diff --git a/mysql-test/r/func_time.result b/mysql-test/r/func_time.result
index c7db2fc6364..b9533104b76 100644
--- a/mysql-test/r/func_time.result
+++ b/mysql-test/r/func_time.result
@@ -891,6 +891,27 @@ t1	CREATE TABLE `t1` (
   `from_unixtime(1) + 0` double(23,6) default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 DAY)),'%H') As H)
+union
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 DAY)),'%H') As H);
+H
+120
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 DAY)),'%k') As H)
+union
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 DAY)),'%k') As H);
+H
+120
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 HOUR)),'%H') As H)
+union
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 HOUR)),'%H') As H);
+H
+05
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 HOUR)),'%k') As H)
+union
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 HOUR)),'%k') As H);
+H
+5
+End of 4.1 tests
 explain extended select timestampdiff(SQL_TSI_WEEK, '2001-02-01', '2001-05-01') as a1,
 timestampdiff(SQL_TSI_FRAC_SECOND, '2001-02-01 12:59:59.120000', '2001-05-01 12:58:58.119999') as a2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
diff --git a/mysql-test/t/func_time.test b/mysql-test/t/func_time.test
index c95d3e3319a..0945c3ab33e 100644
--- a/mysql-test/t/func_time.test
+++ b/mysql-test/t/func_time.test
@@ -446,7 +446,25 @@ create table t1 select now() - now(), curtime() - curtime(),
 show create table t1;
 drop table t1;
 
-# End of 4.1 tests
+#
+# Bug #19844 time_format in Union truncates values
+#
+
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 DAY)),'%H') As H)
+union
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 DAY)),'%H') As H);
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 DAY)),'%k') As H)
+union
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 DAY)),'%k') As H);
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 HOUR)),'%H') As H)
+union
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 HOUR)),'%H') As H);
+
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 HOUR)),'%k') As H)
+union
+(select time_format(timediff(now(), DATE_SUB(now(),INTERVAL 5 HOUR)),'%k') As H);
+
+--echo End of 4.1 tests
 
 explain extended select timestampdiff(SQL_TSI_WEEK, '2001-02-01', '2001-05-01') as a1,
 			timestampdiff(SQL_TSI_FRAC_SECOND, '2001-02-01 12:59:59.120000', '2001-05-01 12:58:58.119999') as a2;
diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index 835be6554bc..babfdc6a180 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -1704,14 +1704,12 @@ uint Item_func_date_format::format_length(const String *format)
       case 'u': /* week (00..52), where week starts with Monday */
       case 'V': /* week 1..53 used with 'x' */
       case 'v': /* week 1..53 used with 'x', where week starts with Monday */
-      case 'H': /* hour (00..23) */
       case 'y': /* year, numeric, 2 digits */
       case 'm': /* month, numeric */
       case 'd': /* day (of the month), numeric */
       case 'h': /* hour (01..12) */
       case 'I': /* --||-- */
       case 'i': /* minutes, numeric */
-      case 'k': /* hour ( 0..23) */
       case 'l': /* hour ( 1..12) */
       case 'p': /* locale's AM or PM */
       case 'S': /* second (00..61) */
@@ -1720,6 +1718,10 @@ uint Item_func_date_format::format_length(const String *format)
       case 'e': /* day (0..31) */
 	size += 2;
 	break;
+      case 'k': /* hour ( 0..23) */
+      case 'H': /* hour (00..23; value > 23 OK, padding always 2-digit) */
+	size += 7; /* docs allow > 23, range depends on sizeof(unsigned int) */
+	break;
       case 'r': /* time, 12-hour (hh:mm:ss [AP]M) */
 	size += 11;
 	break;
diff --git a/sql/slave.cc b/sql/slave.cc
index 8bcaa6be102..55cff94a179 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -3226,7 +3226,7 @@ static int exec_relay_log_event(THD* thd, RELAY_LOG_INFO* rli)
       rli->is_until_satisfied())
   {
     char buf[22];
-    sql_print_error("Slave SQL thread stopped because it reached its"
+    sql_print_information("Slave SQL thread stopped because it reached its"
                     " UNTIL position %s", llstr(rli->until_pos(), buf));
     /*
       Setting abort_slave flag because we do not want additional message about
diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index 3735f4403de..947eebaa7e8 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -4678,6 +4678,32 @@ int open_grant_tables(THD *thd, TABLE_LIST *tables)
   DBUG_RETURN(0);
 }
 
+ACL_USER *check_acl_user(LEX_USER *user_name,
+			 uint *acl_acl_userdx)
+{
+  ACL_USER *acl_user= 0;
+  uint counter;
+
+  safe_mutex_assert_owner(&acl_cache->lock);
+
+  for (counter= 0 ; counter < acl_users.elements ; counter++)
+  {
+    const char *user,*host;
+    acl_user= dynamic_element(&acl_users, counter, ACL_USER*);
+    if (!(user=acl_user->user))
+      user= "";
+    if (!(host=acl_user->host.hostname))
+      host= "";
+    if (!strcmp(user_name->user.str,user) &&
+	!my_strcasecmp(system_charset_info, user_name->host.str, host))
+      break;
+  }
+  if (counter == acl_users.elements)
+    return 0;
+
+  *acl_acl_userdx= counter;
+  return acl_user;
+}
 
 /*
   Modify a privilege table.
@@ -4701,7 +4727,6 @@ int open_grant_tables(THD *thd, TABLE_LIST *tables)
 
 static int modify_grant_table(TABLE *table, Field *host_field,
                               Field *user_field, LEX_USER *user_to)
-{
   int error;
   DBUG_ENTER("modify_grant_table");
 
@@ -4722,11 +4747,8 @@ static int modify_grant_table(TABLE *table, Field *host_field,
     if ((error=table->file->delete_row(table->record[0])))
       table->file->print_error(error, MYF(0));
   }
-
   DBUG_RETURN(error);
 }
-
-
 /*
   Handle a privilege table.
 
@@ -4815,14 +4837,12 @@ static int handle_grant_table(TABLE_LIST *tables, uint table_no, bool drop,
     DBUG_PRINT("info",("read result: %d", result));
   }
   else
-  {
     /*
       The non-'user' table do not have indexes on (host, user).
       And their host- and user fields are not consecutive.
       Thus, we need to do a table scan to find all matching records.
     */
     if ((error= table->file->ha_rnd_init(1)))
-    {
       table->file->print_error(error, MYF(0));
       result= -1;
     }
@@ -5026,7 +5046,6 @@ static int handle_grant_struct(uint struct_no, bool drop,
         acl_db->user= strdup_root(&mem, user_to->user.str);
         acl_db->host.hostname= strdup_root(&mem, user_to->host.str);
         break;
-
       case 2:
       case 3:
         grant_name->user= strdup_root(&mem, user_to->user.str);
@@ -5036,7 +5055,6 @@ static int handle_grant_struct(uint struct_no, bool drop,
       }
     }
     else
-    {
       /* If search is requested, we do not need to search further. */
       break;
     }
@@ -5044,7 +5062,6 @@ static int handle_grant_struct(uint struct_no, bool drop,
 #ifdef EXTRA_DEBUG
   DBUG_PRINT("loop",("scan struct: %u  result %d", struct_no, result));
 #endif
-
   DBUG_RETURN(result);
 }
 
@@ -5096,7 +5113,6 @@ static int handle_grant_data(TABLE_LIST *tables, bool drop,
       /* If search is requested, we do not need to search further. */
       if (! drop && ! user_to)
         goto end;
-    }
   }
 
   /* Handle db table. */
@@ -5155,10 +5171,8 @@ static int handle_grant_data(TABLE_LIST *tables, bool drop,
 
     /* Handle columns table. */
     if ((found= handle_grant_table(tables, 3, drop, user_from, user_to)) < 0)
-    {
       /* Handle of table failed, don't touch the in-memory array. */
       result= -1;
-    }
     else
     {
       /* Handle columns hash. */
@@ -5206,7 +5220,6 @@ bool mysql_create_user(THD *thd, List <LEX_USER> &list)
   List_iterator <LEX_USER> user_list(list);
   TABLE_LIST tables[GRANT_TABLES];
   DBUG_ENTER("mysql_create_user");
-
   /* CREATE USER may be skipped on replication client. */
   if ((result= open_grant_tables(thd, tables)))
     DBUG_RETURN(result != 1);
@@ -5235,18 +5248,15 @@ bool mysql_create_user(THD *thd, List <LEX_USER> &list)
       for a mention of the new user name.
     */
     if (handle_grant_data(tables, 0, user_name, NULL))
-    {
       append_user(&wrong_users, user_name);
       result= TRUE;
       continue;
     }
-
     sql_mode= thd->variables.sql_mode;
     if (replace_user_table(thd, tables[0].table, *user_name, 0, 0, 1, 0))
     {
       append_user(&wrong_users, user_name);
       result= TRUE;
-    }
   }
 
   VOID(pthread_mutex_unlock(&acl_cache->lock));
@@ -5296,12 +5306,9 @@ bool mysql_drop_user(THD *thd, List <LEX_USER> &list)
       continue;
     }  
     if (handle_grant_data(tables, 1, user_name, NULL) <= 0)
-    {
       append_user(&wrong_users, user_name);
       result= TRUE;
-    }
   }
-
   /* Rebuild 'acl_check_hosts' since 'acl_users' has been modified */
   rebuild_check_host();
 
@@ -5369,14 +5376,16 @@ bool mysql_rename_user(THD *thd, List <LEX_USER> &list)
       append_user(&wrong_users, user_from);
       result= TRUE;
     }
-  }
 
   /* Rebuild 'acl_check_hosts' since 'acl_users' has been modified */
   rebuild_check_host();
 
+
   VOID(pthread_mutex_unlock(&acl_cache->lock));
   rw_unlock(&LOCK_grant);
   close_thread_tables(thd);
+  if (result)
+    my_error(ER_CANNOT_USER, MYF(0), "RENAME USER", wrong_users.c_ptr_safe());
   if (result)
     my_error(ER_CANNOT_USER, MYF(0), "RENAME USER", wrong_users.c_ptr_safe());
   DBUG_RETURN(result);