diff --git a/expected/pg_hint_plan.out b/expected/pg_hint_plan.out
index b282bb97..6d9eae85 100644
--- a/expected/pg_hint_plan.out
+++ b/expected/pg_hint_plan.out
@@ -4418,6 +4418,32 @@ error hint:
          Index Cond: (id < 10)
 (7 rows)
 
+-- IndexScan is safe for unordered indexes
+CREATE TABLE ischk (a text, b tsvector) PARTITION BY LIST(a);
+CREATE TABLE ischk_d1 PARTITION OF ischk FOR VALUES IN (0);
+CREATE TABLE ischk_d2 PARTITION OF ischk FOR VALUES IN (1);
+CREATE INDEX ischk_idx ON ischk USING gin (b);
+/*+ IndexScan(ischk ischk_idx) */
+EXPLAIN (COSTS false) SELECT * FROM ischk WHERE b = 'x';
+LOG:  available indexes for IndexScan(ischk_d1): ischk_d1_b_idx
+LOG:  available indexes for IndexScan(ischk_d2): ischk_d2_b_idx
+LOG:  pg_hint_plan:
+used hint:
+IndexScan(ischk ischk_idx)
+not used hint:
+duplication hint:
+error hint:
+
+               QUERY PLAN                
+-----------------------------------------
+ Append
+   ->  Seq Scan on ischk_d1 ischk_1
+         Filter: (b = '''x'''::tsvector)
+   ->  Seq Scan on ischk_d2 ischk_2
+         Filter: (b = '''x'''::tsvector)
+(5 rows)
+
+DROP TABLE ischk;
 -- quote test
 /*+SeqScan("""t1 )	")IndexScan("t	2 """)HashJoin("""t1 )	"T3"t	2 """)Leading("""t1 )	"T3"t	2 """)Set(application_name"a	a	a""	a	A")*/
 EXPLAIN (COSTS false) SELECT * FROM t1 """t1 )	", t2 "t	2 """, t3 "T3" WHERE """t1 )	".id = "t	2 """.id AND """t1 )	".id = "T3".id;
diff --git a/pg_hint_plan.c b/pg_hint_plan.c
index 4ec55fd4..9e71cbdb 100644
--- a/pg_hint_plan.c
+++ b/pg_hint_plan.c
@@ -3583,11 +3583,24 @@ restrict_indexes(PlannerInfo *root, ScanMethodHint *hint, RelOptInfo *rel,
 					/* deny if any of column attributes don't match */
 					if (strcmp(p_attname, c_attname) != 0 ||
 						p_info->indcollation[i] != info->indexcollations[i] ||
-						p_info->opclass[i] != info->opcintype[i]||
-						((p_info->indoption[i] & INDOPTION_DESC) != 0)
-						!= info->reverse_sort[i] ||
-						((p_info->indoption[i] & INDOPTION_NULLS_FIRST) != 0)
-						!= info->nulls_first[i])
+						p_info->opclass[i] != info->opcintype[i])
+						break;
+
+					/*
+					 * Compare index ordering if this index is ordered.
+					 *
+					 * We already confirmed that this and the parent indexes
+					 * share the same column set (actually only the length of
+					 * the column set is compard, though.) and index access
+					 * method. So if this index is unordered, the parent can be
+					 * assumed to be be unodered. Thus no need to bother
+					 * checking the parent's orderedness.
+					 */
+					if (info->sortopfamily != NULL &&
+						(((p_info->indoption[i] & INDOPTION_DESC) != 0)
+						 != info->reverse_sort[i] ||
+						 ((p_info->indoption[i] & INDOPTION_NULLS_FIRST) != 0)
+						 != info->nulls_first[i]))
 						break;
 				}
 
diff --git a/sql/pg_hint_plan.sql b/sql/pg_hint_plan.sql
index 532dd933..619b23d2 100644
--- a/sql/pg_hint_plan.sql
+++ b/sql/pg_hint_plan.sql
@@ -460,6 +460,15 @@ EXPLAIN (COSTS false) SELECT * FROM ONLY p1, t1 WHERE p1.id >= 50 AND p1.id <= 5
 /*+TidScan(p1)*/
 EXPLAIN (COSTS false) SELECT * FROM ONLY p1, t1 WHERE p1.id >= 50 AND p1.id <= 51 AND p1.ctid = '(1,1)' AND p1.id = t1.id AND t1.id < 10;
 
+-- IndexScan is safe for unordered indexes
+CREATE TABLE ischk (a text, b tsvector) PARTITION BY LIST(a);
+CREATE TABLE ischk_d1 PARTITION OF ischk FOR VALUES IN (0);
+CREATE TABLE ischk_d2 PARTITION OF ischk FOR VALUES IN (1);
+CREATE INDEX ischk_idx ON ischk USING gin (b);
+/*+ IndexScan(ischk ischk_idx) */
+EXPLAIN (COSTS false) SELECT * FROM ischk WHERE b = 'x';
+DROP TABLE ischk;
+
 -- quote test
 /*+SeqScan("""t1 )	")IndexScan("t	2 """)HashJoin("""t1 )	"T3"t	2 """)Leading("""t1 )	"T3"t	2 """)Set(application_name"a	a	a""	a	A")*/
 EXPLAIN (COSTS false) SELECT * FROM t1 """t1 )	", t2 "t	2 """, t3 "T3" WHERE """t1 )	".id = "t	2 """.id AND """t1 )	".id = "T3".id;