MySQL数据库优化思想与优化实战（一）
网站打开慢排查基本思想
多次执行，查看慢查询
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SHOW VARIABLES like '%pro%'
查看字段条件列的唯一性
SELECT COUNT(DISTINCT id) FROM nr_order
SELECT ADDTIME from nr_order limit 5多次执行，查看慢查询
show full processlist
SHOW VARIABLES like '%pro%'
SELECT COUNT(DISTINCT id) FROM nr_order
SELECT ADDTIME from nr_order limit 5