this post was submitted on 04 Aug 2023
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This new version introduced a system so that your instance stops sending out content to other instances that are supposedly dead / offline.

Unfortunately for some reason there's false positives. When I checked comparing the results from a curl request vs the information in our Lemmy database I found over 350+ false positives.

In the DB there is a table called "instance" which has a column called "updated". If the date on that column is older than 3 days, your server will stop sending any content to those instances.

For some reason I had entries that were dated as last being alive in July, while actually they were always up. If an entry is incorrect, you can fix it by manually using an update statement and adding today's date. If your instance is not too large you can safely update all entries to today's date and check if everything works as expected from then on any new content created on your instances.

The dead instances won't have an impact unless your instance is larger and generates more content, thus it might be easier to simply update all entries and have Lemmy believe they're all alive if you start noticing wonky behavior and don't want to check one by one.

If you don't know how to access the database run this command where domaincom is your instance domain without the dot.

  1. docker exec -it domaincom_postgres_1 busybox /bin/sh

  2. psql -U

(The default user is 'lemmy') You could technically do this is one single step, but it's good to know the command to get shell access to the container itself if you didn't know how to.

This should give you access to a postgres CLI interface. Use \c to connect, \dt to list tables and \d+ tablename to list table definition. You can also run SQL queries from there.

Try with this query: SELECT * from instance to list all instances and their updated date.

You can use other SQL queries to get better results or correct false positives. Just be careful with what you execute since there's no undo.

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[–] nix@merv.news 5 points 1 year ago (2 children)

Very useful thanks for sharing! We should have an admin tips community to collect information like this

https://wiki.lemmyadmin.site

You can post it here and the explanation why it happens.