20160111-(优化日记)

1.查询sql:SELECT IFNULL(SUM(acctsessiontime),0) sumacct FROM radacct a WHERE a.username= '15054693897' AND a.acctstoptime IS NOT NULL
2.无索引
(1)执行计划

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	a	range	ind_acctst	ind_acctst	6	(NULL)	1434442	Using index condition; Using where

(2)sql执行时间

state	duration (summed) in sec	percentage
Sending data	6.42342	99.97930

(3)总耗时      : 7.038 sec
3.创建索引
(1) ALTER TABLE `qwifi`.`radacct`   
  ADD  INDEX `index_usr_stoptime` (`username`, `acctstoptime`);
(2)执行计划

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	a	range	ind_acctst	ind_acctst	200	(NULL)	64	Using index condition

(3)总耗时      : 0.092 sec