Merge gkodinov@bk-internal.mysql.com:/home/bk/mysql-5.1-opt

into  magare.gmz:/home/kgeorge/mysql/autopush/WL3527-5.1-opt


BitKeeper/deleted/.del-sql_parse.cc.rej:
  Auto merged
BitKeeper/deleted/.del-table.cc.rej:
  Auto merged
mysql-test/r/endspace.result:
  Auto merged
mysql-test/t/group_by.test:
  Auto merged
sql/item.cc:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/opt_range.cc:
  Auto merged
sql/sql_class.h:
  Auto merged
sql/sql_delete.cc:
  Auto merged
sql/sql_help.cc:
  Auto merged
sql/sql_lex.cc:
  Auto merged
sql/sql_lex.h:
  Auto merged
sql/sql_parse.cc:
  Auto merged
sql/sql_show.cc:
  Auto merged
sql/sql_update.cc:
  Auto merged
sql/sql_yacc.yy:
  Auto merged
sql/table.cc:
  Auto merged
storage/myisam/ha_myisam.cc:
  Auto merged
BitKeeper/deleted/.del-mysqld.cc.rej~35c1c438e11ebd89:
  Auto merged
mysql-test/r/group_by.result:
  manual merge to 5.1-opt
sql/mysqld.cc:
  manual merge to 5.1-opt
sql/sql_base.cc:
  manual merge to 5.1-opt
sql/sql_select.cc:
  manual merge to 5.1-opt
sql/table.h:
  manual merge to 5.1-opt

22 files changed, 724 insertions, 262 deletions

diff --git a/mysql-test/r/endspace.result b/mysql-test/r/endspace.result
index 003ee7ffd5e..6fb33dee826 100644
--- a/mysql-test/r/endspace.result
+++ b/mysql-test/r/endspace.result
@@ -25,10 +25,11 @@ insert into t1 values ('teststring'), ('nothing'), ('teststring\t');
 check table t1;
 Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
-select * from t1 ignore key (key1) where text1='teststring' or text1 like 'teststring_%';
+select * from t1 ignore key (key1) where text1='teststring' or 
+text1 like 'teststring_%' ORDER BY text1;
 text1
-teststring
 teststring	
+teststring
 select * from t1 where text1='teststring' or text1 like 'teststring_%';
 text1
 teststring	
@@ -48,10 +49,11 @@ alter table t1 modify text1 char(32) binary not null;
 check table t1;
 Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
-select * from t1 ignore key (key1) where text1='teststring' or text1 like 'teststring_%';
+select * from t1 ignore key (key1) where text1='teststring' or 
+text1 like 'teststring_%' ORDER BY text1;
 text1
-teststring
 teststring	
+teststring
 select concat('|', text1, '|') from t1 where text1='teststring' or text1 like 'teststring_%';
 concat('|', text1, '|')
 |teststring	|
@@ -132,10 +134,11 @@ concat('|', text1, '|')
 drop table t1;
 create table t1 (text1 varchar(32) not NULL, KEY key1 using BTREE (text1)) engine=heap;
 insert into t1 values ('teststring'), ('nothing'), ('teststring\t');
-select * from t1 ignore key (key1) where text1='teststring' or text1 like 'teststring_%';
+select * from t1 ignore key (key1) where text1='teststring' or 
+text1 like 'teststring_%' ORDER BY text1;
 text1
-teststring
 teststring	
+teststring
 select * from t1 where text1='teststring' or text1 like 'teststring_%';
 text1
 teststring	
diff --git a/mysql-test/r/group_by.result b/mysql-test/r/group_by.result
index d583eb02aeb..ae61dfb252d 100644
--- a/mysql-test/r/group_by.result
+++ b/mysql-test/r/group_by.result
@@ -1035,12 +1035,110 @@ HAVING SUM(t1_inner.b)+t1_outer.b > 5);
 ERROR 42000: 'test.t1_outer.b' isn't in GROUP BY
 DROP TABLE t1;
 SET SQL_MODE = '';
-CREATE TABLE t1 (a INT, b INT, KEY(a));
-INSERT INTO t1 VALUES (1, 1), (2, 2), (3,3), (4,4);
-EXPLAIN SELECT a, SUM(b) FROM t1 GROUP BY a LIMIT 2;
+CREATE TABLE t1 (a INT, b INT,
+PRIMARY KEY (a),
+KEY i2(a,b));
+INSERT INTO t1 VALUES (1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8);
+INSERT INTO t1 SELECT a + 8,b FROM t1;
+INSERT INTO t1 SELECT a + 16,b FROM t1;
+INSERT INTO t1 SELECT a + 32,b FROM t1;
+INSERT INTO t1 SELECT a + 64,b FROM t1;
+INSERT INTO t1 SELECT a + 128,b FROM t1;
+ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	OK
+EXPLAIN SELECT a FROM t1 WHERE a < 2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index	NULL	a	5	NULL	4	
-EXPLAIN SELECT a, SUM(b) FROM t1 IGNORE INDEX (a) GROUP BY a LIMIT 2;
+1	SIMPLE	t1	range	PRIMARY,i2	PRIMARY	4	NULL	2	Using where; Using index
+EXPLAIN SELECT a FROM t1 WHERE a < 2 ORDER BY a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using temporary; Using filesort
-DROP TABLE t1;
+1	SIMPLE	t1	range	PRIMARY,i2	PRIMARY	4	NULL	2	Using where; Using index
+EXPLAIN SELECT a FROM t1 WHERE a < 2 GROUP BY a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	PRIMARY,i2	PRIMARY	4	NULL	2	Using where; Using index
+EXPLAIN SELECT a FROM t1 IGNORE INDEX (PRIMARY,i2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	256	
+EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR JOIN (PRIMARY,i2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	256	
+EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR GROUP BY (PRIMARY,i2) GROUP BY a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	256	Using index
+EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR ORDER BY (PRIMARY,i2) ORDER BY a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	256	Using index
+EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR ORDER BY (PRIMARY)
+IGNORE INDEX FOR GROUP BY (i2) GROUP BY a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	256	Using index
+EXPLAIN SELECT a FROM t1 IGNORE INDEX (PRIMARY) IGNORE INDEX FOR ORDER BY (i2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	i2	9	NULL	256	Using index
+EXPLAIN SELECT a FROM t1 FORCE INDEX (i2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	i2	9	NULL	256	Using index
+EXPLAIN SELECT a FROM t1 USE INDEX ();
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	256	
+EXPLAIN SELECT a FROM t1 USE INDEX () USE INDEX (i2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	256	
+EXPLAIN SELECT a FROM t1 
+FORCE INDEX (PRIMARY) 
+IGNORE INDEX FOR GROUP BY (i2)
+IGNORE INDEX FOR ORDER BY (i2)
+USE INDEX (i2);
+ERROR HY000: Incorrect usage of USE INDEX and FORCE INDEX
+EXPLAIN SELECT a FROM t1 USE INDEX (i2) USE INDEX ();
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	i2	9	NULL	256	Using index
+EXPLAIN SELECT a FROM t1 FORCE INDEX ();
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1
+EXPLAIN SELECT a FROM t1 IGNORE INDEX ();
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1
+EXPLAIN SELECT a FROM t1 USE INDEX FOR JOIN (i2) 
+USE INDEX FOR GROUP BY (i2) GROUP BY a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	i2	9	NULL	256	Using index
+EXPLAIN SELECT a FROM t1 FORCE INDEX FOR JOIN (i2) 
+FORCE INDEX FOR GROUP BY (i2) GROUP BY a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	NULL	i2	4	NULL	257	Using index for group-by
+EXPLAIN SELECT a FROM t1 USE INDEX () IGNORE INDEX (i2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	256	
+EXPLAIN SELECT a FROM t1 IGNORE INDEX (i2) USE INDEX ();
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	256	
+EXPLAIN SELECT a FROM t1 
+USE INDEX FOR GROUP BY (i2) 
+USE INDEX FOR ORDER BY (i2)
+USE INDEX FOR JOIN (i2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	i2	9	NULL	256	Using index
+EXPLAIN SELECT a FROM t1 
+USE INDEX FOR JOIN (i2) 
+USE INDEX FOR JOIN (i2) 
+USE INDEX FOR JOIN (i2,i2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	i2	9	NULL	256	Using index
+EXPLAIN SELECT 1 FROM t1 WHERE a IN
+(SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	NULL	PRIMARY	4	NULL	256	Using where; Using index
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	256	Using where
+CREATE TABLE t2 (a INT, b INT, KEY(a));
+INSERT INTO t2 VALUES (1, 1), (2, 2), (3,3), (4,4);
+EXPLAIN SELECT a, SUM(b) FROM t2 GROUP BY a LIMIT 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	NULL	a	5	NULL	4	
+EXPLAIN SELECT a, SUM(b) FROM t2 IGNORE INDEX (a) GROUP BY a LIMIT 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	4	Using temporary; Using filesort
+EXPLAIN SELECT 1 FROM t2 WHERE a IN
+(SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	index	NULL	a	5	NULL	4	Using where; Using index
+2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	256	Using where
+DROP TABLE t1, t2;
diff --git a/mysql-test/t/endspace.test b/mysql-test/t/endspace.test
index c4d53450910..b223c683cde 100644
--- a/mysql-test/t/endspace.test
+++ b/mysql-test/t/endspace.test
@@ -16,7 +16,8 @@ drop table if exists t1;
 create table t1 (text1 varchar(32) not NULL, KEY key1 (text1));
 insert into t1 values ('teststring'), ('nothing'), ('teststring\t');
 check table t1;
-select * from t1 ignore key (key1) where text1='teststring' or text1 like 'teststring_%';
+select * from t1 ignore key (key1) where text1='teststring' or 
+  text1 like 'teststring_%' ORDER BY text1;
 select * from t1 where text1='teststring' or text1 like 'teststring_%';
 select * from t1 where text1='teststring' or text1 > 'teststring\t';
 select * from t1 order by text1;
@@ -24,7 +25,8 @@ explain select * from t1 order by text1;
 
 alter table t1 modify text1 char(32) binary not null;
 check table t1;
-select * from t1 ignore key (key1) where text1='teststring' or text1 like 'teststring_%';
+select * from t1 ignore key (key1) where text1='teststring' or 
+  text1 like 'teststring_%' ORDER BY text1;
 select concat('|', text1, '|') from t1 where text1='teststring' or text1 like 'teststring_%';
 select concat('|', text1, '|') from t1 where text1='teststring' or text1 > 'teststring\t';
 select text1, length(text1) from t1 order by text1;
@@ -57,7 +59,8 @@ drop table t1;
 
 create table t1 (text1 varchar(32) not NULL, KEY key1 using BTREE (text1)) engine=heap;
 insert into t1 values ('teststring'), ('nothing'), ('teststring\t');
-select * from t1 ignore key (key1) where text1='teststring' or text1 like 'teststring_%';
+select * from t1 ignore key (key1) where text1='teststring' or 
+  text1 like 'teststring_%' ORDER BY text1;
 select * from t1 where text1='teststring' or text1 like 'teststring_%';
 select * from t1 where text1='teststring' or text1 >= 'teststring\t';
 select * from t1 order by text1;
diff --git a/mysql-test/t/group_by.test b/mysql-test/t/group_by.test
index 76e4af8f610..a3318745764 100644
--- a/mysql-test/t/group_by.test
+++ b/mysql-test/t/group_by.test
@@ -757,10 +757,66 @@ SET SQL_MODE = '';
 # Bug #21174: Index degrades sort performance and 
 #             optimizer does not honor IGNORE INDEX
 #
-CREATE TABLE t1 (a INT, b INT, KEY(a));
-INSERT INTO t1 VALUES (1, 1), (2, 2), (3,3), (4,4);
+CREATE TABLE t1 (a INT, b INT,
+                 PRIMARY KEY (a),
+                 KEY i2(a,b));
+INSERT INTO t1 VALUES (1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8);
+INSERT INTO t1 SELECT a + 8,b FROM t1;
+INSERT INTO t1 SELECT a + 16,b FROM t1;
+INSERT INTO t1 SELECT a + 32,b FROM t1;
+INSERT INTO t1 SELECT a + 64,b FROM t1;
+INSERT INTO t1 SELECT a + 128,b FROM t1;
+ANALYZE TABLE t1;
+EXPLAIN SELECT a FROM t1 WHERE a < 2;
+EXPLAIN SELECT a FROM t1 WHERE a < 2 ORDER BY a;
+EXPLAIN SELECT a FROM t1 WHERE a < 2 GROUP BY a;
+EXPLAIN SELECT a FROM t1 IGNORE INDEX (PRIMARY,i2);
+EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR JOIN (PRIMARY,i2);
+EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR GROUP BY (PRIMARY,i2) GROUP BY a;
+EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR ORDER BY (PRIMARY,i2) ORDER BY a;
+EXPLAIN SELECT a FROM t1 IGNORE INDEX FOR ORDER BY (PRIMARY)
+  IGNORE INDEX FOR GROUP BY (i2) GROUP BY a;
+EXPLAIN SELECT a FROM t1 IGNORE INDEX (PRIMARY) IGNORE INDEX FOR ORDER BY (i2);
+EXPLAIN SELECT a FROM t1 FORCE INDEX (i2);
+EXPLAIN SELECT a FROM t1 USE INDEX ();
+EXPLAIN SELECT a FROM t1 USE INDEX () USE INDEX (i2);
+--error ER_WRONG_USAGE
+EXPLAIN SELECT a FROM t1 
+  FORCE INDEX (PRIMARY) 
+  IGNORE INDEX FOR GROUP BY (i2)
+  IGNORE INDEX FOR ORDER BY (i2)
+  USE INDEX (i2);
+EXPLAIN SELECT a FROM t1 USE INDEX (i2) USE INDEX ();
+--error ER_PARSE_ERROR
+EXPLAIN SELECT a FROM t1 FORCE INDEX ();
+--error ER_PARSE_ERROR
+EXPLAIN SELECT a FROM t1 IGNORE INDEX ();
+EXPLAIN SELECT a FROM t1 USE INDEX FOR JOIN (i2) 
+  USE INDEX FOR GROUP BY (i2) GROUP BY a;
+EXPLAIN SELECT a FROM t1 FORCE INDEX FOR JOIN (i2) 
+  FORCE INDEX FOR GROUP BY (i2) GROUP BY a;
+EXPLAIN SELECT a FROM t1 USE INDEX () IGNORE INDEX (i2);
+EXPLAIN SELECT a FROM t1 IGNORE INDEX (i2) USE INDEX ();
+
+EXPLAIN SELECT a FROM t1 
+  USE INDEX FOR GROUP BY (i2) 
+  USE INDEX FOR ORDER BY (i2)
+  USE INDEX FOR JOIN (i2);
+
+EXPLAIN SELECT a FROM t1 
+  USE INDEX FOR JOIN (i2) 
+  USE INDEX FOR JOIN (i2) 
+  USE INDEX FOR JOIN (i2,i2);
+
+EXPLAIN SELECT 1 FROM t1 WHERE a IN
+  (SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
+
+CREATE TABLE t2 (a INT, b INT, KEY(a));
+INSERT INTO t2 VALUES (1, 1), (2, 2), (3,3), (4,4);
+EXPLAIN SELECT a, SUM(b) FROM t2 GROUP BY a LIMIT 2; 
+EXPLAIN SELECT a, SUM(b) FROM t2 IGNORE INDEX (a) GROUP BY a LIMIT 2;
+
+EXPLAIN SELECT 1 FROM t2 WHERE a IN
+  (SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
 
-EXPLAIN SELECT a, SUM(b) FROM t1 GROUP BY a LIMIT 2; 
-EXPLAIN SELECT a, SUM(b) FROM t1 IGNORE INDEX (a) GROUP BY a LIMIT 2;
-
-DROP TABLE t1;
+DROP TABLE t1, t2;
diff --git a/sql/item.cc b/sql/item.cc
index 19f5c215274..c423f17f52b 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -3906,7 +3906,7 @@ bool Item_field::fix_fields(THD *thd, Item **reference)
       {
         /* First usage of column */
         table->used_fields++;                     // Used to optimize loops
-        table->used_keys.intersect(field->part_of_key);
+        table->covering_keys.intersect(field->part_of_key);
       }
     }
   }
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index efcbdf968bf..e339dfa3df4 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -2021,7 +2021,6 @@ inline void setup_table_map(TABLE *table, TABLE_LIST *table_list, uint tablenr)
   table->const_table= 0;
   table->null_row= 0;
   table->status= STATUS_NO_RECORD;
-  table->keys_in_use_for_query= table->s->keys_in_use;
   table->maybe_null= table_list->outer_join;
   TABLE_LIST *embedding= table_list->embedding;
   while (!table->maybe_null && embedding)
@@ -2032,6 +2031,8 @@ inline void setup_table_map(TABLE *table, TABLE_LIST *table_list, uint tablenr)
   table->tablenr= tablenr;
   table->map= (table_map) 1 << tablenr;
   table->force_index= table_list->force_index;
+  table->covering_keys= table->s->keys_for_keyread;
+  table->merge_keys.clear_all();
 }
 
 
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 758dc54316e..22ba049f1a5 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -5025,7 +5025,8 @@ enum options_mysqld
   OPT_MERGE,
   OPT_THREAD_HANDLING,
   OPT_INNODB_ROLLBACK_ON_TIMEOUT,
-  OPT_SECURE_FILE_PRIV
+  OPT_SECURE_FILE_PRIV,
+  OPT_OLD_MODE
 };
 
 
@@ -6256,6 +6257,10 @@ The minimum value for this variable is 4096.",
    (gptr*) &global_system_variables.net_write_timeout,
    (gptr*) &max_system_variables.net_write_timeout, 0, GET_ULONG,
    REQUIRED_ARG, NET_WRITE_TIMEOUT, 1, LONG_TIMEOUT, 0, 1, 0},
+  { "old_mode", OPT_OLD_MODE, "Use compatible behaviour.", 
+    (gptr*) &global_system_variables.old_mode,
+    (gptr*) &max_system_variables.old_mode, 0, GET_BOOL, NO_ARG, 
+    0, 0, 0, 0, 0, 0},
   {"open_files_limit", OPT_OPEN_FILES_LIMIT,
    "If this is not 0, then mysqld will use this value to reserve file descriptors to use with setrlimit(). If this value is 0 then mysqld will reserve max_connections*5 or max_connections + table_cache*2 (whichever is larger) number of files.",
    (gptr*) &open_files_limit, (gptr*) &open_files_limit, 0, GET_ULONG,
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 3dc780e1b5f..d43b2522e41 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -2111,9 +2111,9 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
     param.key_parts_end=key_parts;
 
     /* Calculate cost of full index read for the shortest covering index */
-    if (!head->used_keys.is_clear_all())
+    if (!head->covering_keys.is_clear_all())
     {
-      int key_for_use= find_shortest_key(head, &head->used_keys);
+      int key_for_use= find_shortest_key(head, &head->covering_keys);
       double key_read_time= (get_index_only_read_time(&param, records,
                                                      key_for_use) +
                              (double) records / TIME_FOR_COMPARE);
@@ -4646,7 +4646,7 @@ static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
         param->needed_reg->set_bit(keynr);
 
       bool read_index_only= index_read_must_be_used ? TRUE :
-                            (bool) param->table->used_keys.is_set(keynr);
+                            (bool) param->table->covering_keys.is_set(keynr);
 
       found_records= check_quick_select(param, idx, *key, update_tbl_stats);
       if (param->is_ror_scan)
@@ -9012,7 +9012,7 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree)
        cur_index_info++, cur_index++)
   {
     /* Check (B1) - if current index is covering. */
-    if (!table->used_keys.is_set(cur_index))
+    if (!table->covering_keys.is_set(cur_index))
       goto next_index;
 
     /*
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index e764c498059..d4316f11491 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -1851,8 +1851,6 @@ bool reopen_name_locked_table(THD* thd, TABLE_LIST* table_list)
   table->const_table=0;
   table->null_row= table->maybe_null= table->force_index= 0;
   table->status=STATUS_NO_RECORD;
-  table->keys_in_use_for_query= share->keys_in_use;
-  table->used_keys= share->keys_for_keyread;
   DBUG_RETURN(FALSE);
 }
 
@@ -2271,9 +2269,7 @@ TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT *mem_root,
   table->const_table=0;
   table->null_row= table->maybe_null= table->force_index= 0;
   table->status=STATUS_NO_RECORD;
-  table->keys_in_use_for_query= table->s->keys_in_use;
   table->insert_values= 0;
-  table->used_keys= table->s->keys_for_keyread;
   table->fulltext_searched= 0;
   table->file->ft_handler= 0;
   if (table->timestamp_field)
@@ -2358,8 +2354,6 @@ static bool reopen_table(TABLE *table)
   tmp.null_row=		table->null_row;
   tmp.maybe_null=	table->maybe_null;
   tmp.status=		table->status;
-  tmp.keys_in_use_for_query= tmp.s->keys_in_use;
-  tmp.used_keys= 	tmp.s->keys_for_keyread;
 
   tmp.s->table_map_id=  table->s->table_map_id;
 
@@ -3820,7 +3814,7 @@ static void update_field_dependencies(THD *thd, Field *field, TABLE *table)
       been set for all fields (for example for view).
     */
       
-    table->used_keys.intersect(field->part_of_key);
+    table->covering_keys.intersect(field->part_of_key);
     table->merge_keys.merge(field->part_of_key);
 
     if (thd->mark_used_columns == MARK_COLUMNS_READ)
@@ -5060,7 +5054,7 @@ mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2,
         TABLE *table_1= nj_col_1->table_ref->table;
         /* Mark field_1 used for table cache. */
         bitmap_set_bit(table_1->read_set, field_1->field_index);
-        table_1->used_keys.intersect(field_1->part_of_key);
+        table_1->covering_keys.intersect(field_1->part_of_key);
         table_1->merge_keys.merge(field_1->part_of_key);
       }
       if (field_2)
@@ -5068,7 +5062,7 @@ mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2,
         TABLE *table_2= nj_col_2->table_ref->table;
         /* Mark field_2 used for table cache. */
         bitmap_set_bit(table_2->read_set, field_2->field_index);
-        table_2->used_keys.intersect(field_2->part_of_key);
+        table_2->covering_keys.intersect(field_2->part_of_key);
         table_2->merge_keys.merge(field_2->part_of_key);
       }
 
@@ -5704,30 +5698,8 @@ bool setup_tables(THD *thd, Name_resolution_context *context,
       tablenr= 0;
     }
     setup_table_map(table, table_list, tablenr);
-    table->used_keys= table->s->keys_for_keyread;
-    table->merge_keys.clear_all();
-    if (table_list->use_index)
-    {
-      key_map map;
-      get_key_map_from_key_list(&map, table, table_list->use_index);
-      if (map.is_set_all())
-	DBUG_RETURN(1);
-      /* 
-	 Don't introduce keys in keys_in_use_for_query that weren't there 
-	 before. FORCE/USE INDEX should not add keys, it should only remove
-	 all keys except the key(s) specified in the hint.
-      */
-      table->keys_in_use_for_query.intersect(map);
-    }
-    if (table_list->ignore_index)
-    {
-      key_map map;
-      get_key_map_from_key_list(&map, table, table_list->ignore_index);
-      if (map.is_set_all())
-	DBUG_RETURN(1);
-      table->keys_in_use_for_query.subtract(map);
-    }
-    table->used_keys.intersect(table->keys_in_use_for_query);
+    if (table_list->process_index_hints(table))
+      DBUG_RETURN(1);
   }
   if (tablenr > MAX_TABLES)
   {
@@ -6009,7 +5981,7 @@ insert_fields(THD *thd, Name_resolution_context *context, const char *db_name,
         bitmap_set_bit(field->table->read_set, field->field_index);
         if (table)
         {
-          table->used_keys.intersect(field->part_of_key);
+          table->covering_keys.intersect(field->part_of_key);
           table->merge_keys.merge(field->part_of_key);
         }
         if (tables->is_natural_join)
@@ -6027,7 +5999,7 @@ insert_fields(THD *thd, Name_resolution_context *context, const char *db_name,
           if (field_table)
           {
             thd->used_tables|= field_table->map;
-            field_table->used_keys.intersect(field->part_of_key);
+            field_table->covering_keys.intersect(field->part_of_key);
             field_table->merge_keys.merge(field->part_of_key);
             field_table->used_fields++;
           }
diff --git a/sql/sql_class.h b/sql/sql_class.h
index ffc8b2c46d1..de166a68833 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -243,6 +243,11 @@ struct system_variables
 
   my_bool low_priority_updates;
   my_bool new_mode;
+  /* 
+    compatibility option:
+      - index usage hints (USE INDEX without a FOR clause) behave as in 5.0 
+  */
+  my_bool old_mode;
   my_bool query_cache_wlock_invalidate;
   my_bool engine_condition_pushdown;
   my_bool innodb_table_locks;
@@ -278,6 +283,7 @@ struct system_variables
   DATE_TIME_FORMAT *datetime_format;
   DATE_TIME_FORMAT *time_format;
   my_bool sysdate_is_now;
+
 };
 
 
diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc
index 07313c954ba..0ff5c4e5b50 100644
--- a/sql/sql_delete.cc
+++ b/sql/sql_delete.cc
@@ -116,7 +116,7 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
   /* Update the table->file->stats.records number */
   table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
 
-  table->used_keys.clear_all();
+  table->covering_keys.clear_all();
   table->quick_keys.clear_all();		// Can't use 'only index'
   select=make_select(table, 0, 0, conds, 0, &error);
   if (error)
@@ -553,7 +553,7 @@ multi_delete::initialize_tables(JOIN *join)
       tbl->no_keyread=1;
       /* Don't use record cache */
       tbl->no_cache= 1;
-      tbl->used_keys.clear_all();
+      tbl->covering_keys.clear_all();
       if (tbl->file->has_transactions())
 	transactional_tables= 1;
       else
diff --git a/sql/sql_help.cc b/sql/sql_help.cc
index b8a904b0c6e..6cb87c7e601 100644
--- a/sql/sql_help.cc
+++ b/sql/sql_help.cc
@@ -567,7 +567,7 @@ SQL_SELECT *prepare_simple_select(THD *thd, Item *cond,
     cond->fix_fields(thd, &cond);	// can never fail
 
   /* Assume that no indexes cover all required fields */
-  table->used_keys.clear_all();
+  table->covering_keys.clear_all();
 
   SQL_SELECT *res= make_select(table, 0, 0, cond, 0, error);
   if (*error || (res && res->check_quick(thd, 0, HA_POS_ERROR)) ||
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 389e7b5fd7a..06bb2ea0f81 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -69,6 +69,17 @@ static uchar to_upper_lex[]=
   208,209,210,211,212,213,214,247,216,217,218,219,220,221,222,255
 };
 
+/* 
+  Names of the index hints (for error messages). Keep in sync with 
+  index_hint_type 
+*/
+
+const char * index_hint_type_name[] =
+{
+  "IGNORE INDEX", 
+  "USE INDEX", 
+  "FORCE INDEX"
+};
 
 inline int lex_casecmp(const char *s, const char *t, uint len)
 {
@@ -1201,7 +1212,6 @@ void st_select_lex::init_select()
   group_list.empty();
   type= db= 0;
   having= 0;
-  use_index_ptr= ignore_index_ptr= 0;
   table_join_options= 0;
   in_sum_expr= with_wild= 0;
   options= 0;
@@ -1209,7 +1219,6 @@ void st_select_lex::init_select()
   braces= 0;
   expr_list.empty();
   interval_list.empty();
-  use_index.empty();
   ftfunc_list_alloc.empty();
   inner_sum_func_list= 0;
   ftfunc_list= &ftfunc_list_alloc;
@@ -1436,14 +1445,11 @@ bool st_select_lex_node::inc_in_sum_expr()           { return 1; }
 uint st_select_lex_node::get_in_sum_expr()           { return 0; }
 TABLE_LIST* st_select_lex_node::get_table_list()     { return 0; }
 List<Item>* st_select_lex_node::get_item_list()      { return 0; }
-List<String>* st_select_lex_node::get_use_index()    { return 0; }
-List<String>* st_select_lex_node::get_ignore_index() { return 0; }
-TABLE_LIST *st_select_lex_node::add_table_to_list(THD *thd, Table_ident *table,
+TABLE_LIST *st_select_lex_node::add_table_to_list (THD *thd, Table_ident *table,
 						  LEX_STRING *alias,
 						  ulong table_join_options,
 						  thr_lock_type flags,
-						  List<String> *use_index,
-						  List<String> *ignore_index,
+						  List<index_hint> *hints,
                                                   LEX_STRING *option)
 {
   return 0;
@@ -1550,19 +1556,6 @@ List<Item>* st_select_lex::get_item_list()
   return &item_list;
 }
 
-
-List<String>* st_select_lex::get_use_index()
-{
-  return use_index_ptr;
-}
-
-
-List<String>* st_select_lex::get_ignore_index()
-{
-  return ignore_index_ptr;
-}
-
-
 ulong st_select_lex::get_table_join_options()
 {
   return table_join_options;
@@ -2328,3 +2321,61 @@ void st_select_lex::fix_prepare_information(THD *thd, Item **conds,
   are in sql_union.cc
 */
 
+/*
+  Sets the kind of hints to be added by the calls to add_index_hint().
+
+  SYNOPSIS
+    set_index_hint_type()
+      type         the kind of hints to be added from now on.
+      clause       the clause to use for hints to be added from now on.
+
+  DESCRIPTION
+    Used in filling up the tagged hints list.
+    This list is filled by first setting the kind of the hint as a 
+    context variable and then adding hints of the current kind.
+    Then the context variable index_hint_type can be reset to the
+    next hint type.
+*/
+void st_select_lex::set_index_hint_type(enum index_hint_type type, 
+                                        index_clause_map clause)
+{ 
+  current_index_hint_type= type;
+  current_index_hint_clause= clause;
+}
+
+
+/*
+  Makes an array to store index usage hints (ADD/FORCE/IGNORE INDEX).
+
+  SYNOPSIS
+    alloc_index_hints()
+      thd         current thread.
+*/
+
+void st_select_lex::alloc_index_hints (THD *thd)
+{ 
+  index_hints= new (thd->mem_root) List<index_hint>(); 
+}
+
+
+
+/*
+  adds an element to the array storing index usage hints 
+  (ADD/FORCE/IGNORE INDEX).
+
+  SYNOPSIS
+    add_index_hint()
+      thd         current thread.
+      str         name of the index.
+      length      number of characters in str.
+
+  RETURN VALUE
+    0 on success, non-zero otherwise
+*/
+bool st_select_lex::add_index_hint (THD *thd, char *str, uint length)
+{
+  return index_hints->push_front (new (thd->mem_root) 
+                                 index_hint(current_index_hint_type,
+                                            current_index_hint_clause,
+                                            str, length));
+}
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 1271df5e458..fcdc00a0e39 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -217,6 +217,47 @@ enum tablespace_op_type
 };
 
 /* 
+  String names used to print a statement with index hints.
+  Keep in sync with index_hint_type.
+*/
+extern const char * index_hint_type_name[];
+typedef byte index_clause_map;
+
+/*
+  Bits in index_clause_map : one for each possible FOR clause in
+  USE/FORCE/IGNORE INDEX index hint specification
+*/
+#define INDEX_HINT_MASK_JOIN  (1)
+#define INDEX_HINT_MASK_GROUP (1 << 1)
+#define INDEX_HINT_MASK_ORDER (1 << 2)
+
+#define INDEX_HINT_MASK_ALL (INDEX_HINT_MASK_JOIN | INDEX_HINT_MASK_GROUP | \
+                             INDEX_HINT_MASK_ORDER)
+
+/* Single element of an USE/FORCE/IGNORE INDEX list specified as a SQL hint  */
+class index_hint : public Sql_alloc
+{
+public:
+  /* The type of the hint : USE/FORCE/IGNORE */
+  enum index_hint_type type;
+  /* Where the hit applies to. A bitmask of INDEX_HINT_MASK_<place> values */
+  index_clause_map clause;
+  /* 
+    The index name. Empty (str=NULL) name represents an empty list 
+    USE INDEX () clause 
+  */ 
+  LEX_STRING key_name;
+
+  index_hint (enum index_hint_type type_arg, index_clause_map clause_arg,
+              char *str, uint length) :
+    type(type_arg), clause(clause_arg)
+  {
+    key_name.str= str;
+    key_name.length= length;
+  }
+}; 
+
+/* 
   The state of the lex parsing for selects 
    
    master and slaves are pointers to select_lex.
@@ -394,15 +435,12 @@ public:
   virtual uint get_in_sum_expr();
   virtual TABLE_LIST* get_table_list();
   virtual List<Item>* get_item_list();
-  virtual List<String>* get_use_index();
-  virtual List<String>* get_ignore_index();
   virtual ulong get_table_join_options();
   virtual TABLE_LIST *add_table_to_list(THD *thd, Table_ident *table,
 					LEX_STRING *alias,
 					ulong table_options,
 					thr_lock_type flags= TL_UNLOCK,
-					List<String> *use_index= 0,
-					List<String> *ignore_index= 0,
+					List<index_hint> *hints= 0,
                                         LEX_STRING *option= 0);
   virtual void set_lock_for_tables(thr_lock_type lock_type) {}
 
@@ -532,8 +570,7 @@ public:
   SQL_LIST	      table_list;
   SQL_LIST	      group_list; /* GROUP BY clause. */
   List<Item>          item_list;  /* list of fields & expressions */
-  List<String>        interval_list, use_index, *use_index_ptr,
-		      ignore_index, *ignore_index_ptr;
+  List<String>        interval_list;
   bool	              is_item_list_lookup;
   /* 
     Usualy it is pointer to ftfunc_list_alloc, but in union used to create fake
@@ -680,8 +717,7 @@ public:
 				LEX_STRING *alias,
 				ulong table_options,
 				thr_lock_type flags= TL_UNLOCK,
-				List<String> *use_index= 0,
-				List<String> *ignore_index= 0,
+				List<index_hint> *hints= 0,
                                 LEX_STRING *option= 0);
   TABLE_LIST* get_table_list();
   bool init_nested_join(THD *thd);
@@ -690,8 +726,6 @@ public:
   void add_joined_table(TABLE_LIST *table);
   TABLE_LIST *convert_right_join();
   List<Item>* get_item_list();
-  List<String>* get_use_index();
-  List<String>* get_ignore_index();
   ulong get_table_join_options();
   void set_lock_for_tables(thr_lock_type lock_type);
   inline void init_order()
@@ -731,6 +765,33 @@ public:
     select lexes.
   */
   void cleanup_all_joins(bool full);
+
+  void set_index_hint_type(enum index_hint_type type, index_clause_map clause);
+
+  /* 
+   Add a index hint to the tagged list of hints. The type and clause of the
+   hint will be the current ones (set by set_index_hint()) 
+  */
+  bool add_index_hint (THD *thd, char *str, uint length);
+
+  /* make a list to hold index hints */
+  void alloc_index_hints (THD *thd);
+  /* read and clear the index hints */
+  List<index_hint>* pop_index_hints(void) 
+  {
+    List<index_hint> *hints= index_hints;
+    index_hints= NULL;
+    return hints;
+  }
+
+  void clear_index_hints(void) { index_hints= NULL; }
+
+private:  
+  /* current index hint kind. used in filling up index_hints */
+  enum index_hint_type current_index_hint_type;
+  index_clause_map current_index_hint_clause;
+  /* a list of USE/FORCE/IGNORE INDEX */
+  List<index_hint> *index_hints;
 };
 typedef class st_select_lex SELECT_LEX;
 
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index bfcbd4663b4..36f2aadb6c1 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -1414,8 +1414,7 @@ int prepare_schema_table(THD *thd, LEX *lex, Table_ident *table_ident,
       /* 'parent_lex' is used in init_query() so it must be before it. */
       sel->parent_lex= lex;
       sel->init_query();
-      if (!sel->add_table_to_list(thd, table_ident, 0, 0, TL_READ, 
-                                 (List<String> *) 0, (List<String> *) 0))
+      if (!sel->add_table_to_list(thd, table_ident, 0, 0, TL_READ))
         DBUG_RETURN(1);
       lex->query_tables_last= query_tables_last;
       TABLE_LIST *table_list= (TABLE_LIST*) sel->table_list.first;
@@ -5458,8 +5457,7 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
 					     LEX_STRING *alias,
 					     ulong table_options,
 					     thr_lock_type lock_type,
-					     List<String> *use_index_arg,
-					     List<String> *ignore_index_arg,
+					     List<index_hint> *index_hints_arg,
                                              LEX_STRING *option)
 {
   register TABLE_LIST *ptr;
@@ -5534,12 +5532,7 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
   }
   ptr->select_lex=  lex->current_select;
   ptr->cacheable_table= 1;
-  if (use_index_arg)
-    ptr->use_index=(List<String> *) thd->memdup((gptr) use_index_arg,
-						sizeof(*use_index_arg));
-  if (ignore_index_arg)
-    ptr->ignore_index=(List<String> *) thd->memdup((gptr) ignore_index_arg,
-						   sizeof(*ignore_index_arg));
+  ptr->index_hints= index_hints_arg;
   ptr->option= option ? option->str : 0;
   /* check that used name is unique */
   if (lock_type != TL_IGNORE)
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index c901655f2d3..d78b722632d 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -163,13 +163,15 @@ static COND *make_cond_for_table(COND *cond,table_map table,
 static Item* part_of_refkey(TABLE *form,Field *field);
 uint find_shortest_key(TABLE *table, const key_map *usable_keys);
 static bool test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,
-				    ha_rows select_limit, bool no_changes);
+				    ha_rows select_limit, bool no_changes,
+                                    key_map *map);
 static bool list_contains_unique_index(TABLE *table,
                           bool (*find_func) (Field *, void *), void *data);
 static bool find_field_in_item_list (Field *field, void *data);
 static bool find_field_in_order_list (Field *field, void *data);
 static int create_sort_index(THD *thd, JOIN *join, ORDER *order,
-			     ha_rows filesort_limit, ha_rows select_limit);
+			     ha_rows filesort_limit, ha_rows select_limit,
+                             bool is_order_by);
 static int remove_duplicates(JOIN *join,TABLE *entry,List<Item> &fields,
 			     Item *having);
 static int remove_dup_with_compare(THD *thd, TABLE *entry, Field **field,
@@ -1024,14 +1026,15 @@ JOIN::optimize()
     JOIN_TAB *tab= &join_tab[const_tables];
     bool all_order_fields_used;
     if (order)
-      skip_sort_order= test_if_skip_sort_order(tab, order, select_limit, 1);
+      skip_sort_order= test_if_skip_sort_order(tab, order, select_limit, 1, 
+        &tab->table->keys_in_use_for_order_by);
     if ((group_list=create_distinct_group(thd, select_lex->ref_pointer_array,
                                           order, fields_list,
 				          &all_order_fields_used)))
     {
       bool skip_group= (skip_sort_order &&
-			test_if_skip_sort_order(tab, group_list, select_limit,
-						1) != 0);
+        test_if_skip_sort_order(tab, group_list, select_limit, 1, 
+                                &tab->table->keys_in_use_for_group_by) != 0);
       if ((skip_group && all_order_fields_used) ||
 	  select_limit == HA_POS_ERROR ||
 	  (order && !skip_sort_order))
@@ -1229,7 +1232,9 @@ JOIN::optimize()
         ((group_list &&
           (!simple_group ||
            !test_if_skip_sort_order(&join_tab[const_tables], group_list,
-                                    unit->select_limit_cnt, 0))) ||
+                                    unit->select_limit_cnt, 0, 
+                                    &join_tab[const_tables].table->
+                                    keys_in_use_for_group_by))) ||
          select_distinct) &&
         tmp_table_param.quick_group && !procedure)
     {
@@ -1331,7 +1336,7 @@ JOIN::optimize()
       DBUG_PRINT("info",("Sorting for group"));
       thd->proc_info="Sorting for group";
       if (create_sort_index(thd, this, group_list,
-			    HA_POS_ERROR, HA_POS_ERROR) ||
+			    HA_POS_ERROR, HA_POS_ERROR, FALSE) ||
 	  alloc_group_fields(this, group_list) ||
           make_sum_func_list(all_fields, fields_list, 1) ||
           setup_sum_funcs(thd, sum_funcs))
@@ -1348,7 +1353,7 @@ JOIN::optimize()
 	DBUG_PRINT("info",("Sorting for order"));
 	thd->proc_info="Sorting for order";
 	if (create_sort_index(thd, this, order,
-                              HA_POS_ERROR, HA_POS_ERROR))
+                              HA_POS_ERROR, HA_POS_ERROR, TRUE))
 	  DBUG_RETURN(1);
 	order=0;
       }
@@ -1375,7 +1380,9 @@ JOIN::optimize()
       {
  	/* Should always succeed */
 	if (test_if_skip_sort_order(&join_tab[const_tables],
-				    order, unit->select_limit_cnt, 0))
+				    order, unit->select_limit_cnt, 0, 
+                                    &join_tab[const_tables].table->
+                                      keys_in_use_for_order_by))
 	  order=0;
       }
     }
@@ -1568,7 +1575,9 @@ JOIN::exec()
 	(const_tables == tables ||
  	 ((simple_order || skip_sort_order) &&
 	  test_if_skip_sort_order(&join_tab[const_tables], order,
-				  select_limit, 0))))
+				  select_limit, 0, 
+                                  &join_tab[const_tables].table->
+                                    keys_in_use_for_order_by))))
       order=0;
     having= tmp_having;
     select_describe(this, need_tmp,
@@ -1744,7 +1753,7 @@ JOIN::exec()
 	  DBUG_VOID_RETURN;
 	}
 	if (create_sort_index(thd, curr_join, curr_join->group_list,
-			      HA_POS_ERROR, HA_POS_ERROR) ||
+			      HA_POS_ERROR, HA_POS_ERROR, FALSE) ||
 	    make_group_fields(this, curr_join))
 	{
 	  DBUG_VOID_RETURN;
@@ -1960,7 +1969,8 @@ JOIN::exec()
 			    curr_join->group_list : curr_join->order,
 			    curr_join->select_limit,
 			    (select_options & OPTION_FOUND_ROWS ?
-			     HA_POS_ERROR : unit->select_limit_cnt)))
+			     HA_POS_ERROR : unit->select_limit_cnt),
+                            curr_join->group_list ? TRUE : FALSE))
 	DBUG_VOID_RETURN;
       sortorder= curr_join->sortorder;
       if (curr_join->const_tables != curr_join->tables &&
@@ -3964,7 +3974,7 @@ best_access_path(JOIN      *join,
             /* Limit the number of matched rows */
             tmp= records;
             set_if_smaller(tmp, (double) thd->variables.max_seeks_for_key);
-            if (table->used_keys.is_set(key))
+            if (table->covering_keys.is_set(key))
             {
               /* we can use only index tree */
               uint keys_per_block= table->file->stats.block_size/2/
@@ -4131,7 +4141,7 @@ best_access_path(JOIN      *join,
 
             /* Limit the number of matched rows */
             set_if_smaller(tmp, (double) thd->variables.max_seeks_for_key);
-            if (table->used_keys.is_set(key))
+            if (table->covering_keys.is_set(key))
             {
               /* we can use only index tree */
               uint keys_per_block= table->file->stats.block_size/2/
@@ -4190,7 +4200,7 @@ best_access_path(JOIN      *join,
       !(s->quick && best_key && s->quick->index == best_key->key &&      // (2)
         best_max_key_part >= s->table->quick_key_parts[best_key->key]) &&// (2)
       !((s->table->file->ha_table_flags() & HA_TABLE_SCAN_ON_INDEX) &&   // (3)
-        ! s->table->used_keys.is_clear_all() && best_key) &&             // (3)
+        ! s->table->covering_keys.is_clear_all() && best_key) &&         // (3)
       !(s->table->force_index && best_key && !s->quick))                 // (4)
   {                                             // Check full join
     ha_rows rnd_records= s->found_records;
@@ -6098,7 +6108,7 @@ make_join_readinfo(JOIN *join, ulonglong options)
         (table == join->sort_by_table &&
          (!join->order || join->skip_sort_order ||
           test_if_skip_sort_order(tab, join->order, join->select_limit,
-                                  1))
+                                  1, &table->keys_in_use_for_order_by))
         ) ||
         (join->sort_by_table == (TABLE *) 1 && i != join->const_tables))
       ordered_set= 1;
@@ -6115,7 +6125,7 @@ make_join_readinfo(JOIN *join, ulonglong options)
       table->status=STATUS_NO_RECORD;
       tab->read_first_record= join_read_const;
       tab->read_record.read_record= join_no_more_records;
-      if (table->used_keys.is_set(tab->ref.key) &&
+      if (table->covering_keys.is_set(tab->ref.key) &&
           !table->no_keyread)
       {
         table->key_read=1;
@@ -6133,7 +6143,7 @@ make_join_readinfo(JOIN *join, ulonglong options)
       tab->quick=0;
       tab->read_first_record= join_read_key;
       tab->read_record.read_record= join_no_more_records;
-      if (table->used_keys.is_set(tab->ref.key) &&
+      if (table->covering_keys.is_set(tab->ref.key) &&
 	  !table->no_keyread)
       {
 	table->key_read=1;
@@ -6150,7 +6160,7 @@ make_join_readinfo(JOIN *join, ulonglong options)
       }
       delete tab->quick;
       tab->quick=0;
-      if (table->used_keys.is_set(tab->ref.key) &&
+      if (table->covering_keys.is_set(tab->ref.key) &&
 	  !table->no_keyread)
       {
 	table->key_read=1;
@@ -6236,15 +6246,15 @@ make_join_readinfo(JOIN *join, ulonglong options)
 	{
 	  if (tab->select && tab->select->quick &&
               tab->select->quick->index != MAX_KEY && //not index_merge
-	      table->used_keys.is_set(tab->select->quick->index))
+	      table->covering_keys.is_set(tab->select->quick->index))
 	  {
 	    table->key_read=1;
 	    table->file->extra(HA_EXTRA_KEYREAD);
 	  }
-	  else if (!table->used_keys.is_clear_all() &&
+	  else if (!table->covering_keys.is_clear_all() &&
 		   !(tab->select && tab->select->quick))
 	  {					// Only read index tree
-	    tab->index=find_shortest_key(table, & table->used_keys);
+	    tab->index=find_shortest_key(table, & table->covering_keys);
 	    tab->read_first_record= join_read_first;
 	    tab->type=JT_NEXT;		// Read with index_first / index_next
 	  }
@@ -9378,7 +9388,7 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
   table->copy_blobs= 1;
   table->in_use= thd;
   table->quick_keys.init();
-  table->used_keys.init();
+  table->covering_keys.init();
   table->keys_in_use_for_query.init();
 
   table->s= share;
@@ -11003,7 +11013,7 @@ join_read_const_table(JOIN_TAB *tab, POSITION *pos)
   }
   else
   {
-    if (!table->key_read && table->used_keys.is_set(tab->ref.key) &&
+    if (!table->key_read && table->covering_keys.is_set(tab->ref.key) &&
 	!table->no_keyread &&
         (int) table->reginfo.lock_type <= (int) TL_READ_HIGH_PRIORITY)
     {
@@ -11310,7 +11320,7 @@ join_read_first(JOIN_TAB *tab)
 {
   int error;
   TABLE *table=tab->table;
-  if (!table->key_read && table->used_keys.is_set(tab->index) &&
+  if (!table->key_read && table->covering_keys.is_set(tab->index) &&
       !table->no_keyread)
   {
     table->key_read=1;
@@ -11349,7 +11359,7 @@ join_read_last(JOIN_TAB *tab)
 {
   TABLE *table=tab->table;
   int error;
-  if (!table->key_read && table->used_keys.is_set(tab->index) &&
+  if (!table->key_read && table->covering_keys.is_set(tab->index) &&
       !table->no_keyread)
   {
     table->key_read=1;
@@ -12373,7 +12383,7 @@ find_field_in_item_list (Field *field, void *data)
 
 static bool
 test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
-			bool no_changes)
+			bool no_changes, key_map *map)
 {
   int ref_key;
   uint ref_key_parts;
@@ -12390,7 +12400,16 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
     Keys disabled by ALTER TABLE ... DISABLE KEYS should have already
     been taken into account.
   */
-  DBUG_ASSERT(usable_keys.is_subset(table->s->keys_in_use));
+  usable_keys= *map;
+
+  /* 
+    If there is a covering index, and we have IGNORE INDEX FOR GROUP/ORDER
+    and this index is used for the JOIN part, then we have to ignore the
+    IGNORE INDEX FOR GROUP/ORDER
+  */  
+  if (table->key_read ||
+      (table->covering_keys.is_set(tab->index) && !table->no_keyread))
+    usable_keys.set_bit (tab->index);
 
   for (ORDER *tmp_order=order; tmp_order ; tmp_order=tmp_order->next)
   {
@@ -12448,8 +12467,8 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
 	If using index only read, only consider other possible index only
 	keys
       */
-      if (table->used_keys.is_set(ref_key))
-	usable_keys.intersect(table->used_keys);
+      if (table->covering_keys.is_set(ref_key))
+	usable_keys.intersect(table->covering_keys);
       if ((new_ref_key= test_if_subkey(order, table, ref_key, ref_key_parts,
 				       &usable_keys)) < MAX_KEY)
       {
@@ -12564,7 +12583,7 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
     if (select_limit >= table->file->stats.records)
     {
       keys= *table->file->keys_to_use_for_scanning();
-      keys.merge(table->used_keys);
+      keys.merge(table->covering_keys);
 
       /*
 	We are adding here also the index specified in FORCE INDEX clause, 
@@ -12592,7 +12611,7 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
 	    tab->read_first_record=  (flag > 0 ? join_read_first:
 				      join_read_last);
 	    tab->type=JT_NEXT;	// Read with index_first(), index_next()
-	    if (table->used_keys.is_set(nr))
+	    if (table->covering_keys.is_set(nr))
 	    {
 	      table->key_read=1;
 	      table->file->extra(HA_EXTRA_KEYREAD);
@@ -12618,6 +12637,8 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
      filesort_limit	Max number of rows that needs to be sorted
      select_limit	Max number of rows in final output
 		        Used to decide if we should use index or not
+     is_order_by        true if we are sorting on ORDER BY, false if GROUP BY
+                        Used to decide if we should use index or not     
 
 
   IMPLEMENTATION
@@ -12636,7 +12657,8 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
 
 static int
 create_sort_index(THD *thd, JOIN *join, ORDER *order,
-		  ha_rows filesort_limit, ha_rows select_limit)
+		  ha_rows filesort_limit, ha_rows select_limit,
+                  bool is_order_by)
 {
   uint length= 0;
   ha_rows examined_rows;
@@ -12657,7 +12679,9 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
   */
   if ((order != join->group_list || 
        !(join->select_options & SELECT_BIG_RESULT)) &&
-      test_if_skip_sort_order(tab,order,select_limit,0))
+      test_if_skip_sort_order(tab,order,select_limit,0, 
+                              is_order_by ?  &table->keys_in_use_for_order_by :
+                              &table->keys_in_use_for_group_by))
     DBUG_RETURN(0);
   for (ORDER *ord= join->order; ord; ord= ord->next)
     length++;
@@ -15285,7 +15309,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
       /* Build "Extra" field and add it to item_list. */
       my_bool key_read=table->key_read;
       if ((tab->type == JT_NEXT || tab->type == JT_CONST) &&
-          table->used_keys.is_set(tab->index))
+          table->covering_keys.is_set(tab->index))
 	key_read=1;
       if (quick_type == QUICK_SELECT_I::QS_TYPE_ROR_INTERSECT &&
           !((QUICK_ROR_INTERSECT_SELECT*)tab->select->quick)->need_to_fetch_row)
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index a91eb28b191..42cd0dcb42b 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -2266,8 +2266,7 @@ int make_table_list(THD *thd, SELECT_LEX *sel,
   ident_table.length= strlen(table);
   table_ident= new Table_ident(thd, ident_db, ident_table, 1);
   sel->init_query();
-  if (!sel->add_table_to_list(thd, table_ident, 0, 0, TL_READ,
-                             (List<String> *) 0, (List<String> *) 0))
+  if (!sel->add_table_to_list(thd, table_ident, 0, 0, TL_READ))
     return 1;
   return 0;
 }
@@ -5033,8 +5032,7 @@ int make_schema_select(THD *thd, SELECT_LEX *sel,
                   strlen(schema_table->table_name), 0);
   if (schema_table->old_format(thd, schema_table) ||   /* Handle old syntax */
       !sel->add_table_to_list(thd, new Table_ident(thd, db, table, 0),
-                              0, 0, TL_READ, (List<String> *) 0,
-                              (List<String> *) 0))
+                              0, 0, TL_READ))
   {
     DBUG_RETURN(1);
   }
diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index 5aea05a9d39..0b4632edfbe 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -126,7 +126,7 @@ int mysql_update(THD *thd,
 #endif
   uint          table_count= 0;
   ha_rows	updated, found;
-  key_map	old_used_keys;
+  key_map	old_covering_keys;
   TABLE		*table;
   SQL_SELECT	*select;
   READ_RECORD	info;
@@ -165,8 +165,8 @@ int mysql_update(THD *thd,
   thd->proc_info="init";
   table= table_list->table;
 
-  /* Calculate "table->used_keys" based on the WHERE */
-  table->used_keys= table->s->keys_in_use;
+  /* Calculate "table->covering_keys" based on the WHERE */
+  table->covering_keys= table->s->keys_in_use;
   table->quick_keys.clear_all();
 
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
@@ -176,7 +176,7 @@ int mysql_update(THD *thd,
   if (mysql_prepare_update(thd, table_list, &conds, order_num, order))
     DBUG_RETURN(1);
 
-  old_used_keys= table->used_keys;		// Keys used in WHERE
+  old_covering_keys= table->covering_keys;		// Keys used in WHERE
   /* Check the fields we are going to modify */
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
   table_list->grant.want_privilege= table->grant.want_privilege= want_privilege;
@@ -229,7 +229,7 @@ int mysql_update(THD *thd,
       limit= 0;                                   // Impossible WHERE
   }
   // Don't count on usage of 'only index' when calculating which key to use
-  table->used_keys.clear_all();
+  table->covering_keys.clear_all();
 
 #ifdef WITH_PARTITION_STORAGE_ENGINE
   if (prune_partitions(thd, table, conds))
@@ -304,7 +304,7 @@ int mysql_update(THD *thd,
       We can't update table directly;  We must first search after all
       matching rows before updating the table!
     */
-    if (used_index < MAX_KEY && old_used_keys.is_set(used_index))
+    if (used_index < MAX_KEY && old_covering_keys.is_set(used_index))
     {
       table->key_read=1;
       table->mark_columns_used_by_index(used_index);
@@ -1092,7 +1092,7 @@ int multi_update::prepare(List<Item> &not_used_values,
   }
 
   /*
-    We have to check values after setup_tables to get used_keys right in
+    We have to check values after setup_tables to get covering_keys right in
     reference tables
   */
 
@@ -1119,7 +1119,7 @@ int multi_update::prepare(List<Item> &not_used_values,
       update.link_in_list((byte*) tl, (byte**) &tl->next_local);
       tl->shared= table_count++;
       table->no_keyread=1;
-      table->used_keys.clear_all();
+      table->covering_keys.clear_all();
       table->pos_in_table_list= tl;
     }
   }
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 5d24fb4fa65..01a813b4357 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -481,6 +481,7 @@ Item* handle_sql2003_note184_exception(THD *thd, Item* left, bool equal,
   struct st_lex *lex;
   sp_head *sphead;
   struct p_elem_val *p_elem_value;
+  enum index_hint_type index_hint;
 }
 
 %{
@@ -1162,7 +1163,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 	btree_or_rtree
 
 %type <string_list>
-	key_usage_list using_list
+	using_list
 
 %type <key_part>
 	key_part
@@ -1233,7 +1234,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 	opt_column_list grant_privileges grant_ident grant_list grant_option
 	object_privilege object_privilege_list user_list rename_list
 	clear_privileges flush_options flush_option
-	equal optional_braces opt_key_definition key_usage_list2
+	equal optional_braces
 	opt_mi_check_type opt_to mi_check_types normal_join
 	db_to_db table_to_table_list table_to_table opt_table_list opt_as
 	handler_rkey_function handler_read_or_scan
@@ -1269,6 +1270,8 @@ END_OF_INPUT
 %type <spblock> sp_decls sp_decl
 %type <lex> sp_cursor_stmt
 %type <spname> sp_name
+%type <index_hint> index_hint_type
+%type <num> index_hint_clause
 
 %type <NONE>
 	'-' '+' '*' '/' '%' '(' ')'
@@ -5940,12 +5943,8 @@ keycache_list:
 assign_to_keycache:
         table_ident cache_keys_spec
         {
-          LEX *lex=Lex;
-          SELECT_LEX *sel= &lex->select_lex;
-          if (!sel->add_table_to_list(lex->thd, $1, NULL, 0,
-                                      TL_READ,
-                                      sel->get_use_index(),
-                                      (List<String> *)0))
+          if (!Select->add_table_to_list(YYTHD, $1, NULL, 0, TL_READ, 
+                                      Select->pop_index_hints()))
             MYSQL_YYABORT;
         }
         ;
@@ -5972,33 +5971,26 @@ preload_list:
 preload_keys:
 	table_ident cache_keys_spec opt_ignore_leaves
 	{
-	  LEX *lex=Lex;
-	  SELECT_LEX *sel= &lex->select_lex;
-	  if (!sel->add_table_to_list(lex->thd, $1, NULL, $3,
-                                      TL_READ,
-                                      sel->get_use_index(),
-                                      (List<String> *)0))
+	  if (!Select->add_table_to_list(YYTHD, $1, NULL, $3, TL_READ,
+                                      Select->pop_index_hints()))
             MYSQL_YYABORT;
 	}
 	;
 
 cache_keys_spec:
-        { Select->interval_list.empty(); }
-        cache_key_list_or_empty
-        {
-          LEX *lex=Lex;
-          SELECT_LEX *sel= &lex->select_lex;
-          sel->use_index= sel->interval_list;
+        { 
+          Lex->select_lex.alloc_index_hints(YYTHD);
+          Select->set_index_hint_type(INDEX_HINT_USE, 
+                                      global_system_variables.old_mode ? 
+                                        INDEX_HINT_MASK_JOIN : 
+                                        INDEX_HINT_MASK_ALL);
         }
+        cache_key_list_or_empty
         ;
 
 cache_key_list_or_empty:
-	/* empty */	{ Lex->select_lex.use_index_ptr= 0; }
-	| opt_key_or_index '(' key_usage_list2 ')'
-	  {
-            SELECT_LEX *sel= &Lex->select_lex;
-	    sel->use_index_ptr= &sel->use_index;
-	  }
+	/* empty */	{ }
+	| key_or_index '(' opt_key_usage_list ')'
 	;
 
 opt_ignore_leaves:
@@ -7371,20 +7363,16 @@ normal_join:
 table_factor:
 	{
 	  SELECT_LEX *sel= Select;
-	  sel->use_index_ptr=sel->ignore_index_ptr=0;
 	  sel->table_join_options= 0;
 	}
         table_ident opt_table_alias opt_key_definition
 	{
-	  LEX *lex= Lex;
-	  SELECT_LEX *sel= lex->current_select;
-	  if (!($$= sel->add_table_to_list(lex->thd, $2, $3,
-					   sel->get_table_join_options(),
-					   lex->lock_option,
-					   sel->get_use_index(),
-					   sel->get_ignore_index())))
+	  if (!($$= Select->add_table_to_list(YYTHD, $2, $3,
+					   Select->get_table_join_options(),
+					   Lex->lock_option,
+					   Select->pop_index_hints())))
 	    MYSQL_YYABORT;
-          sel->add_joined_table($$);
+          Select->add_joined_table($$);
 	}
 	| '{' ident table_ref LEFT OUTER JOIN_SYM table_ref
           ON
@@ -7453,8 +7441,7 @@ table_factor:
 	    lex->current_select= sel= unit->outer_select();
 	    if (!($$= sel->
                   add_table_to_list(lex->thd, new Table_ident(unit), $6, 0,
-				    TL_READ,(List<String> *)0,
-	                            (List<String> *)0)))
+				    TL_READ)))
 
 	      MYSQL_YYABORT;
             sel->add_joined_table($$);
@@ -7553,52 +7540,67 @@ opt_outer:
 	/* empty */	{}
 	| OUTER		{};
 
+index_hint_clause:
+       /* empty */             
+         { 
+            $$= global_system_variables.old_mode ? 
+                  INDEX_HINT_MASK_JOIN : INDEX_HINT_MASK_ALL; 
+         } 
+       | FOR_SYM JOIN_SYM      { $$= INDEX_HINT_MASK_JOIN;  }
+       | FOR_SYM ORDER_SYM BY  { $$= INDEX_HINT_MASK_ORDER; }
+       | FOR_SYM GROUP BY      { $$= INDEX_HINT_MASK_GROUP; }
+       ;
+
+index_hint_type:
+       FORCE_SYM  { $$= INDEX_HINT_FORCE; }
+       | IGNORE_SYM { $$= INDEX_HINT_IGNORE; } 
+       ;
+
+index_hint_definition:
+       index_hint_type key_or_index index_hint_clause
+       {
+         Select->set_index_hint_type($1, $3);
+       }
+       '(' key_usage_list ')';
+       | USE_SYM key_or_index index_hint_clause
+       {
+         Select->set_index_hint_type(INDEX_HINT_USE, $3);
+       }
+       '(' opt_key_usage_list ')';
+
+
+index_hints_list:
+       index_hint_definition         
+       | index_hints_list index_hint_definition
+       ;
+
+opt_index_hints_list:
+       /* empty */
+       | { Select->alloc_index_hints(YYTHD); } index_hints_list
+       ;
+
 opt_key_definition:
-	/* empty */	{}
-	| USE_SYM    key_usage_list
-          {
-	    SELECT_LEX *sel= Select;
-	    sel->use_index= *$2;
-	    sel->use_index_ptr= &sel->use_index;
-	  }
-	| FORCE_SYM key_usage_list
-          {
-	    SELECT_LEX *sel= Select;
-	    sel->use_index= *$2;
-	    sel->use_index_ptr= &sel->use_index;
-	    sel->table_join_options|= TL_OPTION_FORCE_INDEX;
-	  }
-	| IGNORE_SYM key_usage_list
-	  {
-	    SELECT_LEX *sel= Select;
-	    sel->ignore_index= *$2;
-	    sel->ignore_index_ptr= &sel->ignore_index;
-	  };
+       {  Select->clear_index_hints(); }
+       opt_index_hints_list
+       ;
 
-key_usage_list:
-	key_or_index { Select->interval_list.empty(); }
-        '(' key_list_or_empty ')'
-        { $$= &Select->interval_list; }
+opt_key_usage_list:
+	/* empty */ 		{ Select->add_index_hint(YYTHD, NULL, 0); }
+	| key_usage_list	{}
 	;
 
-key_list_or_empty:
-	/* empty */ 		{}
-	| key_usage_list2	{}
-	;
+key_usage_element:
+	ident           { Select->add_index_hint(YYTHD, $1.str, $1.length); }
+	| PRIMARY_SYM   
+          { 
+            Select->add_index_hint(YYTHD, (char *)"PRIMARY", 7); 
+          }
+        ;
 
-key_usage_list2:
-	key_usage_list2 ',' ident
-        { Select->
-	    interval_list.push_back(new (YYTHD->mem_root) String((const char*) $3.str, $3.length,
-				    system_charset_info)); }
-	| ident
-        { Select->
-	    interval_list.push_back(new (YYTHD->mem_root) String((const char*) $1.str, $1.length,
-				    system_charset_info)); }
-	| PRIMARY_SYM
-        { Select->
-	    interval_list.push_back(new (YYTHD->mem_root) String("PRIMARY", 7,
-				    system_charset_info)); };
+key_usage_list:
+        key_usage_element
+	| key_usage_list ',' key_usage_element
+        ;
 
 using_list:
 	ident
diff --git a/sql/table.cc b/sql/table.cc
index 560f53bae26..daec7492500 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -1338,7 +1338,7 @@ int open_table_from_share(THD *thd, TABLE_SHARE *share, const char *alias,
   if (!(outparam->alias= my_strdup(alias, MYF(MY_WME))))
     goto err;
   outparam->quick_keys.init();
-  outparam->used_keys.init();
+  outparam->covering_keys.init();
   outparam->keys_in_use_for_query.init();
 
   /* Allocate handler */
@@ -4120,6 +4120,175 @@ Item_subselect *st_table_list::containing_subselect()
   return (select_lex ? select_lex->master_unit()->item : 0);
 }
 
+/*
+  Compiles the tagged hints list and fills up the bitmasks.
+
+  SYNOPSIS
+    process_index_hints()
+      table         the TABLE to operate on.
+
+  DESCRIPTION
+    The parser collects the index hints for each table in a "tagged list" 
+    (st_table_list::index_hints). Using the information in this tagged list
+    this function sets the members st_table::keys_in_use_for_query, 
+    st_table::keys_in_use_for_group_by, st_table::keys_in_use_for_order_by,
+    st_table::force_index and st_table::covering_keys.
+
+    Current implementation of the runtime does not allow mixing FORCE INDEX
+    and USE INDEX, so this is checked here. Then the FORCE INDEX list 
+    (if non-empty) is appended to the USE INDEX list and a flag is set.
+
+    Multiple hints of the same kind are processed so that each clause 
+    is applied to what is computed in the previous clause.
+    For example:
+        USE INDEX (i1) USE INDEX (i2)
+    is equivalent to
+        USE INDEX (i1,i2)
+    and means "consider only i1 and i2".
+        
+    Similarly
+        USE INDEX () USE INDEX (i1)
+    is equivalent to
+        USE INDEX (i1)
+    and means "consider only the index i1"
+
+    It is OK to have the same index several times, e.g. "USE INDEX (i1,i1)" is
+    not an error.
+        
+    Different kind of hints (USE/FORCE/IGNORE) are processed in the following
+    order:
+      1. All indexes in USE (or FORCE) INDEX are added to the mask.
+      2. All IGNORE INDEX
+
+    e.g. "USE INDEX i1, IGNORE INDEX i1, USE INDEX i1" will not use i1 at all
+    as if we had "USE INDEX i1, USE INDEX i1, IGNORE INDEX i1".
+
+    As an optimization if there is a covering index, and we have 
+    IGNORE INDEX FOR GROUP/ORDER, and this index is used for the JOIN part, 
+    then we have to ignore the IGNORE INDEX FROM GROUP/ORDER.
+
+  RETURN VALUE
+    FALSE                no errors found
+    TRUE                 found and reported an error.
+*/
+bool st_table_list::process_index_hints(TABLE *table)
+{
+  /* initialize the result variables */
+  table->keys_in_use_for_query= table->keys_in_use_for_group_by= 
+    table->keys_in_use_for_order_by= table->s->keys_in_use;
+
+  /* index hint list processing */
+  if (index_hints)
+  {
+    key_map index_join[INDEX_HINT_FORCE + 1];
+    key_map index_order[INDEX_HINT_FORCE + 1];
+    key_map index_group[INDEX_HINT_FORCE + 1];
+    index_hint *hint;
+    int type;
+    bool have_empty_use_join= FALSE, have_empty_use_order= FALSE, 
+         have_empty_use_group= FALSE;
+    List_iterator <index_hint> iter(*index_hints);
+
+    /* initialize temporary variables used to collect hints of each kind */
+    for (type= INDEX_HINT_IGNORE; type <= INDEX_HINT_FORCE; type++)
+    {
+      index_join[type].clear_all();
+      index_order[type].clear_all();
+      index_group[type].clear_all();
+    }
+
+    /* iterate over the hints list */
+    while ((hint= iter++))
+    {
+      uint pos;
+
+      /* process empty USE INDEX () */
+      if (hint->type == INDEX_HINT_USE && !hint->key_name.str)
+      {
+        if (hint->clause & INDEX_HINT_MASK_JOIN)
+        {
+          index_join[hint->type].clear_all();
+          have_empty_use_join= TRUE;
+        }
+        if (hint->clause & INDEX_HINT_MASK_ORDER)
+        {
+          index_order[hint->type].clear_all();
+          have_empty_use_order= TRUE;
+        }
+        if (hint->clause & INDEX_HINT_MASK_GROUP)
+        {
+          index_group[hint->type].clear_all();
+          have_empty_use_group= TRUE;
+        }
+        continue;
+      }
+
+      /* 
+        Check if an index with the given name exists and get his offset in 
+        the keys bitmask for the table 
+      */
+      if (table->s->keynames.type_names == 0 ||
+          (pos= find_type(&table->s->keynames, hint->key_name.str,
+                          hint->key_name.length, 1)) <= 0)
+      {
+        my_error(ER_KEY_DOES_NOT_EXITS, MYF(0), hint->key_name.str, alias);
+        return 1;
+      }
+
+      pos--;
+
+      /* add to the appropriate clause mask */
+      if (hint->clause & INDEX_HINT_MASK_JOIN)
+        index_join[hint->type].set_bit (pos);
+      if (hint->clause & INDEX_HINT_MASK_ORDER)
+        index_order[hint->type].set_bit (pos);
+      if (hint->clause & INDEX_HINT_MASK_GROUP)
+        index_group[hint->type].set_bit (pos);
+    }
+
+    /* cannot mix USE INDEX and FORCE INDEX */
+    if ((!index_join[INDEX_HINT_FORCE].is_clear_all() ||
+         !index_order[INDEX_HINT_FORCE].is_clear_all() ||
+         !index_group[INDEX_HINT_FORCE].is_clear_all()) &&
+        (!index_join[INDEX_HINT_USE].is_clear_all() ||  have_empty_use_join ||
+         !index_order[INDEX_HINT_USE].is_clear_all() || have_empty_use_order ||
+         !index_group[INDEX_HINT_USE].is_clear_all() || have_empty_use_group))
+    {
+      my_error(ER_WRONG_USAGE, MYF(0), index_hint_type_name[INDEX_HINT_USE],
+               index_hint_type_name[INDEX_HINT_FORCE]);
+      return 1;
+    }
+
+    /* process FORCE INDEX as USE INDEX with a flag */
+    if (!index_join[INDEX_HINT_FORCE].is_clear_all() ||
+        !index_order[INDEX_HINT_FORCE].is_clear_all() ||
+        !index_group[INDEX_HINT_FORCE].is_clear_all())
+    {
+      table->force_index= TRUE;
+      index_join[INDEX_HINT_USE].merge(index_join[INDEX_HINT_FORCE]);
+      index_order[INDEX_HINT_USE].merge(index_order[INDEX_HINT_FORCE]);
+      index_group[INDEX_HINT_USE].merge(index_group[INDEX_HINT_FORCE]);
+    }
+
+    /* apply USE INDEX */
+    if (!index_join[INDEX_HINT_USE].is_clear_all() || have_empty_use_join)
+      table->keys_in_use_for_query= index_join[INDEX_HINT_USE];
+    if (!index_order[INDEX_HINT_USE].is_clear_all() || have_empty_use_order)
+      table->keys_in_use_for_order_by= index_order[INDEX_HINT_USE];
+    if (!index_group[INDEX_HINT_USE].is_clear_all() || have_empty_use_group)
+      table->keys_in_use_for_group_by= index_group[INDEX_HINT_USE];
+
+    /* apply IGNORE INDEX */
+    table->keys_in_use_for_query.subtract (index_join[INDEX_HINT_IGNORE]);
+    table->keys_in_use_for_order_by.subtract (index_order[INDEX_HINT_IGNORE]);
+    table->keys_in_use_for_group_by.subtract (index_group[INDEX_HINT_IGNORE]);
+  }
+
+  /* make sure covering_keys don't include indexes disabled with a hint */
+  table->covering_keys.intersect(table->keys_in_use_for_query);
+  return 0;
+}
+
 /*****************************************************************************
 ** Instansiate templates
 *****************************************************************************/
diff --git a/sql/table.h b/sql/table.h
index 54c820d391c..086df5f28f8 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -299,6 +299,12 @@ typedef struct st_table_share
 
 
 /* Information for one open table */
+enum index_hint_type
+{
+  INDEX_HINT_IGNORE,
+  INDEX_HINT_USE,
+  INDEX_HINT_FORCE
+};
 
 struct st_table {
   st_table() {}                               /* Remove gcc warning */
@@ -318,8 +324,12 @@ struct st_table {
   byte *write_row_record;		/* Used as optimisation in
 					   THD::write_row */
   byte *insert_values;                  /* used by INSERT ... UPDATE */
-  key_map quick_keys, used_keys;
-
+  /* 
+    Map of keys that can be used to retrieve all data from this table 
+    needed by the query without reading the row.
+  */
+  key_map covering_keys;
+  key_map quick_keys, merge_keys;
   /*
     A set of keys that can be used in the query that references this
     table.
@@ -332,7 +342,10 @@ struct st_table {
     The set is implemented as a bitmap.
   */
   key_map keys_in_use_for_query;
-  key_map merge_keys;
+  /* Map of keys that can be used to calculate GROUP BY without sorting */
+  key_map keys_in_use_for_group_by;
+  /* Map of keys that can be used to calculate ORDER BY without sorting */
+  key_map keys_in_use_for_order_by;
   KEY  *key_info;			/* data of keys in database */
 
   Field *next_number_field;		/* Set if next_number is activated */
@@ -666,6 +679,7 @@ public:
          (TABLE_LIST::join_using_fields != NULL)
 */
 
+class index_hint;
 typedef struct st_table_list
 {
   st_table_list() {}                          /* Remove gcc warning */
@@ -722,7 +736,7 @@ typedef struct st_table_list
   */
   struct st_table_list *next_name_resolution_table;
   /* Index names in a "... JOIN ... USE/IGNORE INDEX ..." clause. */
-  List<String> *use_index, *ignore_index;
+  List<index_hint> *index_hints;
   TABLE        *table;                          /* opened table */
   uint          table_id; /* table id (from binlog) for opened table */
   /*
@@ -896,6 +910,13 @@ typedef struct st_table_list
   void reinit_before_use(THD *thd);
   Item_subselect *containing_subselect();
 
+  /* 
+    Compiles the tagged hints list and fills up st_table::keys_in_use_for_query,
+    st_table::keys_in_use_for_group_by, st_table::keys_in_use_for_order_by,
+    st_table::force_index and st_table::covering_keys.
+  */
+  bool process_index_hints(TABLE *table);
+
 private:
   bool prep_check_option(THD *thd, uint8 check_opt_type);
   bool prep_where(THD *thd, Item **conds, bool no_where_clause);
diff --git a/storage/myisam/ha_myisam.cc b/storage/myisam/ha_myisam.cc
index 06ec5c4b44e..4d358008058 100644
--- a/storage/myisam/ha_myisam.cc
+++ b/storage/myisam/ha_myisam.cc
@@ -1121,23 +1121,22 @@ int ha_myisam::assign_to_keycache(THD* thd, HA_CHECK_OPT *check_opt)
   KEY_CACHE *new_key_cache= check_opt->key_cache;
   const char *errmsg= 0;
   int error= HA_ADMIN_OK;
-  ulonglong map= ~(ulonglong) 0;
+  ulonglong map;
   TABLE_LIST *table_list= table->pos_in_table_list;
   DBUG_ENTER("ha_myisam::assign_to_keycache");
 
-  /* Check validity of the index references */
-  if (table_list->use_index)
+  table->keys_in_use_for_query.clear_all();
+
+  if (table_list->process_index_hints(table))
   {
-    /* We only come here when the user did specify an index map */
-    key_map kmap;
-    if (get_key_map_from_key_list(&kmap, table, table_list->use_index))
-    {
-      errmsg= thd->net.last_error;
-      error= HA_ADMIN_FAILED;
-      goto err;
-    }
-    map= kmap.to_ulonglong();
+    errmsg= thd->net.last_error;
+    error= HA_ADMIN_FAILED;
+    goto err;
   }
+  map= ~(ulonglong) 0;
+  if (!table->keys_in_use_for_query.is_clear_all())
+    /* use all keys if there's no list specified by the user through hints */
+    map= table->keys_in_use_for_query.to_ulonglong();
 
   if ((error= mi_assign_to_key_cache(file, map, new_key_cache)))
   { 
@@ -1173,27 +1172,27 @@ int ha_myisam::preload_keys(THD* thd, HA_CHECK_OPT *check_opt)
 {
   int error;
   const char *errmsg;
-  ulonglong map= ~(ulonglong) 0;
+  ulonglong map;
   TABLE_LIST *table_list= table->pos_in_table_list;
   my_bool ignore_leaves= table_list->ignore_leaves;
 
   DBUG_ENTER("ha_myisam::preload_keys");
 
-  /* Check validity of the index references */
-  if (table_list->use_index)
+  table->keys_in_use_for_query.clear_all();
+
+  if (table_list->process_index_hints(table))
   {
-    key_map kmap;
-    get_key_map_from_key_list(&kmap, table, table_list->use_index);
-    if (kmap.is_set_all())
-    {
-      errmsg= thd->net.last_error;
-      error= HA_ADMIN_FAILED;
-      goto err;
-    }
-    if (!kmap.is_clear_all())
-      map= kmap.to_ulonglong();
+    errmsg= thd->net.last_error;
+    error= HA_ADMIN_FAILED;
+    goto err;
   }
 
+  map= ~(ulonglong) 0;
+  /* Check validity of the index references */
+  if (!table->keys_in_use_for_query.is_clear_all())
+    /* use all keys if there's no list specified by the user through hints */
+    map= table->keys_in_use_for_query.to_ulonglong();
+
   mi_extra(file, HA_EXTRA_PRELOAD_BUFFER_SIZE,
            (void *) &thd->variables.preload_buff_size);