[ahofmann]

MySQL is the PHP of databases. It was free, easy to setup and had the spotlight at the right time. The bad decisions that are baked into MySQL are plenty and really sad (like the botched utf8 defaults, the myisam storage engine, strange stuff around replication and mucu more)

[evanelias]

InnoDB became the default storage engine over 15 years ago. MyISAM is barely used by anyone today.

What "strange stuff around replication" are you referring to?

[ahofmann]

I don't have all the details anymore. But one of the non obvious things for me was that foreign key cascades where not in the binlogs. I also think that some changes in the database layout could lead to strange things on the replicas.

[booi]

It still blows my mind that they called that crappy partial buggy characterset “utf8”. Then later came out with actual utf8 and called it “utf8mb4”. Makes no sense

[evanelias]

They should have addressed it much earlier, but it makes way more sense in historical context: when MySQL added utf8 support in early 2003, the utf8 standard originally permitted up to 6 bytes per char at that time. This had excessive storage implications, and emoji weren't in widespread use at all at the time. 3 bytes were sufficient to store the majority of chars in use at that time, so that's what they went with.

And once they made that choice, there was no easy fix that was also backwards-compatible. MySQL avoids breaking binary data compatibility across upgrades: aside from a few special cases like fractional time support, an upgrade doesn't require rebuilding any of your tables.