MySQL UDF sys_exec() doesn't work

问题:

I have a trigger which calls a stored procedure with parameters which calls SET result = sys_exec(cmd);. But it gives the error "function sys_exec does not exist".

I don't know what to do, on Tuesday I have presentation and because of this code line my project won't work. The codes which I try to work.

DELIMITER $$
CREATE PROCEDURE push_message
(p1   int,
 p2   int,
 p3 varchar(20))
BEGIN
 DECLARE cmd CHAR(255);
 DECLARE result CHAR(255);
 SET cmd = CONCAT('curl https://pubsub.pubnub.com/publish/demo/demo/0/mysql_triggers/0/%22',p1, ',' ,p2, ',' ,p3,'%22');
 SET result = sys_exec(cmd);
END$$; 


CREATE TRIGGER push_message_trigger AFTER INSERT ON your_table_name_here
FOR EACH ROW
CALL push_message(NEW.id, NEW.num, NEW.name);

回答1:

Try:

mysql> SELECT VERSION();
+-----------------+
| VERSION()       |
+-----------------+
| 5.5.35-1ubuntu1 |
+-----------------+
1 row in set (0.00 sec)

mysql> SHOW VARIABLES LIKE 'plugin_dir';
+---------------+------------------------+
| Variable_name | Value                  |
+---------------+------------------------+
| plugin_dir    | /usr/lib/mysql/plugin/ | -- copy 'lib_mysqludf_sys.so' here
+---------------+------------------------+
1 row in set (0.01 sec)

mysql> DROP FUNCTION IF EXISTS lib_mysqludf_sys_info;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> DROP FUNCTION IF EXISTS sys_get;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> DROP FUNCTION IF EXISTS sys_set;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> DROP FUNCTION IF EXISTS sys_exec;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> DROP FUNCTION IF EXISTS sys_eval;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> CREATE FUNCTION lib_mysqludf_sys_info RETURNS string SONAME 'lib_mysqludf_sys.so';
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE FUNCTION sys_get RETURNS string SONAME 'lib_mysqludf_sys.so';
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE FUNCTION sys_set RETURNS int SONAME 'lib_mysqludf_sys.so';
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE FUNCTION sys_exec RETURNS int SONAME 'lib_mysqludf_sys.so';
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE FUNCTION sys_eval RETURNS string SONAME 'lib_mysqludf_sys.so';
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT sys_exec('curl http://stackoverflow.com/');
+--------------------------------------------+
| sys_exec('curl http://stackoverflow.com/') |
+--------------------------------------------+
|                                          0 |
+--------------------------------------------+
1 row in set (0.12 sec)

For more details, visit: 24.3.2.5 Compiling and Installing User-Defined Functions.

回答2:

Try Once.

Steps to be followed:

• Get the files from https://github.com/mysqludf/lib_mysqludf_sys

• Go to the folder path in terminal.

• Execute:

  gcc -DMYSQL_DYNAMIC_PLUGIN -fPIC -Wall -m64 -I/usr/include/mysql -I. -shared lib_mysqludf_sys.c -o lib_mysqludf_sys.so
  

  NOTE: If 32-bit OS replace -m64 with -m32 in the above command.

• Execute the following in mysql shell:

  SHOW VARIABLES LIKE 'plugin_dir';
  

  This is an example of successful output:

  +---------------+------------------------+
  | Variable_name | Value                  |
  +---------------+------------------------+
  | plugin_dir    | /usr/lib/mysql/plugin/ |
  +---------------+------------------------+
  

• Copy the lib_mysqludf_sys.so file to the above path.

• Execute the following in mysql shell

  CREATE FUNCTION sys_exec RETURNS INT SONAME 'lib_mysqludf_sys.so';