diff --git a/mysql-test/r/select.result b/mysql-test/r/select.result
index 0c62d3f570f..350a05a13c8 100644
--- a/mysql-test/r/select.result
+++ b/mysql-test/r/select.result
@@ -3517,3 +3517,9 @@ id	a	b	c	d	e
 2	NULL	NULL	NULL	2	40
 2	NULL	NULL	NULL	2	50
 DROP TABLE t1,t2,t3;
+create table t1 (c1 varchar(1), c2 int, c3 int, c4 int, c5 int, c6 int,
+c7 int, c8 int, c9 int, fulltext key (`c1`));
+select distinct match (`c1`) against ('z') , c2, c3, c4,c5, c6,c7, c8 
+from t1 where c9=1 order by c2, c2;
+match (`c1`) against ('z')	c2	c3	c4	c5	c6	c7	c8
+drop table t1;
diff --git a/mysql-test/t/select.test b/mysql-test/t/select.test
index 36b3749b4d7..0686f670edf 100644
--- a/mysql-test/t/select.test
+++ b/mysql-test/t/select.test
@@ -2996,5 +2996,14 @@ SELECT * FROM t1 LEFT JOIN t2 ON t2.b=t1.a INNER JOIN t3 ON t3.d=t1.id
 SELECT * FROM t1 LEFT JOIN t2 ON t2.b=t1.a INNER JOIN t3 ON t3.d=t1.id
   WHERE t1.id=2;
 
-
 DROP TABLE t1,t2,t3;
+
+#
+# Bug#20503: Server crash due to the ORDER clause isn't taken into account
+#            while space allocation
+#
+create table t1 (c1 varchar(1), c2 int, c3 int, c4 int, c5 int, c6 int,
+c7 int, c8 int, c9 int, fulltext key (`c1`));
+select distinct match (`c1`) against ('z') , c2, c3, c4,c5, c6,c7, c8 
+  from t1 where c9=1 order by c2, c2;
+drop table t1;
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index b328d9162d5..b814bd1d565 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -13513,7 +13513,19 @@ bool JOIN::alloc_func_list()
     disctinct->group_by optimization
   */
   if (select_distinct)
+  {
     group_parts+= fields_list.elements;
+    /*
+      If the ORDER clause is specified then it's possible that
+      it also will be optimized, so reserve space for it too
+    */
+    if (order)
+    {
+      ORDER *ord;
+      for (ord= order; ord; ord= ord->next)
+        group_parts++;
+    }
+  }
 
   /* This must use calloc() as rollup_make_fields depends on this */
   sum_funcs= (Item_sum**) thd->calloc(sizeof(Item_sum**) * (func_count+1) +