MDEV-17676: Assertion `inited==NONE || (inited==RND && scan)' failed …

…in handler::ha_rnd_init

While calculating distinct with the function remove_dup_with_compare, we don't have rnd_end calls
when we have completed the scan over the temporary table.
Added ha_rnd_end calls when we are done with the scan of the table.

mysql-test/r/win.result

@@ -3457,3 +3457,16 @@ i	row_number() over (partition by i order by i)
 deallocate prepare stmt;
 drop table t1;
 drop view v1;
+#
+# MDEV-17676: Assertion `inited==NONE || (inited==RND && scan)' failed in handler::ha_rnd_init
+#
+CREATE TABLE t1 (b1 text NOT NULL);
+INSERT INTO t1 VALUES  ('2'),('1');
+EXPLAIN
+SELECT DISTINCT MIN(b1) OVER () FROM t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	Using temporary
+SELECT DISTINCT MIN(b1) OVER () FROM t1;
+MIN(b1) OVER ()
+1
+drop table t1;

mysql-test/t/win.test

@@ -2216,3 +2216,14 @@ execute stmt;
 deallocate prepare stmt;
 drop table t1;
 drop view v1;
+
+--echo #
+--echo # MDEV-17676: Assertion `inited==NONE || (inited==RND && scan)' failed in handler::ha_rnd_init
+--echo #
+
+CREATE TABLE t1 (b1 text NOT NULL);
+INSERT INTO t1 VALUES  ('2'),('1');
+EXPLAIN
+SELECT DISTINCT MIN(b1) OVER () FROM t1;
+SELECT DISTINCT MIN(b1) OVER () FROM t1;
+drop table t1;

sql/sql_select.cc

@@ -22138,9 +22138,11 @@ static int remove_dup_with_compare(THD *thd, TABLE *table, Field **first_field,
   }
 
   file->extra(HA_EXTRA_NO_CACHE);
+  (void) file->ha_rnd_end();
   DBUG_RETURN(0);
 err:
   file->extra(HA_EXTRA_NO_CACHE);
+  (void) file->ha_rnd_end();
   if (error)
     file->print_error(error,MYF(0));
   DBUG_RETURN(1);