MYSQL: log the query executed on certain table

Question

I am writing a trigger that suppose to fire on inserts for a table and log the exact query used to insert.

However, using below

SELECT info INTO original_query FROM INFORMATION_SCHEMA.PROCESSLIST WHERE id=CONNECTION_ID();

Always return in original_query variable this above query not the one firing the trigger and count in processlist is 1.

I am in MySQL 5.6.18.

This is the whole trigger deffinition

DROP TRIGGER IF EXISTS affiliate_revenue_i_log$$
CREATE TRIGGER affiliate_revenue_i_log BEFORE INSERT ON cds_affiliate_revenues
    FOR EACH ROW
    BEGIN
      DECLARE original_query VARCHAR(1024);        
      SELECT info INTO original_query FROM INFORMATION_SCHEMA.PROCESSLIST WHERE id=CONNECTION_ID();
      INSERT INTO cds_affiliate_revenues_log (action,id,added_date,original_query) VALUES('insert',NEW.id,NOW(),original_query);
    END$$

Answer 1

You could use log_output and general_log (USE CAREFUL), for those blessed with MySQL >= 5.1.12:

Steps:

I've created a new table called new_table:

CREATE TABLE new_table (
  id int(11) NOT NULL,
  text varchar(45) DEFAULT NULL,
  text2 varchar(45) DEFAULT NULL,
  PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

I've created a new log table called new_table_log:

CREATE TABLE test.new_table_log LIKE new_table;

ALTER TABLE test.new_table_log 
CHANGE COLUMN text2 text2 VARCHAR(1024) NULL DEFAULT NULL COMMENT '' ;

Trigger:

USE `test`;
DELIMITER $$
DROP TRIGGER IF EXISTS test.new_table_AFTER_INSERT$$
USE `test`$$
CREATE DEFINER=`root`@`localhost` TRIGGER `test`.`new_table_AFTER_INSERT` AFTER INSERT ON `new_table` FOR EACH ROW
BEGIN
    DECLARE vOriginal_query VARCHAR(1024); 
    DECLARE vLAST_LO VARCHAR(15) DEFAULT 'NONE';
    DECLARE vLAST_GL ENUM('ON','OFF') DEFAULT 'OFF';
    SET vLAST_LO=@@log_output;
    SET vLAST_GL=IF(@@general_log=0,'OFF','ON');
    SET GLOBAL log_output = 'TABLE';
    SET GLOBAL general_log = 'ON';
    SELECT argument INTO vOriginal_query FROM mysql.general_log WHERE argument LIKE 'INSERT%' AND argument NOT LIKE '%NEW.%' AND thread_id=CONNECTION_ID() ORDER BY event_time DESC LIMIT 0,1;
    INSERT INTO new_table_log(id,text,text2)VALUES(NEW.id,'INSERT',vOriginal_query);
    SET GLOBAL log_output = vLAST_LO;
    SET GLOBAL general_log = vLAST_GL;
END$$
DELIMITER ;

Insert into new_table:

INSERT INTO test.new_table(id,text,text2)VALUES(1,'Lel','TEST');

Test:

mysql> SELECT @@log_output;
+--------------+
| @@log_output |
+--------------+
| FILE         |
+--------------+
1 row in set (0.00 sec)

mysql> SELECT @@general_log;
+---------------+
| @@general_log |
+---------------+
|             0 |
+---------------+
1 row in set (0.00 sec)

mysql> CREATE TABLE new_table (
    ->   id int(11) NOT NULL,
    ->   text varchar(45) DEFAULT NULL,
    ->   text2 varchar(45) DEFAULT NULL,
    ->   PRIMARY KEY (id)
    -> ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Query OK, 0 rows affected (0.01 sec)

mysql> CREATE TABLE test.new_table_log LIKE new_table;
Query OK, 0 rows affected (0.01 sec)

mysql> ALTER TABLE test.new_table_log 
    -> CHANGE COLUMN text2 text2 VARCHAR(1024) NULL DEFAULT NULL COMMENT '' ;
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> INSERT INTO test.new_table(id,text,text2)VALUES(1,'Lel','TEST');
Query OK, 1 row affected (0.02 sec)

mysql> SELECT * FROM test.new_table;
+----+------+-------+
| id | text | text2 |
+----+------+-------+
|  1 | Lel  | TEST  |
+----+------+-------+
1 row in set (0.00 sec)

mysql> SELECT * FROM test.new_table_log;
+----+--------+-----------------------------------------------------------------+
| id | text   | text2                                                           |
+----+--------+-----------------------------------------------------------------+
|  1 | INSERT | INSERT INTO test.new_table(id,text,text2)VALUES(1,'Lel','TEST') |
+----+--------+-----------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT @@log_output;
+--------------+
| @@log_output |
+--------------+
| FILE         |
+--------------+
1 row in set (0.00 sec)

mysql> SELECT @@general_log;
+---------------+
| @@general_log |
+---------------+
|             0 |
+---------------+
1 row in set (0.00 sec)

mysql>