MySQL 8.0 Query Rewrite支持DML

MySQL 8.0 Query Rewrite支持SELECT INSERT UPDETE DELETE REPLACE语句重写

这个功能要点赞，比如开发上线时，有个SQL查询字段索引忘记加了，直接把线上CPU打满，此时，你可以将SQL重写，让业务先报错，别打死数据库，然后马上通知开发回滚，等加完索引后再上线。

安装插件

mysql -S /tmp/mysql_hcy.sock -p123456 <./install_rewriter.sql

查看是否生效

SHOW GLOBAL VARIABLES LIKE 'rewriter_enabled';

编写重写规则

insert into query_rewrite.rewrite_rules(pattern, replacement, pattern_database) values ("SELECT * from sbtest1 limit ?","SELECT k,c from sbtest1 limit ?","test");

意思为：

将以下语句

SELECT * from sbtest1 limit ?;

改写成：

SELECT k,c from sbtest1 limit ?;

注：问号?为变量

执行规则生效

CALL query_rewrite.flush_rewrite_rules();

演示

mysql> SELECT * from sbtest1 limit 1\G;*************************** 1. row ***************************k: 499284c: 83868641912-28773972837-60736120486-75162659906-27563526494-20381887404-41576422241-93426793964-56405065102-335184323301 row in set, 1 warning (0.00 sec) ERROR: No query specified mysql> show warnings\G*************************** 1. row ***************************  Level: Note   Code: 1105Message: Query 'SELECT * from sbtest1 limit 1' rewritten to 'SELECT k,c from sbtest1 limit 1' by a query rewrite plugin1 row in set (0.00 sec)