The locks are normally next-key locks that also block inserts into the "gap" immediately before the record. mysql> select @@tx_isolation; +-----------------+ | @@tx_isolation | +-----------------+ | REPEATABLE-READ | +-----------------+ 1 row
删除索引~ DROP INDEX `idx_dict_type` ON `article` 1.添加PRIMARY KEY(主键索引): ALTER TABLE `table_name` ADD PRIMARY KEY (`column`) 2.添加UNIQUE(唯一索引) : ALTER TABLE `table_name` ADD UNIQUE (`column`) 3.添加INDEX(普通索引) : ALTER TABLE `table_name` ADD INDEX index_name
1.使用相同索引键值的冲突 由于mysql 的行锁是针对索引加的锁,不是针对记录加的锁,所以虽然是访问不同行的记录,但如果是使用相同的索引键,是会出现锁冲突的.设计时要注意 例如:city表city_id字段有索引,Cityname字段没有索引: 会话1 会话2 SET autocommit=0; SET autocommit=0; SELECT * FROM city WHERE city_id=14 AND Cityname='深圳' FOR UPDATE; city_id cou