Ask Lemmy

27241 readers

3741 users here now

A Fediverse community for open-ended, thought provoking questions

Rules: (interactive)

1) Be nice and; have fun

Doxxing, trolling, sealioning, racism, and toxicity are not welcomed in AskLemmy. Remember what your mother said: if you can't say something nice, don't say anything at all. In addition, the site-wide Lemmy.world terms of service also apply here. Please familiarize yourself with them

2) All posts must end with a '?'

This is sort of like Jeopardy. Please phrase all post titles in the form of a proper question ending with ?

3) No spam

Please do not flood the community with nonsense. Actual suspected spammers will be banned on site. No astroturfing.

4) NSFW is okay, within reason

Just remember to tag posts with either a content warning or a [NSFW] tag. Overtly sexual posts are not allowed, please direct them to either [email protected] or [email protected]. NSFW comments should be restricted to posts tagged [NSFW].

5) This is not a support community.

It is not a place for 'how do I?', type questions. If you have any questions regarding the site itself or would like to report a community, please direct them to Lemmy.world Support or email [email protected]. For other questions check our partnered communities list, or use the search function.

6) No US Politics.

Please don't post about current US Politics. If you need to do this, try [email protected] or [email protected]

Reminder: The terms of service apply here too.

Partnered Communities:

Logo design credit goes to: tubbadu

founded 2 years ago

MODERATORS

174

What's the worst way you ever broke production? (lemm.ee)

submitted 10 months ago by [email protected] to c/asklemmy

104 comments fedilink hide all child comments

Fess up. You know it was you.

you are viewing a single comment's thread
view the rest of the comments

[–] Clent 19 points 10 months ago (1 children)

UPDATE ON articles SET status = 0 WHERE body LIKE '%...%'

On master production server, running myisam, against a text column, millions of rows.

This causes queries to stack because table locks

Rather than waiting for the query to finish. a slave was promoted to master.

Lesson: don't trust mysqladmin to not do something bad.

[–] EmasXP 2 points 10 months ago

Table locks can be a real pain. You know you need to do the change, but the system is constantly running queries towards it. Now days it's a bit easier with algorithm=inplace and lock=none, but in the good old days you were on your own. Your only friend was luck. Large migrations like that still gives me shivers