php 数据库连接性能问题
刚开始学习php,但是有个问题搞不明白
php是一个用户访问页面就与数据库建立一个连接,可是如果连接数比较大,那不是
性能很低吗。php里有类似连接池这个概念吗,就是分配一定数量的连接,然后重复
使用。求高手指教!
------解决方案--------------------
为什么连接数大就会性能低呢?
mysql默认连接数是100,就是说1个连接与100个连接的性能是一样的
apache默认连接数是150,除非你的网页中只是单一的数据查询(没有图片和外联样式表),才有可能出现150个访问中有50个排队(指150个用户在同一时刻发出请求)
连接池并不缓存数据库连接,他缓存的是到数据库服务器的网络连接
php虽然不提供连接池,但他提供了长连接用来缓存到数据库服务器的网络连接
注意,连接池并不是编程语言提供的,而是由第三方提供的应用软件:jdbc、odbc的附属功能

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