Fix to ensure that all subpartitions gets deleted before renaming starts, BUG#47029

mysql-test/r/partition_innodb.result

 drop table if exists t1;
+create table t1 (a int not null,
+b datetime not null,
+primary key (a,b))
+engine=innodb
+partition by range (to_days(b))
+subpartition by hash (a)
+subpartitions 2
+( partition p0 values less than (to_days('2009-01-01')),
+partition p1 values less than (to_days('2009-02-01')),
+partition p2 values less than (to_days('2009-03-01')),
+partition p3 values less than maxvalue);
+alter table t1 reorganize partition p1,p2 into
+( partition p2 values less than (to_days('2009-03-01')));
+drop table t1;
 CREATE TABLE t1 (id INT PRIMARY KEY, data INT) ENGINE = InnoDB 
 PARTITION BY RANGE(id) ( 
 PARTITION p0 VALUES LESS THAN (5), 

mysql-test/t/partition_innodb.test

@@ -5,6 +5,23 @@
 drop table if exists t1;
 --enable_warnings
 
+#
+# Bug#47029: Crash when reorganize partition with subpartition
+#
+create table t1 (a int not null,
+                 b datetime not null,
+                 primary key (a,b))
+engine=innodb
+partition by range (to_days(b))
+subpartition by hash (a)
+subpartitions 2
+( partition p0 values less than (to_days('2009-01-01')),
+  partition p1 values less than (to_days('2009-02-01')),
+  partition p2 values less than (to_days('2009-03-01')),
+  partition p3 values less than maxvalue);
+alter table t1 reorganize partition p1,p2 into
+( partition p2 values less than (to_days('2009-03-01')));
+drop table t1;
 #
 # Bug#40595: Non-matching rows not released with READ-COMMITTED on tables
 #            with partitions

sql/ha_partition.cc

@@ -705,6 +705,7 @@ int ha_partition::rename_partitions(const char *path)
       if (m_is_sub_partitioned)
       {
         List_iterator<partition_element> sub_it(part_elem->subpartitions);
+        j= 0;
         do
         {
           sub_elem= sub_it++;