生产环境高并发MySQL SQL语句优化案例
生产环境高并发MySQLSQL语句优化10条案例声明：本案例为老男孩linux运维实战培训的数据库优化教学案例，如有转载务必保留本版权声明在实际工作中，运维或DBA人员
?,'?,'?,'绉︽矝','寰愬厠');
最终解决方案：有用到boy_title_upper的索引，慢的原因再观察
案例4：分析归类后的慢查询日志如下。
______________________________________________________________________ 004 ___
Count: 378(6.04%)
Time: 2604 s total, 6.888889 s avg, 3 s to 65 s max(7.63%)
95% of Time : 2031 s total, 5.657382 s avg, 3 s to 17 s max
Lock Time (s) : 0 total, 0 avg, 0 to 0 max(0.00%)
95% of Lock : 0 total, 0 avg, 0 to 0 max
Rows sent: 5 avg, 0 to 10 max(3.24%)
Rows examined : 2.81k avg, 92 to 24.91k max(27.61%)
Database: docresource
Users:
ett_oldboy@ 10.0.1.28 : 100.00% (378) of query, 100.00% (6256) of all users
Query abstract:
SELECT h.boy_id ,MAX(h.boy_his_edit_time) AS boy_his_edit_time FROM t_boy_his h WHERE h.boy_his_isteammate=N AND h.boy_his_state=N AND h.boy_his_editor_user_id_encrypt='S' GROUP BY h.boy_id ORDER BY h.boy_his_edit_time DESC LIMIT N,N;
Query sample:
selecth.boy_id ,max(h.boy_his_edit_time) from t_boy_his hwhere h.boy_his_editor_user_id_encrypt='pGVpWQVlYdglTaQ0Z' and h.boy_his_isteammate=1 and h.boy_his_state=1 group by h.boy_id order by h.boy_his_edit_time desc limit 0,4;
最终解决方案：
alter table t_boy_his add index editor_user_iden_docid(boy_his_editor_user_id_encrypt, boy_id);
1,sql改成：SELECT h.boy_id ,MAX(h.boy_his_edit_time) AS boy_his_edit_time FROM t_boy_his h WHERE h.boy_his_isteammate='pGVpWQVlYdglTaQ0Z' AND h.boy_his_state=1 AND h.boy_his_editor_user_id_encrypt='S' GROUP BY h.boy_id ORDER BY null
2，再在程序里，用java对boy_his_edit_time排序。
案例5：分析归类后的慢查询日志如下。
______________________________________________________________________ 005 ___
Count: 211(3.37%)
Time: 1218 s total, 5.772512 s avg, 3 s to 30 s max(3.57%)
95% of Time : 1022 s total, 5.11 s avg, 3 s to 13 s max
Lock Time (s) : 0 total, 0 avg, 0 to 0 max(0.00%)
95% of Lock : 0 total, 0 avg, 0 to 0 max
Rows sent: 2 avg, 0 to 2 max(0.72%)
Rows examined : 3.61k avg, 110 to 19.59k max(19.81%)
Database:
Users:
ett_oldboy@ 10.0.1.28 : 100.00% (211) of query, 100.00% (6256) of all users
Query abstract:
SELECT h.boy_id ,MAX(h.boy_his_edit_time) AS boy_his_edit_time FROM t_boy_his h WHERE h.boy_his_isteammate=N AND h.boy_his_state=N AND h.boy_his_editor_user_id=N GROUP BY h.boy_id ORDER BY h.boy_his_edit_time DESC LIMIT N,N;
Query sample:
selecth.boy_id ,max(h.boy_his_edit_time) as boy_his_edit_time from t_boy_his hwhere h.boy_his_isteammate=1 and h.boy_his_state=1 and h.boy_his_editor_user_id=300000178518 group by h.boy_id order by h.boy_his_edit_time desc limit 0,2;
最终解决方案：此sql由查前面一个sql代替，删除。
案例6：分析归类后的慢查询日志如下。
______________________________________________________________________ 006 ___
Count: 30(0.48%)
Time: 940 s total, 31.333333 s avg, 3 s to 77 s max(2.76%)
95% of Time : 790 s total, 28.214286 s avg, 3 s to 69 s max
Lock Time (s) : 0 total, 0 avg, 0 to 0 max(0.00%)
95% of Lock : 0 total, 0 avg, 0 to 0 max
Rows sent: 1 avg, 1 to 1 max(0.05%)
Rows examined : 10.96k avg, 1.82k to 28.12k max(8.56%)
Database: docresource
Users:
ett_oldboy@ 10.0.1.28 : 100.00% (30) of query, 100.00% (6256) of all users
Query abstract: