<span>Innodb_buffer_pool_read</span>
> show status like 'Innodb_buffer_pool_read_%'; +---------------------------------------+--------------+ | Variable_name | Value | +---------------------------------------+--------------+ | Innodb_buffer_pool_read_ahead_rnd | 0 | | Innodb_buffer_pool_read_ahead | 115434683 | | Innodb_buffer_pool_read_ahead_evicted | 0 | | Innodb_buffer_pool_read_requests | 113290429682 | | Innodb_buffer_pool_reads | 4372247 | +---------------------------------------+--------------+ 5 rows in set (0.00 sec) Thu Oct 24 09:32:55 2019 >
Innodb_buffer_pool_read_requests表示read请求的次数，
Innodb_buffer_pool_reads表示从物理磁盘中读取数据的请求次数，
所以innodb buffer的read命中率就可以这样得到：（Innodb_buffer_pool_read_requests - Innodb_buffer_pool_reads） / Innodb_buffer_pool_read_requests * 100%。
一般来讲这个命中率不会低于99%，如果低于这个值的话就要考虑加大innodb buffer pool，大家通常建议设置为系统内存的50%-80%
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