testing that creating a nested composite key open index is successful and being used.
+ *  Description     : Testing that creating a nested composite key open index is successful.
+ *                  : Currently this index cannot be used for this query because
+ *                  : the index will not store composite keys where some fields are NULL/MISSING.
  *  Expected Result : Success
  */
 drop  dataverse test if exists;
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/02.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/02.sqlpp
index 0fc5b4e..b9585f9 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/02.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/02.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
 /*
- *  Description     : Testing that creating a nested composite key open index is successful and being used.
+ *  Description     : Testing that creating a nested composite key open index is successful.
+ *                  : Currently this index cannot be used for this query because
+ *                  : the index will not store composite keys where some fields are NULL/MISSING.
  *  Expected Result : Success
  */
 drop  dataverse test if exists;
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/03.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/03.sqlpp
index 45f87fe..067d6b9 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/03.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/03.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/04.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/04.sqlpp
index 534df4c..3ca76d7 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/04.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/04.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/05.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/05.sqlpp
index ae384bd..1aec248 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/05.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/05.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/06.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/06.sqlpp
index d7aa320..352e390 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/06.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/06.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/07.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/07.sqlpp
index bc7b0a9..640f3c9 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/07.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/07.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/08.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/08.sqlpp
index 094c8b3..cba8aa5 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/08.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/08.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/09.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/09.sqlpp
index 37a6e97..fd8f8bc 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/09.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/09.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/10.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/10.sqlpp
index 6cd28df4..e5a189a 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/10.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/10.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/11.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/11.sqlpp
index 9024f4e..080389a 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/11.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/11.sqlpp
@@ -17,7 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/12.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/12.sqlpp
index 546a041..7b0a51a 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/12.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/nested-open-index/btree-index/non-enforced-composite-key/12.sqlpp
@@ -17,8 +17,9 @@
  * under the License.
  */
  /*
-  *  Description     : Testing that creating a nested composite key open index is successful and being used
-  *                    when multiple indexes match.
+  *  Description     : Testing that creating a nested composite key open index is successful.
+  *                  : Currently this index cannot be used for this query because
+  *                  : the index will not store composite keys where some fields are NULL/MISSING.
   *  Expected Result : Success
   */
 
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/open-index-non-enforced/btree-composite-key-non-enforced/btree-composite-key-non-enforced-03.sqlpp b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/open-index-non-enforced/btree-composite-key-non-enforced/btree-composite-key-non-enforced-03.sqlpp
index b644b15..4b44ca8 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/queries/open-index-non-enforced/btree-composite-key-non-enforced/btree-composite-key-non-enforced-03.sqlpp
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/queries/open-index-non-enforced/btree-composite-key-non-enforced/btree-composite-key-non-enforced-03.sqlpp
@@ -22,6 +22,8 @@
 *              : fields of a composite index.
 *              : Define the BTree index on a composite key (c_x,c_y,c_z)
 *              : predicate => WHERE c_x = ... and c_z = ...
+*              : Currently this index cannot be used for this query because
+*              : the index will not store composite keys where some fields are NULL/MISSING.
 * Expected Res : Success
 * Date         : 10 Oct 2019
 */
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/btree-index-selection/btree-index-composite-key-04.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/btree-index-selection/btree-index-composite-key-04.plan
new file mode 100644
index 0000000..6699455
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/btree-index-selection/btree-index-composite-key-04.plan
@@ -0,0 +1,12 @@
+-- DISTRIBUTE_RESULT  |PARTITIONED|
+  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+    -- STREAM_PROJECT  |PARTITIONED|
+      -- ASSIGN  |PARTITIONED|
+        -- SORT_MERGE_EXCHANGE [$$20(ASC) ]  |PARTITIONED|
+          -- STREAM_SELECT  |PARTITIONED|
+            -- STREAM_PROJECT  |PARTITIONED|
+              -- ASSIGN  |PARTITIONED|
+                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                  -- DATASOURCE_SCAN  |PARTITIONED|
+                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                      -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/01.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/01.plan
index 36e3477..b725169 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/01.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/01.plan
@@ -3,20 +3,19 @@
     -- STREAM_PROJECT  |PARTITIONED|
       -- ASSIGN  |PARTITIONED|
         -- STREAM_PROJECT  |PARTITIONED|
-          -- STREAM_SELECT  |PARTITIONED|
-            -- STREAM_PROJECT  |PARTITIONED|
-              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                -- BTREE_SEARCH  |PARTITIONED|
-                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                    -- STABLE_SORT [$$38(ASC)]  |PARTITIONED|
-                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                        -- STREAM_PROJECT  |PARTITIONED|
-                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
-                              -- BROADCAST_EXCHANGE  |PARTITIONED|
-                                -- ASSIGN  |PARTITIONED|
-                                  -- STREAM_PROJECT  |PARTITIONED|
-                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                      -- DATASOURCE_SCAN  |PARTITIONED|
-                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+            -- HYBRID_HASH_JOIN [$$31][$$32]  |PARTITIONED|
+              -- HASH_PARTITION_EXCHANGE [$$31]  |PARTITIONED|
+                -- ASSIGN  |PARTITIONED|
+                  -- STREAM_PROJECT  |PARTITIONED|
+                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                      -- DATASOURCE_SCAN  |PARTITIONED|
+                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+              -- HASH_PARTITION_EXCHANGE [$$32]  |PARTITIONED|
+                -- ASSIGN  |PARTITIONED|
+                  -- STREAM_PROJECT  |PARTITIONED|
+                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                      -- DATASOURCE_SCAN  |PARTITIONED|
+                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/02.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/02.plan
index 8e2bd43..b725169 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/02.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/02.plan
@@ -3,20 +3,19 @@
     -- STREAM_PROJECT  |PARTITIONED|
       -- ASSIGN  |PARTITIONED|
         -- STREAM_PROJECT  |PARTITIONED|
-          -- STREAM_SELECT  |PARTITIONED|
-            -- STREAM_PROJECT  |PARTITIONED|
-              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                -- BTREE_SEARCH  |PARTITIONED|
-                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                    -- STABLE_SORT [$$39(ASC)]  |PARTITIONED|
-                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                        -- STREAM_PROJECT  |PARTITIONED|
-                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
-                              -- BROADCAST_EXCHANGE  |PARTITIONED|
-                                -- ASSIGN  |PARTITIONED|
-                                  -- STREAM_PROJECT  |PARTITIONED|
-                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                      -- DATASOURCE_SCAN  |PARTITIONED|
-                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+            -- HYBRID_HASH_JOIN [$$31][$$32]  |PARTITIONED|
+              -- HASH_PARTITION_EXCHANGE [$$31]  |PARTITIONED|
+                -- ASSIGN  |PARTITIONED|
+                  -- STREAM_PROJECT  |PARTITIONED|
+                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                      -- DATASOURCE_SCAN  |PARTITIONED|
+                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+              -- HASH_PARTITION_EXCHANGE [$$32]  |PARTITIONED|
+                -- ASSIGN  |PARTITIONED|
+                  -- STREAM_PROJECT  |PARTITIONED|
+                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                      -- DATASOURCE_SCAN  |PARTITIONED|
+                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/06.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/06.plan
index 34d10fc..cb6c83f 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/06.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/06.plan
@@ -6,26 +6,25 @@
           -- STABLE_SORT [$$44(ASC), $$45(ASC)]  |PARTITIONED|
             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
               -- STREAM_PROJECT  |PARTITIONED|
-                -- STREAM_SELECT  |PARTITIONED|
-                  -- ASSIGN  |PARTITIONED|
-                    -- STREAM_PROJECT  |PARTITIONED|
-                      -- ASSIGN  |PARTITIONED|
-                        -- STREAM_PROJECT  |PARTITIONED|
-                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
-                              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STABLE_SORT [$$52(ASC)]  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STREAM_PROJECT  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- BTREE_SEARCH  |PARTITIONED|
-                                          -- BROADCAST_EXCHANGE  |PARTITIONED|
-                                            -- STREAM_PROJECT  |PARTITIONED|
-                                              -- ASSIGN  |PARTITIONED|
-                                                -- STREAM_PROJECT  |PARTITIONED|
-                                                  -- ASSIGN  |PARTITIONED|
-                                                    -- STREAM_PROJECT  |PARTITIONED|
-                                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                        -- DATASOURCE_SCAN  |PARTITIONED|
-                                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                  -- HYBRID_HASH_JOIN [$$41][$$42]  |PARTITIONED|
+                    -- HASH_PARTITION_EXCHANGE [$$41]  |PARTITIONED|
+                      -- STREAM_PROJECT  |PARTITIONED|
+                        -- ASSIGN  |PARTITIONED|
+                          -- STREAM_PROJECT  |PARTITIONED|
+                            -- ASSIGN  |PARTITIONED|
+                              -- STREAM_PROJECT  |PARTITIONED|
+                                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                  -- DATASOURCE_SCAN  |PARTITIONED|
+                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                      -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                    -- HASH_PARTITION_EXCHANGE [$$42]  |PARTITIONED|
+                      -- STREAM_PROJECT  |PARTITIONED|
+                        -- ASSIGN  |PARTITIONED|
+                          -- STREAM_PROJECT  |PARTITIONED|
+                            -- ASSIGN  |PARTITIONED|
+                              -- STREAM_PROJECT  |PARTITIONED|
+                                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                  -- DATASOURCE_SCAN  |PARTITIONED|
+                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                      -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/07.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/07.plan
index 34d10fc..cb6c83f 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/07.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index-join/non-enforced-composite-key-equi-join/07.plan
@@ -6,26 +6,25 @@
           -- STABLE_SORT [$$44(ASC), $$45(ASC)]  |PARTITIONED|
             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
               -- STREAM_PROJECT  |PARTITIONED|
-                -- STREAM_SELECT  |PARTITIONED|
-                  -- ASSIGN  |PARTITIONED|
-                    -- STREAM_PROJECT  |PARTITIONED|
-                      -- ASSIGN  |PARTITIONED|
-                        -- STREAM_PROJECT  |PARTITIONED|
-                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
-                              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STABLE_SORT [$$52(ASC)]  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STREAM_PROJECT  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- BTREE_SEARCH  |PARTITIONED|
-                                          -- BROADCAST_EXCHANGE  |PARTITIONED|
-                                            -- STREAM_PROJECT  |PARTITIONED|
-                                              -- ASSIGN  |PARTITIONED|
-                                                -- STREAM_PROJECT  |PARTITIONED|
-                                                  -- ASSIGN  |PARTITIONED|
-                                                    -- STREAM_PROJECT  |PARTITIONED|
-                                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                        -- DATASOURCE_SCAN  |PARTITIONED|
-                                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                  -- HYBRID_HASH_JOIN [$$41][$$42]  |PARTITIONED|
+                    -- HASH_PARTITION_EXCHANGE [$$41]  |PARTITIONED|
+                      -- STREAM_PROJECT  |PARTITIONED|
+                        -- ASSIGN  |PARTITIONED|
+                          -- STREAM_PROJECT  |PARTITIONED|
+                            -- ASSIGN  |PARTITIONED|
+                              -- STREAM_PROJECT  |PARTITIONED|
+                                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                  -- DATASOURCE_SCAN  |PARTITIONED|
+                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                      -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                    -- HASH_PARTITION_EXCHANGE [$$42]  |PARTITIONED|
+                      -- STREAM_PROJECT  |PARTITIONED|
+                        -- ASSIGN  |PARTITIONED|
+                          -- STREAM_PROJECT  |PARTITIONED|
+                            -- ASSIGN  |PARTITIONED|
+                              -- STREAM_PROJECT  |PARTITIONED|
+                                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                  -- DATASOURCE_SCAN  |PARTITIONED|
+                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                      -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/01.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/01.plan
index 31fd806..06194e4 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/01.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/01.plan
@@ -3,13 +3,6 @@
     -- STREAM_SELECT  |PARTITIONED|
       -- STREAM_PROJECT  |PARTITIONED|
         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-          -- BTREE_SEARCH  |PARTITIONED|
+          -- DATASOURCE_SCAN  |PARTITIONED|
             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-              -- STABLE_SORT [$$20(ASC)]  |PARTITIONED|
-                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                  -- STREAM_PROJECT  |PARTITIONED|
-                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                      -- BTREE_SEARCH  |PARTITIONED|
-                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                          -- ASSIGN  |PARTITIONED|
-                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/02.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/02.plan
index eb0128b..06194e4 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/02.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/02.plan
@@ -3,13 +3,6 @@
     -- STREAM_SELECT  |PARTITIONED|
       -- STREAM_PROJECT  |PARTITIONED|
         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-          -- BTREE_SEARCH  |PARTITIONED|
+          -- DATASOURCE_SCAN  |PARTITIONED|
             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-              -- STABLE_SORT [$$23(ASC)]  |PARTITIONED|
-                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                  -- STREAM_PROJECT  |PARTITIONED|
-                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                      -- BTREE_SEARCH  |PARTITIONED|
-                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                          -- ASSIGN  |PARTITIONED|
-                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/03.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/03.plan
index a12e373d..4684702 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/03.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/03.plan
@@ -10,13 +10,6 @@
                   -- ASSIGN  |PARTITIONED|
                     -- STREAM_PROJECT  |PARTITIONED|
                       -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                        -- BTREE_SEARCH  |PARTITIONED|
+                        -- DATASOURCE_SCAN  |PARTITIONED|
                           -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- STABLE_SORT [$$27(ASC)]  |PARTITIONED|
-                              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STREAM_PROJECT  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- BTREE_SEARCH  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- ASSIGN  |PARTITIONED|
-                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                            -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/04.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/04.plan
index d7b6547..5167ddd 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/04.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/04.plan
@@ -12,13 +12,6 @@
                       -- ASSIGN  |PARTITIONED|
                         -- STREAM_PROJECT  |PARTITIONED|
                           -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
+                            -- DATASOURCE_SCAN  |PARTITIONED|
                               -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STABLE_SORT [$$30(ASC)]  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STREAM_PROJECT  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- BTREE_SEARCH  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- ASSIGN  |PARTITIONED|
-                                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/05.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/05.plan
index d7b6547..5167ddd 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/05.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/05.plan
@@ -12,13 +12,6 @@
                       -- ASSIGN  |PARTITIONED|
                         -- STREAM_PROJECT  |PARTITIONED|
                           -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
+                            -- DATASOURCE_SCAN  |PARTITIONED|
                               -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STABLE_SORT [$$30(ASC)]  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STREAM_PROJECT  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- BTREE_SEARCH  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- ASSIGN  |PARTITIONED|
-                                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/06.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/06.plan
index 9373fcd..5167ddd 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/06.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/06.plan
@@ -12,13 +12,6 @@
                       -- ASSIGN  |PARTITIONED|
                         -- STREAM_PROJECT  |PARTITIONED|
                           -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
+                            -- DATASOURCE_SCAN  |PARTITIONED|
                               -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STABLE_SORT [$$29(ASC)]  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STREAM_PROJECT  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- BTREE_SEARCH  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- ASSIGN  |PARTITIONED|
-                                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/07.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/07.plan
index 9373fcd..5167ddd 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/07.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/07.plan
@@ -12,13 +12,6 @@
                       -- ASSIGN  |PARTITIONED|
                         -- STREAM_PROJECT  |PARTITIONED|
                           -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
+                            -- DATASOURCE_SCAN  |PARTITIONED|
                               -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STABLE_SORT [$$29(ASC)]  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STREAM_PROJECT  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- BTREE_SEARCH  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- ASSIGN  |PARTITIONED|
-                                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/08.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/08.plan
index 9373fcd..5167ddd 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/08.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/08.plan
@@ -12,13 +12,6 @@
                       -- ASSIGN  |PARTITIONED|
                         -- STREAM_PROJECT  |PARTITIONED|
                           -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
+                            -- DATASOURCE_SCAN  |PARTITIONED|
                               -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STABLE_SORT [$$29(ASC)]  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STREAM_PROJECT  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- BTREE_SEARCH  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- ASSIGN  |PARTITIONED|
-                                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/09.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/09.plan
index 9373fcd..5167ddd 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/09.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/09.plan
@@ -12,13 +12,6 @@
                       -- ASSIGN  |PARTITIONED|
                         -- STREAM_PROJECT  |PARTITIONED|
                           -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
+                            -- DATASOURCE_SCAN  |PARTITIONED|
                               -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STABLE_SORT [$$29(ASC)]  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STREAM_PROJECT  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- BTREE_SEARCH  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- ASSIGN  |PARTITIONED|
-                                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/10.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/10.plan
index 9373fcd..5167ddd 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/10.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/10.plan
@@ -12,13 +12,6 @@
                       -- ASSIGN  |PARTITIONED|
                         -- STREAM_PROJECT  |PARTITIONED|
                           -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
+                            -- DATASOURCE_SCAN  |PARTITIONED|
                               -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- STABLE_SORT [$$29(ASC)]  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STREAM_PROJECT  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- BTREE_SEARCH  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- ASSIGN  |PARTITIONED|
-                                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/11.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/11.plan
index af7f7c5..a4a940f 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/11.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/11.plan
@@ -13,13 +13,6 @@
                         -- ASSIGN  |PARTITIONED|
                           -- STREAM_PROJECT  |PARTITIONED|
                             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                              -- BTREE_SEARCH  |PARTITIONED|
+                              -- DATASOURCE_SCAN  |PARTITIONED|
                                 -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                  -- STABLE_SORT [$$34(ASC)]  |PARTITIONED|
-                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                      -- STREAM_PROJECT  |PARTITIONED|
-                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                          -- BTREE_SEARCH  |PARTITIONED|
-                                            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                              -- ASSIGN  |PARTITIONED|
-                                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                  -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/12.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/12.plan
index 15abe1c..c238677 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/12.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/nested-open-index/btree-index/non-enforced-composite-key/12.plan
@@ -12,24 +12,6 @@
                       -- ASSIGN  |PARTITIONED|
                         -- STREAM_PROJECT  |PARTITIONED|
                           -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                            -- BTREE_SEARCH  |PARTITIONED|
+                            -- DATASOURCE_SCAN  |PARTITIONED|
                               -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                -- INTERSECT  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STABLE_SORT [$$34(ASC)]  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- STREAM_PROJECT  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- BTREE_SEARCH  |PARTITIONED|
-                                              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                -- ASSIGN  |PARTITIONED|
-                                                  -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
-                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                    -- STABLE_SORT [$$38(ASC)]  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- STREAM_PROJECT  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- BTREE_SEARCH  |PARTITIONED|
-                                              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                -- ASSIGN  |PARTITIONED|
-                                                  -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results/open-index-non-enforced/btree-composite-key-non-enforced/btree-composite-key-non-enforced-03.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results/open-index-non-enforced/btree-composite-key-non-enforced/btree-composite-key-non-enforced-03.plan
index 1323261..3693813 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results/open-index-non-enforced/btree-composite-key-non-enforced/btree-composite-key-non-enforced-03.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results/open-index-non-enforced/btree-composite-key-non-enforced/btree-composite-key-non-enforced-03.plan
@@ -5,13 +5,6 @@
         -- ASSIGN  |PARTITIONED|
           -- STREAM_PROJECT  |PARTITIONED|
             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-              -- BTREE_SEARCH  |PARTITIONED|
+              -- DATASOURCE_SCAN  |PARTITIONED|
                 -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                  -- STABLE_SORT [$$26(ASC)]  |PARTITIONED|
-                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                      -- STREAM_PROJECT  |PARTITIONED|
-                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                          -- BTREE_SEARCH  |PARTITIONED|
-                            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                              -- ASSIGN  |PARTITIONED|
-                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
\ No newline at end of file
+                  -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.1.ddl.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.1.ddl.sqlpp
new file mode 100644
index 0000000..a0fc289
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.1.ddl.sqlpp
@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Description     : Define BTree index on a composite key (fname,lname?)
+ *                 : Query predicate => where fname="..."
+ *                 : Currently this index cannot be used for this query because
+ *                 : the index will not store composite keys where some fields are NULL/MISSING.
+ * Expected Result : Success
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+
+use test;
+
+create type test.Emp as
+ closed {
+  id : bigint,
+  fname : string,
+  lname : string?
+};
+
+create dataset employee(Emp) primary key id;
+
+create index idx_employee_f_l_name on employee (fname,lname) type btree;
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.2.update.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.2.update.sqlpp
new file mode 100644
index 0000000..3563057
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.2.update.sqlpp
@@ -0,0 +1,42 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Description     : Define BTree index on a composite key (fname,lname?)
+ *                 : Query predicate => where fname="..."
+ *                 : Currently this index cannot be used for this query because
+ *                 : the index will not store composite keys where some fields are NULL/MISSING.
+ * Expected Result : Success
+ */
+use test;
+
+insert into employee ({
+    "id": 1,
+    "fname": "A",
+    "lname": "X"
+});
+insert into employee ({
+    "id": 2,
+    "fname": "A"
+    /* "lname" is missing */
+});
+insert into employee ({
+    "id": 3,
+    "fname": "B",
+    "lname": "Y"
+});
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.3.query.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.3.query.sqlpp
new file mode 100644
index 0000000..691e4f6
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.3.query.sqlpp
@@ -0,0 +1,32 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Description     : Define BTree index on a composite key (fname,lname?)
+ *                 : Query predicate => where fname="..."
+ *                 : Currently this index cannot be used for this query because
+ *                 : the index will not store composite keys where some fields are NULL/MISSING.
+ * Expected Result : Success
+ */
+
+use test;
+
+select id, fname, lname
+from employee
+where fname = "A"
+order by id
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/results/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.3.adm b/asterixdb/asterix-app/src/test/resources/runtimets/results/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.3.adm
new file mode 100644
index 0000000..f853208
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/results/index-selection/btree-index-composite-key-04/btree-index-composite-key-04.3.adm
@@ -0,0 +1,2 @@
+{ "id": 1, "fname": "A", "lname": "X" }
+{ "id": 2, "fname": "A" }
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/results/nested-open-index/index-selection/non-enforced-02/non-enforced-02.4.adm b/asterixdb/asterix-app/src/test/resources/runtimets/results/nested-open-index/index-selection/non-enforced-02/non-enforced-02.4.adm
index 66fa150..f36e389 100644
--- a/asterixdb/asterix-app/src/test/resources/runtimets/results/nested-open-index/index-selection/non-enforced-02/non-enforced-02.4.adm
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/results/nested-open-index/index-selection/non-enforced-02/non-enforced-02.4.adm
@@ -1 +1,2 @@
-{ "res": 3 }
\ No newline at end of file
+{ "res": 3 }
+{ "res": 7 }
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/results/open-index-non-enforced/index-selection/btree-index-02/btree-index-02.4.adm b/asterixdb/asterix-app/src/test/resources/runtimets/results/open-index-non-enforced/index-selection/btree-index-02/btree-index-02.4.adm
index 66fa150..f36e389 100644
--- a/asterixdb/asterix-app/src/test/resources/runtimets/results/open-index-non-enforced/index-selection/btree-index-02/btree-index-02.4.adm
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/results/open-index-non-enforced/index-selection/btree-index-02/btree-index-02.4.adm
@@ -1 +1,2 @@
-{ "res": 3 }
\ No newline at end of file
+{ "res": 3 }
+{ "res": 7 }
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml b/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
index 9ec7ccf..5ef5808 100644
--- a/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
@@ -5503,6 +5503,11 @@
       </compilation-unit>
     </test-case>
     <test-case FilePath="index-selection">
+      <compilation-unit name="btree-index-composite-key-04">
+        <output-dir compare="Text">btree-index-composite-key-04</output-dir>
+      </compilation-unit>
+    </test-case>
+    <test-case FilePath="index-selection">
       <compilation-unit name="btree-sec-primary-index">
         <output-dir compare="Text">btree-sec-primary-index</output-dir>
       </compilation-unit>
diff --git a/hyracks-fullstack/hyracks/hyracks-http/src/main/java/org/apache/hyracks/http/server/HttpServerHandler.java b/hyracks-fullstack/hyracks/hyracks-http/src/main/java/org/apache/hyracks/http/server/HttpServerHandler.java
index 0f4ce8a..77d3493 100644
--- a/hyracks-fullstack/hyracks/hyracks-http/src/main/java/org/apache/hyracks/http/server/HttpServerHandler.java
+++ b/hyracks-fullstack/hyracks/hyracks-http/src/main/java/org/apache/hyracks/http/server/HttpServerHandler.java
@@ -146,7 +146,7 @@
             HttpScheme scheme =
                     server.getScheme() == HttpScheme.HTTPS || "https".equals(request.headers().get(X_FORWARDED_PROTO))
                             ? HttpScheme.HTTPS : HttpScheme.HTTP;
-            servletRequest = HttpUtil.toServletRequest(ctx, request, scheme);
+            servletRequest = createServletRequest(ctx, request, scheme);
         } catch (IllegalArgumentException e) {
             LOGGER.log(Level.WARN, "Failure Decoding Request", e);
             respond(ctx, request, HttpResponseStatus.BAD_REQUEST);
@@ -174,6 +174,11 @@
                 response -> response.headers().set(HttpUtil.PERMANENT, "true"));
     }
 
+    protected IServletRequest createServletRequest(ChannelHandlerContext ctx, FullHttpRequest request,
+            HttpScheme scheme) {
+        return HttpUtil.toServletRequest(ctx, request, scheme);
+    }
+
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
         LOGGER.log(Level.WARN, "Failure handling HTTP Request", cause);
diff --git a/hyracks-fullstack/hyracks/hyracks-maven-plugins/license-automation-plugin/src/main/java/org/apache/hyracks/maven/license/SourcePointerResolver.java b/hyracks-fullstack/hyracks/hyracks-maven-plugins/license-automation-plugin/src/main/java/org/apache/hyracks/maven/license/SourcePointerResolver.java
index 5c4a081..8ac8b12 100644
--- a/hyracks-fullstack/hyracks/hyracks-maven-plugins/license-automation-plugin/src/main/java/org/apache/hyracks/maven/license/SourcePointerResolver.java
+++ b/hyracks-fullstack/hyracks/hyracks-maven-plugins/license-automation-plugin/src/main/java/org/apache/hyracks/maven/license/SourcePointerResolver.java
@@ -20,12 +20,13 @@
 
 import java.io.File;
 import java.io.IOException;
-import java.util.Collection;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Random;
 
 import org.apache.commons.io.FileUtils;
+import org.apache.commons.lang3.tuple.Pair;
 import org.apache.hyracks.maven.license.project.LicensedProjects;
 import org.apache.hyracks.maven.license.project.Project;
 import org.apache.maven.artifact.Artifact;
@@ -45,6 +46,7 @@
 
 public class SourcePointerResolver {
 
+    private static final String CENTRAL_REPO_ID = "central";
     private final GenerateFileMojo mojo;
 
     private SourcePointerResolver(GenerateFileMojo mojo) {
@@ -56,70 +58,85 @@
         instance.collectSourcePointers();
     }
 
-    private ArtifactRepository getCentralRepository() {
-        for (ArtifactRepository repo : mojo.getSession().getRequest().getRemoteRepositories()) {
-            if ("central".equals(repo.getId())) {
-                return repo;
+    /**
+     * @return an ArtifactRepository pair representing the {@code central} repository, where the left element is how to
+     *         reach the {@code central} repository, with the right element being the {@code central} repository itself.
+     *         Note that these only differ when using a mirror to access {@code central}
+     */
+    private Pair<ArtifactRepository, ArtifactRepository> getCentralRepository() {
+        for (ArtifactRepository candidate : mojo.getSession().getRequest().getRemoteRepositories()) {
+            if (CENTRAL_REPO_ID.equals(candidate.getId())) {
+                return Pair.of(candidate, candidate);
+            }
+            for (ArtifactRepository mirrored : candidate.getMirroredRepositories()) {
+                if (CENTRAL_REPO_ID.equals(mirrored.getId())) {
+                    return Pair.of(candidate, mirrored);
+                }
             }
         }
-        throw new IllegalStateException("Unable to find 'central' remote repository!");
+        throw new IllegalStateException("Unable to find '" + CENTRAL_REPO_ID + "' remote repository!");
     }
 
     private void collectSourcePointers() throws ProjectBuildingException, IOException {
+        List<Project> cddlProjects = new ArrayList<>();
+        for (LicensedProjects lp : mojo.getLicenseMap().values()) {
+            if (lp.getLicense().getDisplayName() != null
+                    && lp.getLicense().getDisplayName().toLowerCase().contains("cddl")) {
+                cddlProjects.addAll(lp.getProjects());
+            }
+        }
+        if (cddlProjects.isEmpty()) {
+            return;
+        }
         try (StubArtifactRepository stubRepo = new StubArtifactRepository()) {
             DefaultRepositoryRequest rr = new DefaultRepositoryRequest();
             rr.setLocalRepository(stubRepo);
-            ArtifactRepository central = getCentralRepository();
-            rr.setRemoteRepositories(Collections.singletonList(central));
+            Pair<ArtifactRepository, ArtifactRepository> central = getCentralRepository();
+            rr.setRemoteRepositories(Collections.singletonList(central.getLeft()));
             ArtifactResolutionRequest request = new ArtifactResolutionRequest(rr);
-            for (LicensedProjects lp : mojo.getLicenseMap().values()) {
-                if (lp.getLicense().getDisplayName() != null
-                        && lp.getLicense().getDisplayName().toLowerCase().contains("cddl")) {
-                    ensureCDDLSourcesPointer(lp.getProjects(), central, request);
-                }
+            for (Project cddlProject : cddlProjects) {
+                ensureCDDLSourcesPointer(cddlProject, central.getRight(), request);
             }
         }
     }
 
-    private void ensureCDDLSourcesPointer(Collection<Project> projects, ArtifactRepository central,
+    private void ensureCDDLSourcesPointer(Project project, ArtifactRepository central,
             ArtifactResolutionRequest request) throws ProjectBuildingException, IOException {
-        for (Project p : projects) {
-            if (p.getSourcePointer() != null) {
-                continue;
-            }
-            mojo.getLog().debug("finding sources for artifact: " + p);
-            Artifact sourcesArtifact = new DefaultArtifact(p.getGroupId(), p.getArtifactId(), p.getVersion(),
-                    Artifact.SCOPE_COMPILE, "jar", "sources", null);
-            MavenProject mavenProject = mojo.resolveDependency(sourcesArtifact);
-            sourcesArtifact.setArtifactHandler(mavenProject.getArtifact().getArtifactHandler());
-            final ArtifactRepository localRepo = mojo.getSession().getLocalRepository();
-            final File marker = new File(localRepo.getBasedir(), localRepo.pathOf(sourcesArtifact) + ".oncentral");
-            final File antimarker = new File(localRepo.getBasedir(), localRepo.pathOf(sourcesArtifact) + ".nocentral");
-            boolean onCentral;
-            if (marker.exists() || antimarker.exists()) {
-                onCentral = marker.exists();
-            } else {
-                request.setArtifact(sourcesArtifact);
-                ArtifactResolutionResult result = mojo.getArtifactResolver().resolve(request);
-                mojo.getLog().debug("result: " + result);
-                onCentral = result.isSuccess();
-                if (onCentral) {
-                    FileUtils.touch(marker);
-                } else {
-                    FileUtils.touch(antimarker);
-                }
-            }
-            StringBuilder noticeBuilder = new StringBuilder("You may obtain ");
-            noticeBuilder.append(p.getName()).append(" in Source Code form code here:\n");
-            if (onCentral) {
-                noticeBuilder.append(central.getUrl()).append("/").append(central.pathOf(sourcesArtifact));
-            } else {
-                mojo.getLog().warn("Unable to find sources in 'central' for " + p + ", falling back to project url: "
-                        + p.getUrl());
-                noticeBuilder.append(p.getUrl() != null ? p.getUrl() : "MISSING SOURCE POINTER");
-            }
-            p.setSourcePointer(noticeBuilder.toString());
+        if (project.getSourcePointer() != null) {
+            return;
         }
+        mojo.getLog().debug("finding sources for artifact: " + project);
+        Artifact sourcesArtifact = new DefaultArtifact(project.getGroupId(), project.getArtifactId(),
+                project.getVersion(), Artifact.SCOPE_COMPILE, "jar", "sources", null);
+        MavenProject mavenProject = mojo.resolveDependency(sourcesArtifact);
+        sourcesArtifact.setArtifactHandler(mavenProject.getArtifact().getArtifactHandler());
+        final ArtifactRepository localRepo = mojo.getSession().getLocalRepository();
+        final File marker = new File(localRepo.getBasedir(), localRepo.pathOf(sourcesArtifact) + ".oncentral");
+        final File antimarker = new File(localRepo.getBasedir(), localRepo.pathOf(sourcesArtifact) + ".nocentral");
+        boolean onCentral;
+        if (marker.exists() || antimarker.exists()) {
+            onCentral = marker.exists();
+        } else {
+            request.setArtifact(sourcesArtifact);
+            ArtifactResolutionResult result = mojo.getArtifactResolver().resolve(request);
+            mojo.getLog().debug("result: " + result);
+            onCentral = result.isSuccess();
+            if (onCentral) {
+                FileUtils.touch(marker);
+            } else {
+                FileUtils.touch(antimarker);
+            }
+        }
+        StringBuilder noticeBuilder = new StringBuilder("You may obtain ");
+        noticeBuilder.append(project.getName()).append(" in Source Code form code here:\n");
+        if (onCentral) {
+            noticeBuilder.append(central.getUrl()).append("/").append(central.pathOf(sourcesArtifact));
+        } else {
+            mojo.getLog().warn("Unable to find sources on '" + CENTRAL_REPO_ID + "' for " + project
+                    + ", falling back to project url: " + project.getUrl());
+            noticeBuilder.append(project.getUrl() != null ? project.getUrl() : "MISSING SOURCE POINTER");
+        }
+        project.setSourcePointer(noticeBuilder.toString());
     }
 
     private static class StubArtifactRepository implements ArtifactRepository, AutoCloseable {