我今天遇到了同样的问题,每次触发都会导致堆栈溢出.原来我的Zend社区服务器安装附带了一个默认的my.cnf文件,其中thread_stack大小设置为128K,这导致每个线程中可用于堆栈的131072字节:
mysql> show variables where `Variable_name` = 'thread_stack';
+---------------+--------+
| Variable_name | Value |
+---------------+--------+
| thread_stack | 131072 |
+---------------+--------+
所以我在/usr/local/zend/mysql/data/my.cnf中注释了这一行,重新启动了mysql守护进程,瞧! default 192K是
mysql> show variables where `Variable_name` = 'thread_stack';
+---------------+--------+
| Variable_name | Value |
+---------------+--------+
| thread_stack | 196608 |
+---------------+--------+
现在你的桌子& tchester的触发器工作完美:)(尽管请注意分隔符)
mysql> CREATE TABLE `job_title` (
-> `job_id` int(11) NOT NULL AUTO_INCREMENT,
-> `position_id` int(11) DEFAULT NULL,
-> `title` varchar(255) COLLATE latin1_general_cs NOT NULL,
-> `selectable` tinyint(4) NOT NULL DEFAULT '0',
-> PRIMARY KEY (`job_id`),
-> UNIQUE KEY `title` (`title`)
-> ) ENGINE=InnoDB;
Query OK, 0 rows affected (0.14 sec)
mysql> DELIMITER &&
mysql> create trigger job_position_trigger
-> before insert on job_title for each row
-> begin
-> if new.position_id is null then
-> set @position = (select max(position_id)+1 from job_title);
-> if @position is null then set @position = 1; end if;
-> set new.position_id = @position;
-> end if;
-> end;
-> &&
Query OK, 0 rows affected (0.29 sec)
mysql> DELIMITER ;
mysql> insert into job_title (title, selectable) values ("test", 1);
Query OK, 1 row affected (0.00 sec)
mysql> insert into job_title (title, selectable) values ("test2", 3);
Query OK, 1 row affected (0.00 sec)
mysql> select * from job_title;
+--------+-------------+-------+------------+
| job_id | position_id | title | selectable |
+--------+-------------+-------+------------+
| 1 | 1 | test | 1 |
| 2 | 2 | test2 | 3 |
+--------+-------------+-------+------------+
2 rows in set (0.00 sec)
你得到的错误,131072字节堆栈使用的9024字节和所需的128000字节是有意义的:9024 128000> 131072.