MDEV-10360: Extended keys: index properties depend on index order

TABLE_SHARE::init_from_binary_frm_image has a rule: if an index
has a partially-covered column (like in "KEY(col(N))" ), then dont
provide "Extended Keys" feature for this index.

The problem was that due to coding error Extended Keys feature was
disabled for *ALL* subsequent indexes. Fixed the error.

mysql-test/r/innodb_ext_key.result

@@ -1064,5 +1064,50 @@ explain select * from t1 where col1='1234567890-a';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	idx1	NULL	NULL	NULL	#	Using where
 drop table t0,t1;
+# 
+# MDEV-10360: Extended keys: index properties depend on index order
+# 
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1 (
+index_id bigint(20) unsigned NOT NULL,
+index_class varchar(265) COLLATE latin1_general_ci DEFAULT NULL ,
+index_object_id int(10) unsigned NOT NULL DEFAULT '0' ,
+index_date_updated int(10) unsigned DEFAULT NULL ,
+PRIMARY KEY (index_id),
+KEY object (index_class(181),index_object_id),
+KEY index_date_updated (index_date_updated)
+) engine=innodb;
+create table t2 (
+index_id bigint(20) unsigned NOT NULL,
+index_class varchar(265) COLLATE latin1_general_ci DEFAULT NULL ,
+index_object_id int(10) unsigned NOT NULL DEFAULT '0' ,
+index_date_updated int(10) unsigned DEFAULT NULL ,
+PRIMARY KEY (index_id),
+KEY index_date_updated (index_date_updated),
+KEY object (index_class(181),index_object_id)
+) engine=innodb;
+insert into t1 select 
+@a:=A.a + 10*B.a + 100*C.a,
+concat('val-', @a),
+123456,
+A.a + 10*B.a
+from 
+t0 A, t0 B, t0 C;
+insert into t2 select * from t1;
+# This must have the same query plan as the query below it:
+# type=range, key=index_date_updated, key_len=13
+explain 
+select * from t1 force index(index_date_updated) 
+where index_date_updated= 10 and index_id < 800;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	index_date_updated	index_date_updated	13	NULL	#	Using index condition
+# This used to work from the start:
+explain 
+select * from t2 force index(index_date_updated) 
+where index_date_updated= 10 and index_id < 800;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	range	index_date_updated	index_date_updated	13	NULL	#	Using index condition
+drop table t0,t1,t2;
 set optimizer_switch=@save_ext_key_optimizer_switch;
 SET SESSION STORAGE_ENGINE=DEFAULT;

mysql-test/t/innodb_ext_key.test

@@ -721,5 +721,58 @@ explain select * from t1 where col1='1234567890-a';
 
 drop table t0,t1;
 
+--echo # 
+--echo # MDEV-10360: Extended keys: index properties depend on index order
+--echo # 
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+
+create table t1 (
+  index_id bigint(20) unsigned NOT NULL,
+  index_class varchar(265) COLLATE latin1_general_ci DEFAULT NULL ,
+  index_object_id int(10) unsigned NOT NULL DEFAULT '0' ,
+  index_date_updated int(10) unsigned DEFAULT NULL ,
+ 
+  PRIMARY KEY (index_id),
+  KEY object (index_class(181),index_object_id),
+  KEY index_date_updated (index_date_updated)
+) engine=innodb;
+
+create table t2 (
+  index_id bigint(20) unsigned NOT NULL,
+  index_class varchar(265) COLLATE latin1_general_ci DEFAULT NULL ,
+  index_object_id int(10) unsigned NOT NULL DEFAULT '0' ,
+  index_date_updated int(10) unsigned DEFAULT NULL ,
+ 
+  PRIMARY KEY (index_id),
+  KEY index_date_updated (index_date_updated),
+  KEY object (index_class(181),index_object_id)
+) engine=innodb;
+
+insert into t1 select 
+  @a:=A.a + 10*B.a + 100*C.a,
+  concat('val-', @a),
+  123456,
+  A.a + 10*B.a
+from 
+  t0 A, t0 B, t0 C;
+
+insert into t2 select * from t1;
+
+--echo # This must have the same query plan as the query below it:
+--echo # type=range, key=index_date_updated, key_len=13
+--replace_column 9 #
+explain 
+select * from t1 force index(index_date_updated) 
+where index_date_updated= 10 and index_id < 800;
+
+--echo # This used to work from the start:
+--replace_column 9 #
+explain 
+select * from t2 force index(index_date_updated) 
+where index_date_updated= 10 and index_id < 800;
+
+drop table t0,t1,t2;
+
 set optimizer_switch=@save_ext_key_optimizer_switch;
 SET SESSION STORAGE_ENGINE=DEFAULT;

sql/table.cc

@@ -1804,6 +1804,7 @@ int TABLE_SHARE::init_from_binary_frm_image(THD *thd, bool write,
       {
         KEY_PART_INFO *new_key_part= (keyinfo-1)->key_part +
                                      (keyinfo-1)->ext_key_parts;
+        uint add_keyparts_for_this_key= add_first_key_parts;
 
         /* 
           Do not extend the key that contains a component
@@ -1815,19 +1816,20 @@ int TABLE_SHARE::init_from_binary_frm_image(THD *thd, bool write,
           if (share->field[fieldnr-1]->key_length() !=
               keyinfo->key_part[i].length)
 	  {
-            add_first_key_parts= 0;
+            add_keyparts_for_this_key= 0;
             break;
           }
         }
 
-        if (add_first_key_parts < keyinfo->ext_key_parts-keyinfo->user_defined_key_parts)
+        if (add_keyparts_for_this_key < (keyinfo->ext_key_parts -
+                                        keyinfo->user_defined_key_parts))
 	{
           share->ext_key_parts-= keyinfo->ext_key_parts;
           key_part_map ext_key_part_map= keyinfo->ext_key_part_map;
           keyinfo->ext_key_parts= keyinfo->user_defined_key_parts;
           keyinfo->ext_key_flags= keyinfo->flags;
 	  keyinfo->ext_key_part_map= 0; 
-          for (i= 0; i < add_first_key_parts; i++)
+          for (i= 0; i < add_keyparts_for_this_key; i++)
 	  {
             if (ext_key_part_map & 1<<i)
 	    {