公司最近有個deployment，要run個SQL patch。係QA 同staging 都冇事，點知一去production run左30mins 都未行完，terminated & rollback. 原來係其中一個update statement 行subquery，where id = (select …) mysql 會run select on each row 🙁 DataSet 一大，慢到嘔。 CREATE TABLE alarm_backup SELECT * FROM alarm; UPDATE alarm a SET a.status = ‘active’ , ……. WHERE a.id = ( SELECT al.id FROM alarm_backup ab JOIN device d ON ab.device_id = …
http://mysql.chinahtml.com/2005/1125321683.shtml MySQL — inline edit chinese character 1. stop MySQL service 2. open my.ini 3. change default-character-set of [mysqld] and [client] as utf8 4. launch mysql 5. create table as default or select tuf8 6. enjoy ~
A. background OS: CentOS 4.4 MySQL package: 4.1.20-1.RHEL4.1 node1: 192.168.0.131 (Master 1/Slave 2) node2: 192.168.0.132 (Master 2/Slave 1) mysql path: /var/lib/mysql mysql config file: /etc/my.cnf reference: http://www.howtoforge.com/mysql_master_master_replication http://cha.homeip.net/blog/archives/2004/12/replication_in.html B. procedure 1. On Master 1, make changes in my.cnf #vim /etc/my.cnf [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock # Default to using old password format for compatibility with mysql …