把table_cache适当调小mysql能更快地工作_MySQL
在我们的意识里,通常增大table_cache,尽量使打开的表句柄在缓存中,mysql能更快地响应操作,但是当我增大table_cache后,cpu增大了很多,查资料发现,table_cache并不是越大越好,因为mysql只有一个全局锁来控制打开和关闭表,也就是说无论有多少个线程在并行执行,只有一个线程可以打开或关闭表,这也就会出现很多死锁,别的线程等待那个全局锁,相应地增加了cpu的消耗,延长了其他链接线程执行sql的时间,降低系统性能,所以在保证table_cache够用的情况下,尽量保持table_cache足够小,但是这个度怎么把握,我也没有一定的尺度,还得再学习。
参考资料:
关于table_cache
table_cache的副作用
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