今天給一個客戶巡檢的情況下發從庫沒有業務的情況mysqld的cpu的一個core占用100%.查主庫慢查詢也沒有關于寫的SQL.
可以說是典的單進程復制把一個cpu占滿造成的．知道原因了，就好分析了．
分析一下binlog中寫的什么，看看有什么地方可以優化或是加速的．利用工具：pasrebinlog
利用show slave status/G; 查當前同步的到節點，然后對日值進行解析．
| git clone https://github.com/wubx/mysql-binlog-statistic.gitcd mysql-binlog-statistic/bin/parsebinlog /u1/mysql/logs/mysql-bin.000806...====================================Table xx_db.xxtable:Type DELETE opt： 101246Type INSERT opt： 103265================================... |
以最大的數排序看， 定位到: xx_db.xxtable，對于一個日值中能刪除10幾萬，寫入10幾萬．是不是這個表寫入比較慢了呢．
在從庫上查看innodb的相關情況：
| MySQL> show engine innodb status/G;...---TRANSACTION 1C0C2DFDF, ACTIVE 3 sec fetching rowsmysql tables in use 1, locked 13361 lock struct(s), heap size 407992, 477888 row lock(s), undo log entries 42MySQL thread id 43, OS thread handle 0x7fc1800c4700, query id 1908504 Reading event from the relay logTABLE LOCK table xx_db.xxtable trx id 1C0C2DFDF lock mode IXRECORD LOCKS space id 1002 page no 1975 n bits 1120 index `AK_movieid` of table xx_db.xxtable trx id 1C0C2DFDF lock_mode X locks rec but not gapRECORD LOCKS space id 1002 page no 6965 n bits 264 index `GEN_CLUST_INDEX` of table xx_db.xxtable trx id 1C0C2DFDF lock_mode X locks rec but not gapRECORD LOCKS space id 1002 page no 6967 n bits 256 index `GEN_CLUST_INDEX` of table xx_db.xxtable trx id 1C0C2DFDF lock_mode X locks rec but not gapRECORD LOCKS space id 1002 page no 6973 n bits 264 index `GEN_CLUST_INDEX` of table xx_db.xxtable trx id 1C0C2DFDF lock_mode X locks rec but not gapRECORD LOCKS space id 1002 page no 6982 n bits 256 index `GEN_CLUST_INDEX` of table xx_db.xxtable trx id 1C0C2DFDF lock_mode X locks rec but not gapRECORD LOCKS space id 1002 page no 6983 n bits 256 index `GEN_CLUST_INDEX` of table xx_db.xxtable trx id 1C0C2DFDF lock_mode X locks rec but not gapRECORD LOCKS space id 1002 page no 6987 n bits 256 index `GEN_CLUST_INDEX` of table xx_db.xxtable trx id 1C0C2DFDF lock_mode X locks rec but not gapRECORD LOCKS space id 1002 page no 6999 n bits 256 index `GEN_CLUST_INDEX` of table xx_db.xxtable trx id 1C0C2DFDF lock_mode X locks rec but not gapRECORD LOCKS space id 1002 page no 7000 n bits 256 index `GEN_CLUST_INDEX` of table xx_db.xxtable trx id 1C0C2DFDF lock_mode X locks rec but not gapTOO MANY LOCKS PRINTED FOR THIS TRX: SUPPRESSING FURTHER PRINTS----------------------------END OF INNODB MONITOR OUTPUT... |
從Innodb 的monitor output 中也可看到 xx_db.xxtable 這表已經是表級表了，造成并發比較低，而且有大量的： GEN_CLUST_INDEX 而且屬于一個事務． GEN_CLUST_INDEX表示沒有主建，內部產生一個主建，對于內部產生的主建很很容易造成page拆分的操作．
新聞熱點
疑難解答
