《Mysql必读Mysql 错误too many connections解决方案》要点：
本文介绍了Mysql必读Mysql 错误too many connections解决方案，希望对您有用。如果有疑问，可以联系我们。
Mysql 错误提示too many connections,最近遇到这个错误,经过上网查资料解决了,这里记录下,帮助有需要的朋友,MYSQL学习
解决方法是修改/etc/mysql/my.cnf,添加以下一行:MYSQL学习
set-variable = max_connections=500MYSQL学习
或在启动命令中加上参数 max_connections=500MYSQL学习
就是修改最大连接数,然后重启mysql.默认的连接数是100,太少了,所以容易出现如题错误.MYSQL学习
以下是mysql.com网站的相关说明:MYSQL学习
If you get a Too many connections error when you try to connect to the mysqld server, this means that all available connections are in use by other clients.MYSQL学习
The number of connections allowed is controlled by the max_connections system variable. Its default value is 100. If you need to support more connections, you should restart mysqld with a larger value for this variable.MYSQL学习
mysqld actually allows max_connections+1 clients to connect. The extra connection is reserved for use by accounts that have the SUPER privilege. By granting the SUPER privilege to administrators and not to normal users (who should not need it), an administrator can connect to the server and use SHOW PROCESSLIST to diagnose problems even if the maximum number of unprivileged clients are connected. See Section 13.5.4.19, “SHOW PROCESSLIST Syntax”.MYSQL学习
The maximum number of connections MySQL can support depends on the quality of the thread library on a given platform. Linux or Solaris should be able to support 500-1000 simultaneous connections, depending on how much RAM you have and what your clients are doing. Static Linux binaries provided by MySQL AB can support up to 4000 connections.MYSQL学习
1.可能是mysql的max connections设置的问题MYSQL学习
2.可能是多次insert,update操作没有关闭session,需要在spring里配置transaction支持.MYSQL学习
解决:MYSQL学习
1.修改tomcat里的session 的time-out时间减少为20,(不是必改项)MYSQL学习
2.对处理量大的对数据库insert或update的操作提供transaction支持.MYSQL学习
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下面的是解决办法：MYSQL学习
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: "Too many connections"MYSQL学习
原因：MYSQL学习
因为你的mysql安装目录下的my.ini中设定的并发连接数太少或者系统繁忙导致连接数被占满MYSQL学习
解决方式：MYSQL学习
打开MYSQL安装目录打开MY.INI找到max_connections(在大约第93行)默认是100 一般设置到500～1000比较合适,重启mysql,这样1040错误就解决啦.MYSQL学习
max_connections=1000MYSQL学习
一定要重新启动MYSQL才能生效MYSQL学习
CMD->MYSQL学习
net stop mysqlMYSQL学习
net start mysqlMYSQL学习
关于改变innodb_log_file_size后无法启动mysql的问题MYSQL学习
innodb_buffer_pool_size=768M innodb_log_file_size=256M innodb_log_buffer_size=8M innodb_additional_mem_pool_size=4M innodb_flush_log_at_trx_commit=0 innodb_thread_concurrency=20
以上是对innodb引擎的初步优化, 发现是更新innodb_log_file_size=256M时候出现了问题,只要加上这个就无法启动,MYSQL学习
后来才知道原来要STOP服务先,然后再删除原来的文件………MYSQL学习
打开/MySQL Server 5.5/dataMYSQL学习
删除ib_logfile0, ib_logfile1........ib_logfilenMYSQL学习
再开启选项,成功启动.MYSQL学习
感谢阅读,希望能帮助到大家,谢谢大家对本站的支持!MYSQL学习
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