Bug#25721

  "Concurrent ALTER/CREATE SERVER can lead to deadlock"
  Deadlock caused by inconsistant use of mutexes in sql_server.cc
  One mutex has been removed to resolve deadlock.
  Many functions were made private which should not be exported.
  Unused variables and function removed.

mysql-test/r/federated_server.result

@@ -189,6 +189,31 @@ drop user guest_select@localhost;
 drop table federated.t1;
 drop server 's1';
 # End of 5.1 tests
+use test;
+create procedure p1 ()
+begin
+DECLARE v INT DEFAULT 0;
+DECLARE e INT DEFAULT 0;
+DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET e = e + 1;
+WHILE v < 10000 do
+CREATE SERVER s
+FOREIGN DATA WRAPPER mysql
+OPTIONS (USER 'Remote', HOST '192.168.1.106', DATABASE 'test');
+ALTER SERVER s OPTIONS (USER 'Remote');
+DROP SERVER s;
+SET v = v + 1;
+END WHILE;
+SELECT e > 0;
+END//
+use test;
+call p1();
+call p1();
+e > 0
+1
+e > 0
+1
+drop procedure p1;
+drop server if exists s;
 DROP TABLE IF EXISTS federated.t1;
 DROP DATABASE IF EXISTS federated;
 DROP TABLE IF EXISTS federated.t1;

mysql-test/t/federated_server.test

@@ -234,4 +234,39 @@ drop server 's1';
 
 --echo # End of 5.1 tests
 
+
+#
+# Bug#25721 - deadlock with ALTER/CREATE SERVER
+#
+connect (other,localhost,root,,);
+connection master;
+use test;
+delimiter //;
+create procedure p1 ()
+begin
+  DECLARE v INT DEFAULT 0;
+  DECLARE e INT DEFAULT 0;
+  DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET e = e + 1;
+  WHILE v < 10000 do
+    CREATE SERVER s
+      FOREIGN DATA WRAPPER mysql
+      OPTIONS (USER 'Remote', HOST '192.168.1.106', DATABASE 'test');
+    ALTER SERVER s OPTIONS (USER 'Remote');
+	DROP SERVER s;
+    SET v = v + 1;
+  END WHILE;
+  SELECT e > 0;
+END//
+delimiter ;//
+connection other;
+use test;
+send call p1();
+connection master;
+call p1();
+connection other;
+reap;
+drop procedure p1;
+drop server if exists s;
+
+
 source include/federated_cleanup.inc;

sql/sql_parse.cc

@@ -4320,7 +4320,7 @@ mysql_execute_command(THD *thd)
 
     if ((err_code= drop_server(thd, &lex->server_options)))
     {
-      if (! lex->drop_if_exists && err_code == ER_FOREIGN_SERVER_EXISTS)
+      if (! lex->drop_if_exists && err_code == ER_FOREIGN_SERVER_DOESNT_EXIST)
       {
         DBUG_PRINT("info", ("problem dropping server %s",
                             lex->server_options.server_name));

sql/sql_servers.h

@@ -25,40 +25,18 @@ typedef struct st_federated_server
 } FOREIGN_SERVER;
 
 /* cache handlers */
-my_bool servers_init(bool dont_read_server_table);
-my_bool servers_reload(THD *thd);
-my_bool get_server_from_table_to_cache(TABLE *table);
+bool servers_init(bool dont_read_server_table);
+bool servers_reload(THD *thd);
 void servers_free(bool end=0);
 
 /* insert functions */
 int create_server(THD *thd, LEX_SERVER_OPTIONS *server_options);
-int insert_server(THD *thd, FOREIGN_SERVER *server_options);
-int insert_server_record(TABLE *table, FOREIGN_SERVER *server);
-int insert_server_record_into_cache(FOREIGN_SERVER *server);
-void store_server_fields_for_insert(TABLE *table, FOREIGN_SERVER *server);
-void store_server_fields_for_insert(TABLE *table,
-                                    FOREIGN_SERVER *existing,
-                                    FOREIGN_SERVER *altered);
-int prepare_server_struct_for_insert(LEX_SERVER_OPTIONS *server_options,
-                                     FOREIGN_SERVER *server);
 
 /* drop functions */ 
 int drop_server(THD *thd, LEX_SERVER_OPTIONS *server_options);
-int delete_server_record(TABLE *table,
-                         char *server_name,
-                         int server_name_length);
-int delete_server_record_in_cache(LEX_SERVER_OPTIONS *server_options);
 
 /* update functions */
 int alter_server(THD *thd, LEX_SERVER_OPTIONS *server_options);
-int prepare_server_struct_for_update(LEX_SERVER_OPTIONS *server_options,
-                                     FOREIGN_SERVER *existing,
-                                     FOREIGN_SERVER *altered);
-int update_server(THD *thd, FOREIGN_SERVER *existing, FOREIGN_SERVER *altered);
-int update_server_record(TABLE *table, FOREIGN_SERVER *server);
-int update_server_record_in_cache(FOREIGN_SERVER *existing,
-                                  FOREIGN_SERVER *altered);
-/* utility functions */
-void merge_server_struct(FOREIGN_SERVER *from, FOREIGN_SERVER *to);
+
+/* lookup functions */
 FOREIGN_SERVER *get_server_by_name(const char *server_name);
-my_bool server_exists_in_table(THD *thd, char *server_name);