记录原因：今天在一个mysql更新语句的执行过程中，总是执行超时，后来查到原因是因为有一个事务没有关闭，导致那条记录的查询和更新都会执行超时
以下的SQL语句可以查询当前数据库， 有哪些事务，都锁定哪些资源
SELECT trx_id AS `事务ID`, trx_state AS `事务状态`, trx_requested_lock_id AS `事务需要等待的资源`, trx_wait_started AS `事务开始等待时间`, trx_tables_in_use AS `事务使用表`, trx_tables_locked AS `事务拥有锁`, trx_rows_locked AS `事务锁定行`, trx_rows_modified AS `事务更改行` FROM information_schema.innodb_trx ; SELECT lock_id AS `锁ID`, lock_trx_id AS `拥有锁的事务ID`, lock_mode AS `锁模式 `, lock_type AS `锁类型`, lock_table AS `被锁的表`, lock_index AS `被锁的索引`, lock_space AS `被锁的表空间号`, lock_page AS `被锁的页号`, lock_rec AS `被锁的记录号`, lock_data AS `被锁的数据` FROM information_schema.innodb_locks; SELECT requesting_trx_id AS `请求锁的事务ID`, requested_lock_id AS `请求锁的锁ID`, blocking_trx_id AS `当前拥有锁的事务ID`, blocking_lock_id AS `当前拥有锁的锁ID` FROM information_schema.innodb_lock_waits;代码转自：奋斗熊的博客
