唔想每個server 行一次 ssh 再run command，寫個script 同做一次所有servers 既時間差。不過下次再run 就可以慳好多時間。IaC / automation always win. Ansible playbook 可能都有，可惜冇機會用到Ansible 。 放左去gist。有用既請拍下 likecoin ，Thanks：）
公司最近有個deployment，要run個SQL patch。係QA 同staging 都冇事，點知一去production run左30mins 都未行完，terminated & rollback. 原來係其中一個update statement 行subquery，where id = (select …) mysql 會run select on each row 🙁 DataSet 一大，慢到嘔。
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CREATE TABLE alarm_backup SELECT * FROM alarm; UPDATE alarm a SET a.status = 'active' , ....... WHERE a.id = ( SELECT al.id FROM alarm_backup ab JOIN device d ON ab.device_id = d.id JOIN ...... WHERE ..... ); |
其實subquery 係唔需要⋯⋯
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CREATE TABLE alarm_backup SELECT * FROM alarm; UPDATE alarm a JOIN device d ON a.device_id = d.id JOIN ...... SET a.status = 'active' , ....... WHERE ..... ； |
故事教訓我地： 1) 放假返黎之後小心點，你唔係到個時既Peer review 都要睇返。 2) 唔好咁容易信你上司，上左神枱技術係會回塘 😂
funny, you can get a free tee shirt when you make 5 pull request in Oct 1-31. This is the 5th year but I only knew it now 😛 check out the details in https://hacktoberfest.digitalocean.com/