diff --git a/createas.c b/createas.c
index 1a060ae..b6649e5 100644
--- a/createas.c
+++ b/createas.c
@@ -31,6 +31,7 @@
 #include "nodes/nodeFuncs.h"
 #include "nodes/pathnodes.h"
 #include "optimizer/optimizer.h"
+#include "optimizer/prep.h"
 #include "parser/parser.h"
 #include "parser/parsetree.h"
 #include "parser/parse_clause.h"
@@ -1287,9 +1288,6 @@ get_primary_key_attnos_from_query(Query *query, List **constraintList, bool is_c
 	int i;
 	Bitmapset *keys = NULL;
 	Relids	rels_in_from;
-#if defined(PG_VERSION_NUM) && (PG_VERSION_NUM >= 140000)
-	PlannerInfo root;
-#endif
 
 	/*
 	 * Collect primary key attributes from all tables used in query. The key attributes
@@ -1341,28 +1339,25 @@ get_primary_key_attnos_from_query(Query *query, List **constraintList, bool is_c
 		if (IsA(tle->expr, Var))
 		{
 			Var *var = (Var*) tle->expr;
-			Bitmapset *attnos = list_nth(key_attnos_list, var->varno - 1);
+			Bitmapset *key_attnos = list_nth(key_attnos_list, var->varno - 1);
 
 			/* check if this attribute is from a base table's primary key */
-			if (bms_is_member(var->varattno - FirstLowInvalidHeapAttributeNumber, attnos))
+			if (bms_is_member(var->varattno - FirstLowInvalidHeapAttributeNumber, key_attnos))
 			{
 				/*
 				 * Remove found key attributes from key_attnos_list, and add this
 				 * to the result list.
 				 */
-				bms_del_member(attnos, var->varattno - FirstLowInvalidHeapAttributeNumber);
+				bms_del_member(key_attnos, var->varattno - FirstLowInvalidHeapAttributeNumber);
 				keys = bms_add_member(keys, i - FirstLowInvalidHeapAttributeNumber);
 			}
 		}
 		i++;
 	}
 
-	/* Collect relations appearing in the FROM clause */
-#if defined(PG_VERSION_NUM) && (PG_VERSION_NUM >= 140000)
-	rels_in_from = pull_varnos_of_level(&root, (Node *)query->jointree, 0);
-#else
-	rels_in_from = pull_varnos_of_level((Node *)query->jointree, 0);
-#endif
+	/* Collect RTE indexes of relations appearing in the FROM clause */
+	rels_in_from = get_relids_in_jointree((Node *) query->jointree, false);
+
 	/*
 	 * Check if all key attributes of relations in FROM are appearing in the target
 	 * list.  If an attribute remains in key_attnos_list in spite of the table is used
diff --git a/expected/pg_ivm.out b/expected/pg_ivm.out
index 9b62a4f..c329758 100644
--- a/expected/pg_ivm.out
+++ b/expected/pg_ivm.out
@@ -1034,6 +1034,54 @@ drop cascades to table ivm_rls2
 DROP TABLE num_tbl CASCADE;
 DROP USER ivm_user;
 DROP USER ivm_admin;
+-- automatic index creation
+BEGIN;
+CREATE TABLE base_a (i int primary key, j int);
+CREATE TABLE base_b (i int primary key, j int);
+--- group by: create an index
+SELECT create_immv('mv_idx1', 'SELECT i, sum(j) FROM base_a GROUP BY i');
+NOTICE:  created index "mv_idx1_index" on immv "mv_idx1"
+ create_immv 
+-------------
+           0
+(1 row)
+
+--- distinct: create an index
+SELECT create_immv('mv_idx2', 'SELECT DISTINCT j FROM base_a');
+NOTICE:  created index "mv_idx2_index" on immv "mv_idx2"
+ create_immv 
+-------------
+           0
+(1 row)
+
+--- with all pkey columns: create an index
+SELECT create_immv('mv_idx3(i_a, i_b)', 'SELECT a.i, b.i FROM base_a a, base_b b');
+NOTICE:  created index "mv_idx3_index" on immv "mv_idx3"
+ create_immv 
+-------------
+           0
+(1 row)
+
+--- missing some pkey columns: no index
+SELECT create_immv('mv_idx4', 'SELECT j FROM base_a');
+NOTICE:  could not create an index on immv "mv_idx4" automatically
+DETAIL:  This target list does not have all the primary key columns, or this view does not contain GROUP BY or DISTINCT clause.
+HINT:  Create an index on the immv for efficient incremental maintenance.
+ create_immv 
+-------------
+           0
+(1 row)
+
+SELECT create_immv('mv_idx5', 'SELECT a.i, b.j FROM base_a a, base_b b');
+NOTICE:  could not create an index on immv "mv_idx5" automatically
+DETAIL:  This target list does not have all the primary key columns, or this view does not contain GROUP BY or DISTINCT clause.
+HINT:  Create an index on the immv for efficient incremental maintenance.
+ create_immv 
+-------------
+           0
+(1 row)
+
+ROLLBACK;
 -- prevent IMMV chanages
 INSERT INTO mv_ivm_1 VALUES(1,1,1);
 ERROR:  cannot change materialized view "mv_ivm_1"
diff --git a/sql/pg_ivm.sql b/sql/pg_ivm.sql
index 6c6a9f4..5d2dded 100644
--- a/sql/pg_ivm.sql
+++ b/sql/pg_ivm.sql
@@ -454,6 +454,25 @@ DROP TABLE num_tbl CASCADE;
 DROP USER ivm_user;
 DROP USER ivm_admin;
 
+-- automatic index creation
+BEGIN;
+CREATE TABLE base_a (i int primary key, j int);
+CREATE TABLE base_b (i int primary key, j int);
+
+--- group by: create an index
+SELECT create_immv('mv_idx1', 'SELECT i, sum(j) FROM base_a GROUP BY i');
+
+--- distinct: create an index
+SELECT create_immv('mv_idx2', 'SELECT DISTINCT j FROM base_a');
+
+--- with all pkey columns: create an index
+SELECT create_immv('mv_idx3(i_a, i_b)', 'SELECT a.i, b.i FROM base_a a, base_b b');
+
+--- missing some pkey columns: no index
+SELECT create_immv('mv_idx4', 'SELECT j FROM base_a');
+SELECT create_immv('mv_idx5', 'SELECT a.i, b.j FROM base_a a, base_b b');
+ROLLBACK;
+
 -- prevent IMMV chanages
 INSERT INTO mv_ivm_1 VALUES(1,1,1);
 UPDATE  mv_ivm_1 SET k = 1 WHERE i = 1;