MariaDB:在存储过程锁定行中选择

隔离级别为只读提交,引擎为InnoDB,因此所有select应为非锁定一致读取: https://dev.mysql.com/doc/refman/8.0/en/innodb-consistent-read.html

数据库为MariaDB版本10.1:

MariaDB [(none)]> select @@version;
+-----------------+
| @@version       |
+-----------------+
| 10.1.24-MariaDB |
+-----------------+
1 row in set (0.02 sec)

以下选择存储过程锁获取表上的锁 agent :

IF 
    v_pack_agent_id IS NULL OR 
    v_pack_agent_id not in                  
    (
        select ID from agent where LINKED_AGENTS_GUID = (select LINKED_AGENTS_GUID from agent where ID = a_agent_id) union all 
        select a_agent_id
    )
THEN
    SET a_sign = SIGN_NOT_OWN_BLOCK;
    LEAVE l_proc;
END IF;

桌子 代理人 定义:

MariaDB [db_mercury]> show create table agent\G
*************************** 1. row ***************************
Table: agent
Create Table: CREATE TABLE `agent` (
`ID` smallint(5) unsigned NOT NULL AUTO_INCREMENT COMMENT 'PK',
 ...
`LINKED_AGENTS_GUID` varchar(64) COLLATE utf8_unicode_ci DEFAULT NULL,
 PRIMARY KEY (`ID`),
 UNIQUE KEY `UK$ORA_ID` (`ORA_ID`),
 KEY `IDX_LINKED_AGENTS_GUID` (`LINKED_AGENTS_GUID`)
 ) ENGINE=InnoDB AUTO_INCREMENT=6198 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

问题是因为选择嵌套在 IF 如果 如下图所示,则不会获取锁。

这不会锁定任何内容:

select ID 
from agent 
where LINKED_AGENTS_GUID = (select LINKED_AGENTS_GUID 
                            from agent 
                            where ID = a_agent_id) 
union all 
select a_agent_id

对我来说,这就像一只虫子。