Comment by wbl
6 hours ago
Yeah but you don't need to worry about your data existing. MySQL has been known to silently fail the one job of a DB.
6 hours ago
Yeah but you don't need to worry about your data existing. MySQL has been known to silently fail the one job of a DB.
Not in around 15 years. You're thinking of when MyISAM was the default storage engine for MySQL. It has been InnoDB for over a decade. InnoDB is very reliable - I've never had a single data loss incident in all that time, and I've managed some very large (PB-scale) and active databases.
Postgres is definitely more difficult to administer.
I recall this being the case A LOOOONG time ago but I haven't heard of, read about, been warned to look out for or personally seen such a thing in forever. Have you?
* I'm running a lot of MySQL stuff and such a topic might be of interest to me
From what I can tell, MySQL is supposed to be safe since 2018 if you have no data from before 2010.
The fact that you still can't use DDL in transactions makes life exceedingly painful, but it's technically safe if you write your migration code carefully enough.
Some places still have columns declared as utf8 instead of utf8mb4, and there's a special place in hell for authors of the MySQL general clusterfuck regarding encodings - it was all nice and great if you didn't care about anything other than latin1 or ASCII - go outside that before utf8 option and it was horror that even experienced operators managed to fuckup (I have a badge from a Google conference in 2017 with nicely visible effect of "we have mixed up one of the three separate encoding settings in MySQL and now you have mojibake in your badge").
And then there's UTF8 not actually being UTF8, which can result in total lockup of a table if someone inputs a character that does not fit in UCS-2 and now you need to recover the database from backup and preferably convert all instances of utf8 to utf8mb4, because fuck you that's why.
Lack of transactional DDL is certainly painful, but not unique for MySQL. Oracle doesn't support it either.
Yes, it is messy when you want your MySQL databases to be mission critical in production, e.g. handling a large amount of customer data. Historically MySQL's High Availability architecture has a lot of design and implementation issues because it was an afterthought. Dealing with large amount of critical data means you need it to be performant, reliable and available at the same time, which is hard and requires you to deal with caching, sharding, replication, network issues, zone/resource planning, failovers, leader elections and semi-sync bugs, corrupted logs, manually fixing bad queries that killed the database, data migration, version upgrades, etc. There is a reason why big corps like Google/Meta has dedicated teams of experts (like people who actually wrote the HA features) to maintain their mission critical MySQL deployments.