Better fix for bug #3749 (bug in deleting automatic generated foreign keys)

mysql-test/r/func_encrypt.result

@@ -138,4 +138,4 @@ explain extended select des_decrypt(des_encrypt("hello",4),'password2'), des_dec
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
-Note	1003	select high_priority des_decrypt(des_encrypt(_latin1'hello',4),_latin1'password2') AS `des_decrypt(des_encrypt("hello",4),'password2')`,des_decrypt(des_encrypt(_latin1'hello',_latin1'hidden')) AS `des_decrypt(des_encrypt("hello","hidden"))`
+Note	1003	select des_decrypt(des_encrypt(_latin1'hello',4),_latin1'password2') AS `des_decrypt(des_encrypt("hello",4),'password2')`,des_decrypt(des_encrypt(_latin1'hello',_latin1'hidden')) AS `des_decrypt(des_encrypt("hello","hidden"))`

mysql-test/r/innodb.result

@@ -1538,6 +1538,37 @@ t2	CREATE TABLE `t2` (
   CONSTRAINT `t1_id_fk` FOREIGN KEY (`id2`, `id`) REFERENCES `t1` (`id`, `id2`)
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1
 drop table t2;
+create table t2 (id int(11) not null auto_increment, id2 int(11) not null, constraint t1_id_fk foreign key (id) references t1 (id), primary key (id), index (id,id2)) engine = innodb;
+show create table t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `id` int(11) NOT NULL auto_increment,
+  `id2` int(11) NOT NULL default '0',
+  PRIMARY KEY  (`id`),
+  KEY `id` (`id`,`id2`),
+  CONSTRAINT `t1_id_fk` FOREIGN KEY (`id`) REFERENCES `t1` (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+drop table t2;
+create table t2 (id int(11) not null auto_increment, id2 int(11) not null, constraint t1_id_fk foreign key (id) references t1 (id)) engine= innodb;
+show create table t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `id` int(11) NOT NULL auto_increment,
+  `id2` int(11) NOT NULL default '0',
+  KEY `t1_id_fk` (`id`),
+  CONSTRAINT `t1_id_fk` FOREIGN KEY (`id`) REFERENCES `t1` (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+alter table t2 add index id_test (id), add index id_test2 (id,id2);
+show create table t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `id` int(11) NOT NULL auto_increment,
+  `id2` int(11) NOT NULL default '0',
+  KEY `id_test` (`id`),
+  KEY `id_test2` (`id`,`id2`),
+  CONSTRAINT `t1_id_fk` FOREIGN KEY (`id`) REFERENCES `t1` (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+drop table t2;
 create table t2 (id int(11) not null, id2 int(11) not null, constraint t1_id_fk foreign key (id2,id) references t1 (id)) engine = innodb;
 ERROR HY000: Can't create table './test/t2.frm' (errno: 150)
 drop table t1;

mysql-test/t/innodb.test

@@ -1082,6 +1082,16 @@ create table t2 (id int(11) not null, id2 int(11) not null, unique (id,id2),cons
 show create table t2;
 drop table t2;
 
+create table t2 (id int(11) not null auto_increment, id2 int(11) not null, constraint t1_id_fk foreign key (id) references t1 (id), primary key (id), index (id,id2)) engine = innodb;
+show create table t2;
+drop table t2;
+
+create table t2 (id int(11) not null auto_increment, id2 int(11) not null, constraint t1_id_fk foreign key (id) references t1 (id)) engine= innodb;
+show create table t2;
+alter table t2 add index id_test (id), add index id_test2 (id,id2);
+show create table t2;
+drop table t2;
+
 # Test error handling
 --error 1005
 create table t2 (id int(11) not null, id2 int(11) not null, constraint t1_id_fk foreign key (id2,id) references t1 (id)) engine = innodb;

sql/sql_class.cc

@@ -86,7 +86,7 @@ bool key_part_spec::operator==(const key_part_spec& other) const
 
 
 /*
-  Test if a foreign key is a prefix of the given key
+  Test if a foreign key (= generated key) is a prefix of the given key
   (ignoring key name, key type and order of columns)
 
   NOTES:

sql/sql_table.cc

@@ -684,11 +684,13 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
       while ((key2 = key_iterator2++) != key)
       {
 	/*
-        foreign_key_prefix(key, key2) returns 0 if key or key2, or both, is
-	'generated', and a generated key is a prefix of the other key. Then we
-	do not need the generated shorter key.
+          foreign_key_prefix(key, key2) returns 0 if key or key2, or both, is
+          'generated', and a generated key is a prefix of the other key.
+          Then we do not need the generated shorter key.
         */
-        if ((key2->type != Key::FOREIGN_KEY && !foreign_key_prefix(key, key2)))
+        if ((key2->type != Key::FOREIGN_KEY &&
+             key2->name != ignore_key &&
+             !foreign_key_prefix(key, key2)))
         {
           /* TO DO: issue warning message */
           /* mark that the generated key should be ignored */
@@ -698,17 +700,9 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
             key->name= ignore_key;
           else
           {
-            /*
-	    Remove the previous, generated key if it has not yet been
-	    removed. Note that if we have several identical generated keys,
-            the last one will remain and others get removed here.
-	    */
-            if (key2->name != ignore_key)
-            {
-              key2->name= ignore_key;
-              key_parts-= key2->columns.elements;
-              (*key_count)--;
-            }
+            key2->name= ignore_key;
+            key_parts-= key2->columns.elements;
+            (*key_count)--;
           }
           break;
         }

tests/client_test.c

@@ -9614,7 +9614,6 @@ union distinct \
 select sum(a) + 200, 1 from t1 \
 group by b ");
   check_stmt(stmt);
-
   mysql_stmt_close(stmt);
 
  stmt= mysql_simple_prepare(mysql,
@@ -9624,14 +9623,14 @@ union distinct \
 select sum(a) + 200, 1 from t1 \
 group by b ");
   check_stmt(stmt);
+  mysql_stmt_close(stmt);
 
- stmt= mysql_simple_prepare(mysql,
+  stmt= mysql_simple_prepare(mysql,
 			     "select sum(a) + 200, ? from t1 \
 union distinct \
 select sum(a) + 200, 1 from t1 \
 group by b ");
   check_stmt(stmt);
-
   mysql_stmt_close(stmt);
 
   rc= mysql_query(mysql, "DROP TABLE t1");