mysql慢查詢導(dǎo)致的CPU打滿

異常現(xiàn)象

大量的慢SQL導(dǎo)致8核CPU全部打滿，解決前后CPU如圖


image.png

實(shí)例基礎(chǔ)信息：

  • 數(shù)據(jù)庫版本：MariaDB10.0.27
  • 硬件信息：8核cpu+16G內(nèi)存+500GSSD
  • 數(shù)據(jù)庫中數(shù)據(jù)量> innodb buffer pool配置
  • 表結(jié)構(gòu)
CREATE TABLE `tablename` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主鍵',
  `gid` varchar(36) NOT NULL COMMENT '全局標(biāo)識(shí)',
  `create_time` int(11) NOT NULL COMMENT '創(chuàng)建時(shí)間',
  `update_time` int(11) NOT NULL COMMENT '更新時(shí)間',
  `biz_type` varchar(16) DEFAULT NULL COMMENT '業(yè)務(wù)號(hào)',
  `biz_chnl` int(11) NOT NULL DEFAULT '-1' COMMENT '業(yè)務(wù)渠道編號(hào)',
  `user_gid` char(36) NOT NULL COMMENT '用戶全局唯一標(biāo)識(shí)',
  `trans_gid` char(36) NOT NULL COMMENT '交易唯一標(biāo)識(shí),消息類型與gid關(guān)系為：0：額度變更記錄gid, 1:借款gid, 2:還款gid',
  `msg_type` int(11) NOT NULL COMMENT '消息類型：0：用戶額度變更，1：借款狀態(tài)變更，2：還款狀態(tài)變更',
  `msg_status` int(11) NOT NULL COMMENT '消息狀態(tài)：0：處理中，1：處理成功，2：處理失敗',
  `msg_content` varchar(4096) NOT NULL COMMENT '消息內(nèi)容JSON格式',
  `return_code` varchar(16) DEFAULT NULL COMMENT '返回狀態(tài)碼',
  `return_desc` varchar(4000) DEFAULT NULL COMMENT '狀態(tài)描述',
  `trans_return_code` varchar(16) DEFAULT NULL COMMENT '交易狀態(tài)碼',
  `trans_return_desc` varchar(255) DEFAULT NULL COMMENT '交易結(jié)果描述',
  `retry_next_time` int(11) NOT NULL DEFAULT '0' COMMENT '下次重試時(shí)間',
  `retry_num` int(11) NOT NULL DEFAULT '0' COMMENT '重試次數(shù)',
  `status` int(11) NOT NULL DEFAULT '0' COMMENT '發(fā)送狀態(tài)：0 準(zhǔn)備就緒，1 發(fā)送成功， 2 發(fā)送失敗，3 結(jié)果未知',
  `is_valid` bit(1) NOT NULL DEFAULT b'1' COMMENT '是否有效',
  PRIMARY KEY (`id`),
  UNIQUE KEY `idx_gid` (`gid`),
  KEY `idx_create_time` (`create_time`),
  KEY `idx_update_time` (`update_time`),
  KEY `idx_status` (`status`),
  KEY `idx_bizt_chnl` (`biz_type`,`biz_chnl`),
  KEY `idx_return_trans_code` (`return_code`,`trans_return_code`),
  KEY `idx_trans_gid` (`trans_gid`) USING BTREE,
  KEY `idx_user_gid` (`user_gid`)
) ENGINE=InnoDB AUTO_INCREMENT=9630777 DEFAULT CHARSET=utf8 COMMENT='x x x x'
  • 表數(shù)據(jù)量
MariaDB [sailfish]> select count(*) from tablename;
+----------+
| count(*) |
+----------+
|  9630917 |
+----------+

修改SQL

-開發(fā)原始SQL

MariaDB [sailfish]> SELECT id, gid,create_time,update_time,biz_type,biz_chnl,user_gid,trans_gid,msg_type,msg_status,msg_content,return_code,return_desc,trans_return_code,trans_return_desc,retry_next_time,retry_num,status,is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511333699 ) order by id limit 500;
Empty set (15.40 sec)   
MariaDB [sailfish]> explain SELECT id, gid,create_time,update_time,biz_type,biz_chnl,user_gid,trans_gid,msg_type,msg_status,msg_content,return_code,return_desc,trans_return_code,trans_return_desc,retry_next_time,retry_num,status,is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511333699 ) order by id limit 500;
+------+-------------+--------------------+-------+--------------------------+---------+---------+------+------+-------------+
| id   | select_type | table              | type  | possible_keys            | key     | key_len | ref  | rows | Extra       |
+------+-------------+--------------------+-------+--------------------------+---------+---------+------+------+-------------+
|    1 | SIMPLE      | tablename | index | idx_status,idx_bizt_chnl | PRIMARY | 4       | NULL | 6578 | Using where |
+------+-------------+--------------------+-------+--------------------------+---------+---------+------+------+-------------+

-修改SQL去掉limit 500

MariaDB [sailfish]> SELECT id, gid,create_time,update_time,biz_type,biz_chnl,user_gid,trans_gid,msg_type,msg_status,msg_content,return_code,return_desc,trans_return_code,trans_return_desc,retry_next_time,retry_num,status,is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511333699 ) order by id;
Empty set (1.86 sec) 
MariaDB [sailfish]> explain SELECT id, gid,create_time,update_time,biz_type,biz_chnl,user_gid,trans_gid,msg_type,msg_status,msg_content,return_code,return_desc,trans_return_code,trans_return_desc,retry_next_time,retry_num,status,is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511333699 ) order by id;
+------+-------------+--------------------+------+--------------------------+---------------+---------+-------+--------+----------------------------------------------------+
| id   | select_type | table              | type | possible_keys            | key           | key_len | ref   | rows   | Extra                                              |
+------+-------------+--------------------+------+--------------------------+---------------+---------+-------+--------+----------------------------------------------------+
|    1 | SIMPLE      | tablename | ref  | idx_status,idx_bizt_chnl | idx_bizt_chnl | 51      | const | 708040 | Using index condition; Using where; Using filesort |
+------+-------------+--------------------+------+--------------------------+---------------+---------+-------+--------+----------------------------------------------------+
  • 修改SQL去掉order by limit 500（第一次解決方案，剛開始有效果，一周后查詢時(shí)間又逐漸增長，cpu又打滿，和之前一樣）
MariaDB [sailfish]> SELECT id, gid,create_time,update_time,biz_type,biz_chnl,user_gid,trans_gid,msg_type,msg_status,msg_content,return_code,return_desc,trans_return_code,trans_return_desc,retry_next_time,retry_num,status,is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511333699 );
Empty set (2.18 sec)

MariaDB [sailfish]> explain SELECT id, gid,create_time,update_time,biz_type,biz_chnl,user_gid,trans_gid,msg_type,msg_status,msg_content,return_code,return_desc,trans_return_code,trans_return_desc,retry_next_time,retry_num,status,is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511333699 );
+------+-------------+--------------------+------+--------------------------+---------------+---------+-------+--------+------------------------------------+
| id   | select_type | table              | type | possible_keys            | key           | key_len | ref   | rows   | Extra                              |
+------+-------------+--------------------+------+--------------------------+---------------+---------+-------+--------+------------------------------------+
|    1 | SIMPLE      | tablename | ref  | idx_status,idx_bizt_chnl | idx_bizt_chnl | 51      | const | 708040 | Using index condition; Using where |
+------+-------------+--------------------+------+--------------------------+---------------+---------+-------+--------+------------------------------------+

索引更改

  • 根據(jù)where條件增加組合索引前
MariaDB [test]> SELECT id, gid, create_time, update_time, biz_type, biz_chnl, user_gid, trans_gid, msg_type, msg_status, msg_content, return_code, return_desc, trans_return_code, trans_return_desc, retry_next_time, retry_num, status, is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511483534 );
Empty set (13.34 sec)

MariaDB [test]> explain SELECT id, gid, create_time, update_time, biz_type, biz_chnl, user_gid, trans_gid, msg_type, msg_status, msg_content, return_code, return_desc, trans_return_code, trans_return_desc, retry_next_time, retry_num, status, is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511483534 );
+------+-------------+--------------------+------+----------------------------------------------+---------------+---------+-------+--------+------------------------------------+
| id   | select_type | table              | type | possible_keys                                | key           | key_len | ref   | rows   | Extra                              |
+------+-------------+--------------------+------+----------------------------------------------+---------------+---------+-------+--------+------------------------------------+
|    1 | SIMPLE      | tablename | ref  | idx_status,idx_bizt_chnl,idx_retry_next_time | idx_bizt_chnl | 51      | const | 770126 | Using index condition; Using where |
+------+-------------+--------------------+------+----------------------------------------------+---------------+---------+-------+--------+------------------------------------+
1 row in set (0.06 sec)
  • 根據(jù)where條件增加組合索引后
pt-online-schema-change -uroot -pxxxxxx --charset=utf8 --alter="add index idx_multi(`status`,`biz_type`)" --dry-run --nocheck-replication-filters --recursion-method=none --print D=sailfish,t= tablename 

MariaDB [test]> SELECT id, gid, create_time, update_time, biz_type, biz_chnl, user_gid, trans_gid, msg_type, msg_status, msg_content, return_code, return_desc, trans_return_code, trans_return_desc, retry_next_time, retry_num, status, is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511483534 );
Empty set (0.06 sec)

MariaDB [test]> explain SELECT id, gid, create_time, update_time, biz_type, biz_chnl, user_gid, trans_gid, msg_type, msg_status, msg_content, return_code, return_desc, trans_return_code, trans_return_desc, retry_next_time, retry_num, status, is_valid FROM tablename WHERE ( status = 2 AND biz_type = 'swqian' AND retry_next_time < 1511483534 );
+------+-------------+--------------------+------+--------------------------------------------------------+-----------+---------+-------------+------+------------------------------------+
| id   | select_type | table              | type | possible_keys                                          | key       | key_len | ref         | rows | Extra                              |
+------+-------------+--------------------+------+--------------------------------------------------------+-----------+---------+-------------+------+------------------------------------+
|    1 | SIMPLE      | tablename | ref  | idx_status,idx_bizt_chnl,idx_retry_next_time,idx_multi | idx_multi | 55      | const,const |    1 | Using index condition; Using where |
+------+-------------+--------------------+------+--------------------------------------------------------+-----------+---------+-------------+------+------------------------------------+
1 row in set (0.01 sec)

增加索引時(shí)遇到的問題

  • 使用pt-online-schema-change更改表結(jié)構(gòu)時(shí)，因?yàn)楫?dāng)時(shí)有40多條慢查詢跑著，pt-online-schema-change被阻塞，等待2分鐘效果很差，中建表只有幾百條數(shù)據(jù)，停止pt-online-schema-change并刪除中間表、觸發(fā)器
  • 與開發(fā)溝通這40多條慢SQL可以臨時(shí)注釋，結(jié)合開發(fā)、運(yùn)維注釋掉該功能
  • 使用pt-online-schema-change更改表結(jié)構(gòu)，用時(shí)10分鐘，重新恢復(fù)業(yè)務(wù)，cpu趨于穩(wěn)定，如第一張圖

定位問題使用的工具

  • pmm監(jiān)控慢SQL、用戶cpu、mysql user statics
  • mariadb server audit審計(jì)日志
  • elk顯示每秒慢SQL查詢量
  • linux：top
  • mysql 信息統(tǒng)計(jì)：select * from information_schema.processlist where command='query' order by time\G
最后編輯于 ：
?著作權(quán)歸作者所有,轉(zhuǎn)載或內(nèi)容合作請(qǐng)聯(lián)系作者
【社區(qū)內(nèi)容提示】社區(qū)部分內(nèi)容疑似由AI輔助生成，瀏覽時(shí)請(qǐng)結(jié)合常識(shí)與多方信息審慎甄別。
平臺(tái)聲明：文章內(nèi)容（如有圖片或視頻亦包括在內(nèi)）由作者上傳并發(fā)布，文章內(nèi)容僅代表作者本人觀點(diǎn)，簡(jiǎn)書系信息發(fā)布平臺(tái)，僅提供信息存儲(chǔ)服務(wù)。

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容