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Comment by boxed

9 hours ago

Seconded. Coming from MySQL this is a huge regression that makes Postgres look like something from the 80s. I still wonder why this isn't seen as the absolutely highest priority.

I have not ran MySQL for some years but it at least used to have exactly the same issue. Upgrading a database with MySQL can take a long time if you have many tables. The main difference is only really that PostgreSQL does it with a separate tool, pg_upgrade, while MySQL does it as part of the main binary.

For both MySQL and PostgreSQL you will need to use some kind of logical upgrades if you want no downtime.

  • MySQL has advocated for decades spinning up a replica with the upgraded version, waiting for it to catch up to master before promoting it to the new master. You can do the same thing with Postgres.

    • Exactly, MySQL and PostgreSQL are the same here. Maybe one is a bit faster than the other at doing major version upgrades but the behaviours are quite similar.

Probably because it's an open source project and apparently none of its users cared about this feature enough to develop it or fund it.

  • It is also a bit tricky tradeoff. You do not want to be stuck with the same data format forever. So databases like MySQL and PostgreSQL need a downtime when doing a major version upgrade. They both try to keep it short, usually seconds, but minutes can happen in either database.