###第九部分:MySQL索引使用情况
###索引使用情况
SELECT
object_type,object_schema,object_name,index_name,
count_read,count_fetch, count_insert,
count_update,count_delete
FROM
performance_schema.table_io_waits_summary_by_index_usage
ORDER BY
sum_timer_wait DESC;
#索引重新统计
ANALYZE TABLE exam_student_subjective_fileurl_51_2019_10;
#optimize 优化表空间,释放表空间
#锁表,一定要在维护期间,否则会造成IO阻塞
OPTIMIZE TABLE exam_student_subjective_fileurl_51_2019_10;