MySQL 8.0 Query Rewrite支持SELECT INSERT UPDETE DELETE REPLACE語句重寫
這個功能要點贊,比如開發上線時,有個SQL查詢字段索引忘記加了,直接把線上CPU打滿,此時,你可以將SQL重寫,讓業務先報錯,別打死數據庫,然後馬上通知開發回滾,等加完索引後再上線。
安裝插件
mysql -S /tmp/mysql_hcy.sock -p123456 <./install_rewriter.sql
查看是否生效
SHOW GLOBAL VARIABLES LIKE 'rewriter_enabled';
編寫重寫規則
insert into query_rewrite.rewrite_rules(pattern, replacement, pattern_database) values ( "SELECT * from sbtest1 limit ?", "SELECT k,c from sbtest1 limit ?", "test");
意思爲:
將以下語句
SELECT * from sbtest1 limit ?;
改寫成:
SELECT k,c from sbtest1 limit ?;
注:問號?爲變量
執行規則生效
CALL query_rewrite.flush_rewrite_rules();
演示
mysql> SELECT * from sbtest1 limit 1\G; *************************** 1. row *************************** k: 499284 c: 83868641912-28773972837-60736120486-75162659906-27563526494-20381887404-41576422241-93426793964-56405065102-33518432330 1 row in set, 1 warning (0.00 sec) ERROR: No query specified mysql> show warnings\G *************************** 1. row *************************** Level: Note Code: 1105 Message: Query 'SELECT * from sbtest1 limit 1' rewritten to 'SELECT k,c from sbtest1 limit 1' by a query rewrite plugin 1 row in set (0.00 sec)