Fix for bug#18753 Partitions: auto_increment fails

Current auto increment value is placed in partition in which latest
record was saved. So to get auto_increment they have to scan
all partitions and return max value.

mysql-test/r/partition.result

@@ -839,4 +839,21 @@ SHOW TABLE STATUS;
 Name	Engine	Version	Row_format	Rows	Avg_row_length	Data_length	Max_data_length	Index_length	Data_free	Auto_increment	Create_time	Update_time	Check_time	Collation	Checksum	Create_options	Comment
 t1	MyISAM	10	Dynamic	0	0	0	0	0	0	NULL	NULL	NULL	NULL	latin1_swedish_ci	NULL	partitioned	
 DROP TABLE t1;
+create table t1 (s1 int auto_increment primary key)
+partition by list (s1)
+(partition p1 values in (1),
+partition p2 values in (2),
+partition p3 values in (3));
+insert into t1 values (null);
+insert into t1 values (null);
+insert into t1 values (null);
+select auto_increment from information_schema.tables where table_name='t1';
+auto_increment
+4
+select * from t1;
+s1
+1
+2
+3
+drop table t1;
 End of 5.1 tests

mysql-test/t/partition.test

@@ -956,4 +956,19 @@ PARTITION p2 VALUES LESS THAN (30) ENGINE = MyISAM);
 SHOW TABLE STATUS;
 DROP TABLE t1;
 
+#
+# Bug#18753 Partitions: auto_increment fails
+#
+create table t1 (s1 int auto_increment primary key)
+partition by list (s1)
+(partition p1 values in (1),
+ partition p2 values in (2),
+ partition p3 values in (3));
+insert into t1 values (null);
+insert into t1 values (null);
+insert into t1 values (null);
+select auto_increment from information_schema.tables where table_name='t1';
+select * from t1;
+drop table t1;
+
 --echo End of 5.1 tests

sql/ha_partition.cc

@@ -4201,11 +4201,7 @@ void ha_partition::info(uint flag)
   if (flag & HA_STATUS_AUTO)
   {
     DBUG_PRINT("info", ("HA_STATUS_AUTO"));
-    /*
-      The auto increment value is only maintained by the first handler
-      so we will only call this.
-    */
-    m_file[0]->info(HA_STATUS_AUTO);
+    auto_increment_value= get_auto_increment();
   }
   if (flag & HA_STATUS_VARIABLE)
   {
@@ -5349,9 +5345,15 @@ void ha_partition::restore_auto_increment()
 
 ulonglong ha_partition::get_auto_increment()
 {
+  ulonglong auto_inc, max_auto_inc= 0;
   DBUG_ENTER("ha_partition::get_auto_increment");
 
-  DBUG_RETURN(m_file[0]->get_auto_increment());
+  for (uint i= 0; i < m_tot_parts; i++)
+  {
+    auto_inc= m_file[i]->get_auto_increment();
+    set_if_bigger(max_auto_inc, auto_inc);
+  }
+  DBUG_RETURN(max_auto_inc);
 }