wordpress主题破解网站,博山网站建设,做网站文案,wordpress分页#xff08;待更新整理#xff09; 因为最近遇到一些超时的问题#xff0c;正好就把所有的timeout参数都理一遍#xff0c;首先数据库里查一下看有哪些超时#xff1a; rootlocalhost : test 12:55:50 show global variables like %timeout%;
-----------…待更新整理 因为最近遇到一些超时的问题正好就把所有的timeout参数都理一遍首先数据库里查一下看有哪些超时 rootlocalhost : test 12:55:50 show global variables like %timeout%;
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| Variable_name | Value |
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| connect_timeout | 10 |
| delayed_insert_timeout | 300 |
| innodb_lock_wait_timeout | 120 |
| innodb_rollback_on_timeout | ON |
| interactive_timeout | 172800 |
| net_read_timeout | 30 |
| net_write_timeout | 60 |
| slave_net_timeout | 3600 |
| table_lock_wait_timeout | 50 | # 这个参数已经没用了
| wait_timeout | 172800 |
------------------------------------ 我们一个个来看 目录 (Contents) [隐藏 (Hide)] 1 connect_timeout2 delayed_insert_timeout3 innodb_lock_wait_timeout4 innodb_rollback_on_timeout5 interactive_timeout/wait_timeout6 net_read_timeout / net_write_timeout7 slave_net_timeout connect_timeout 手册描述:The number of seconds that the mysqld server waits for a connect packet before responding with Bad handshake. The default value is 10 seconds as of MySQL 5.1.23 and 5 seconds before that.Increasing the connect_timeout value might help if clients frequently encounter errors of the form Lost connection to MySQL server at ‘XXX’, system error: errno.解释在获取链接时等待握手的超时时间只在登录时有效登录成功这个参数就不管事了。主要是为了防止网络不佳时应用重连导致连接数涨太快一般默认即可。 delayed_insert_timeout 手册描述How many seconds an INSERT DELAYED handler thread should wait for INSERT statements before terminating.解释这是为MyISAM INSERT DELAY设计的超时参数在INSERT DELAY中止前等待INSERT语句的时间。 innodb_lock_wait_timeout 手册描述The timeout in seconds an InnoDB transaction may wait for a row lock before giving up. The default value is 50 seconds. A transaction that tries to access a row that is locked by another InnoDB transaction will hang for at most this many seconds before issuing the following error: ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction When a lock wait timeout occurs, the current statement is not executed. The current transaction is not rolled back. (To have the entire transaction roll back, start the server with the –innodb_rollback_on_timeout option, available as of MySQL 5.1.15. See also Section 13.6.12, “InnoDB Error Handling”.)innodb_lock_wait_timeout applies to InnoDB row locks only. A MySQL table lock does not happen inside InnoDB and this timeout does not apply to waits for table locks.InnoDB does detect transaction deadlocks in its own lock table immediately and rolls back one transaction. The lock wait timeout value does not apply to such a wait.For the built-in InnoDB, this variable can be set only at server startup. For InnoDB Plugin, it can be set at startup or changed at runtime, and has both global and session values.解释描述很长简而言之就是事务遇到锁等待时的Query超时时间。跟死锁不一样InnoDB一旦检测到死锁立刻就会回滚代价小的那个事务锁等待是没有死锁的情况下一个事务持有另一个事务需要的锁资源被回滚的肯定是请求锁的那个Query。 innodb_rollback_on_timeout 手册描述In MySQL 5.1, InnoDB rolls back only the last statement on a transaction timeout by default. If –innodb_rollback_on_timeout is specified, a transaction timeout causes InnoDB to abort and roll back the entire transaction (the same behavior as in MySQL 4.1). This variable was added in MySQL 5.1.15.解释这个参数关闭或不存在的话遇到超时只回滚事务最后一个Query打开的话事务遇到超时就回滚整个事务。 interactive_timeout/wait_timeout 手册描述The number of seconds the server waits for activity on an interactive connection before closing it. An interactive client is defined as a client that uses the CLIENT_INTERACTIVE option to mysql_real_connect(). See also解释一个持续SLEEP状态的线程多久被关闭。线程每次被使用都会被唤醒为acrivity状态执行完Query后成为interactive状态重新开始计时。wait_timeout不同在于只作用于TCP/IP和Socket链接的线程意义是一样的。 net_read_timeout / net_write_timeout 手册描述The number of seconds to wait for more data from a connection before aborting the read. Before MySQL 5.1.41, this timeout applies only to TCP/IP connections, not to connections made through Unix socket files, named pipes, or shared memory. When the server is reading from the client, net_read_timeout is the timeout value controlling when to abort. When the server is writing to the client, net_write_timeout is the timeout value controlling when to abort. See also slave_net_timeout.On Linux, the NO_ALARM build flag affects timeout behavior as indicated in the description of the net_retry_count system variable.解释这个参数只对TCP/IP链接有效分别是数据库等待接收客户端发送网络包和发送网络包给客户端的超时时间这是在Activity状态下的线程才有效的参数 slave_net_timeout 手册描述The number of seconds to wait for more data from the master before the slave considers the connection broken, aborts the read, and tries to reconnect. The first retry occurs immediately after the timeout. The interval between retries is controlled by the MASTER_CONNECT_RETRY option for the CHANGE MASTER TO statement or –master-connect-retry option, and the number of reconnection attempts is limited by the –master-retry-count option. The default is 3600 seconds (one hour).解释这是Slave判断主机是否挂掉的超时设置在设定时间内依然没有获取到Master的回应就人为Master挂掉了 【参考资料】 1、http://www.penglixun.com/tech/database/mysql_timeout.html 2、http://www.ttlsa.com/mysql/research-and-measurement-of-timeout-mysql/转载于:https://www.cnblogs.com/gsblog/p/4046526.html
