查看innodb_buffer_pool_size大小，字节显示

SHOW VARIABLES LIKE 'innodb_buffer_pool_size';

要将 innodb_buffer_pool_size 的值从字节转换为 MB，可以使用以下 SQL 查询：

SELECT CONCAT(ROUND((@@innodb_buffer_pool_size / (1024*1024)), 2), 'MB') AS innodb_buffer_pool_size_MB;

查看buffer_pool_unused使用率

SELECT

    CONCAT(ROUND((1 - SUM(IF(free_page_clock > 0, 1, 0)) / COUNT(*)) * 100, 2), '%') AS buffer_pool_used,

    CONCAT(ROUND(SUM(free_page_clock) / 1000000, 2), 'MB') AS buffer_pool_unused

FROM

    INFORMATION_SCHEMA.INNODB_BUFFER_PAGE_LRU;