查看执行最频繁TOP SQL：

可以解决问题：
1.SQL的执行次数
2.全表扫描
3.临时表

select digest_text as sql_text,count_star as exec_count,if(sum_no_good_index_used > 0 or sum_no_index_used > 0, '*', '') as full_scan,sum_created_tmp_tables as tmp_tables,
        sum_created_tmp_disk_tables as tmp_disk_tables,
        sum_sort_rows as rows_sorted from events_statements_summary_by_digest where schema_name='ticket' and digest_text like 'select%' order by count_star desc limit 10;


生成mysql sql 执行性能报告
开启SQL的性能收集
use performance_schema;
update setup_consumers set enabled='YES' where name IN ('events_statements_history','events_statements_current','statements_digest');
清空SQL性能数据
truncate table events_statements_current; 
truncate table events_statements_history; 
truncate table events_statements_summary_by_digest;
do sleep(60);
统计SQL的执行比例
select now(),(count_star/(select sum(count_star) FROM events_statements_summary_by_digest) * 100) as pct, count_star as sql_exec, left(digest_text,150) as stmt, digest from events_statements_summary_by_digest order by 2 desc;


关闭SQL的性能收集：
update setup_consumers set enabled='NO' where name IN ('events_statements_history','events_statements_current','statements_digest');