The manual is still quite comprehensive, but their doc updates seemingly went off the rails during the switch to quarterly "Innovation" releases starting with MySQL 8.1, and never really recovered. They keep forgetting to update various pages at release time, for example the keywords reference or error code reference. Or sometimes omitting major changes from the release notes (which now appear to be AI generated), and then they update it retroactively, days or weeks after the release.

I used to submit doc bugs for these as I found them, and I must say the documentation team has always been very responsive and fast at fixing them, even quite recently. But I've mostly stopped submitting new doc bugs, as I can't keep spending unpaid time on this every quarter, it just isn't sustainable. They really need to have a better internal process or checklist for quarterly release doc updates.

Combined with their "closed" development process and no-longer-public worklogs (nothing under development is visible at all until the release), it becomes impossible to predict what is going to change in the next release, or what has already changed in the most recent release.

MariaDB is a lot better about everything being open/public, but they also tend to have similar delays on doc updates, occasional missing release notes items, etc. It's really strange. I mean, writing docs isn't fun, but why spend time developing a feature but then fail to mention it anywhere?