Debian 13, Postgres, and the US/* time zones

source: https://rachelbythebay.com/w/2025/09/11/debtz/
comments: news.ycombinator.com/item?id=45218111

If you're running Debian 12 and Postgres, you're in or around the Americas, and you're planning on upgrading to Debian 13, you might hit a fun little snag. I did when I did my first (testing) box:

2025-08-29 06:28:12.038 GMT [220328] LOG:  invalid value for parameter "log_timezone": "US/Pacific"
2025-08-29 06:28:12.038 GMT [220328] LOG:  invalid value for parameter "TimeZone": "US/Pacific"
2025-08-29 06:28:12.038 GMT [220328] FATAL:  configuration file "/etc/postgresql/15/main/postgresql.conf" contains errors

At the time, I went "WTF?" and just commented it out to get it running again. I had bigger fish to fry... and just kind of forgot about it. Everything seemed fine.

Here it is two weeks later and I just realized that one of my little history viewing tools for my temperature tracking stuff is generating graphs that run from 5 PM to 4 PM. In other words, it's showing me a UTC-based day, not a US/Pacific (PDT at the moment) day. 5 PM here during the summer is midnight UTC.

It took far too long to realize what was going on here. So I went, okay, uh, US/Los_Angeles? No. It's now America/Los_Angeles.

The worst part about this is that it didn't get so much as a mention in the Debian 13 release notes. I read through that document before going for it and never encountered it. Indeed, even now, you won't find "tzdata" or "zone" in it.

Normally when weird stuff like this happens, someone who lives on the bleeding edge runs into it and reports it. That's what happened with the xz kerfuffle: some person running the latest stuff hit some anomalous readings and went digging. Here, too, a few people hit the problem well before I did.

They hit it in 2023. US/* was moved to tzdata-legacy, and a few people asked for something that would pop up during upgrades. I guess it didn't happen.

So, as a public service, here you go. This is your notification.