CREATE TABLE test ( id INT NOT NULL, last_name CHAR(30) NOT NULL, first_name CHAR(30) NOT NULL, PRIMARY KEY (id), INDEX name (last_name,first_name) );
以上创建的其实是一个多列索引,创建列索引的代码如下:
CREATE TABLE test ( id INT NOT NULL, last_name CHAR(30) NOT NULL, first_name CHAR(30) NOT NULL, PRIMARY KEY (id), INDEX name (last_name), INDEX_2 name (first_name) );
SELECT * FROM test WHERE last_name='Widenius'; SELECT * FROM test WHERE last_name='Widenius' AND first_name='Michael'; SELECT * FROM test WHERE last_name='Widenius' AND (first_name='Michael' OR first_name='Monty'); SELECT * FROM test WHERE last_name='Widenius' AND first_name >='M' AND first_name <'N';
以下形式的查询语句利用不上多列索引:
SELECT * FROM test WHERE first_name='Michael'; SELECT * FROM test WHERE last_name='Widenius' OR first_name='Michael';
本文描述了mysql-cluster集群sql节点高可用keepalived的故障处理过程,包括故障发生时间、故障描述、故障分析等内容。根据keepalived的日志分析,发现bogus VRRP packet received on eth0 !!!等错误信息,进而导致vip地址失效,使得mysql-cluster的api无法访问。针对这个问题,本文提供了相应的解决方案。 ...
[详细]