慢SQL查询
搜索某个用户的 Top N 慢查询
### 排除 TiDB 内部的慢查询sql，并指定查找的用户名
select query_time, query, user
from information_schema.slow_query
where is_internal=false
and user="user1"
order by query_time desc
limit 2;
根据 SQL 指纹搜索同类慢查询:
1.先根据最近慢语句 List 查找特定慢语句:
select query_time, query, digest
from information_schema.slow_query
where is_internal = false
and time between '2025-03-01' and '2025-03-05'
order by query_time desc
limit 1 \G;
输出示例：
*************************** 1. row ***************************
query_time: 0.340376587
query: drop table dep;
digest: e63277c19304d71f13b9f5b47e636923b76faa096f6c79f5abd5ae4ae9917176
1 row in set (0.01 sec)
2.再根据 digest 确定同类慢查询:
select query, query_time
from information_schema.slow_query
where digest ="e63277c19304d71f13b9f5b47e636923b76faa096f6c79f5abd5ae4ae9917176" \G;
输出示例：
*************************** 1. row ***************************
query: drop table dep;
query_time: 0.340376587
1 row in set (0.03 sec)
3.搜索统计信息为 pseudo 的慢查询 SQL 语句:
select query, query_time, stats
from information_schema.slow_query
where is_internal = false
and stats like '%pseudo%'\G;
输出示例：
*************************** 1. row ***************************
query: SELECT count(*) FROM (SELECT c.c_id, c.c_d_id, c.c_balance c1, c_ytd_payment, (SELECT sum(ol_amount) FROM orders, order_line WHERE OL_W_ID=O_W_ID AND OL_D_ID = O_D_ID AND OL_O_ID = O_ID AND OL_DELIVERY_D IS NOT NULL AND O_W_ID=? AND O_D_ID=c.C_D_ID AND O_C_ID=c.C_ID) sm FROM customer c WHERE c.c_w_id = ?) t1 WHERE c1+c_ytd_payment <> sm [arguments: (1, 1)];
query_time: 0.728453657
stats: orders:pseudo,order_line:pseudo,customer:pseudo