mysql innodb 命中率

SELECT
( SELECT variable_value FROM PERFORMANCE_SCHEMA.global_status WHERE variable_name = 'Innodb_buffer_pool_read_requests' ) / (
SELECT
SUM( variable_value )
FROM
PERFORMANCE_SCHEMA.global_status
WHERE
variable_name IN ( 'Innodb_buffer_pool_read_requests', 'Innodb_buffer_pool_read_ahead', 'Innodb_buffer_pool_reads' )
)

命中率低于99% ，需要扩innodb_buffer_pool_size大小