2018/06/22

This isn't the first time this has happened... outgoing toots are being delayed by something like 1.5-2 hours. Last time, we upped the number of threads from 15 to 25 (according to my memory; apparently we didn't document it), and that seemed to fix the blockage.

So this time, I'm making notes.

Editing /etc/systemd/system/mastodon-sidekiq.service:

• changing DB_POOL=5 to DB_POOL=20
• changing sidekiq -c 25 to sidekiq -c 40

...and rebooted (which wasn't strictly necessary, but the system was asking for one because of a kernel upgrade some days ago).

...and then it turned out I had forgotten to save my changes before rebooting, so I had to do this:

root@tootcat2:~# systemctl restart mastodon-sidekiq.service
Warning: mastodon-sidekiq.service changed on disk. Run 'systemctl daemon-reload' to reload units.
root@tootcat2:~# systemctl daemon-reload

After finding this explanation, I understood two things:

• DB_POOL should be the same as the sidekiq -c value
• I actually have plenty of CPU headroom, and can boost this quite a bit more.

I first tried 40, and that helped a bit -- but the "busy" queue was still getting stuck around 3500.

So then I bumped it up to 100, and within a minute or two the queue was down under 100.

Also, do things in this order:

root@tootcat2:~# systemctl daemon-reload
root@tootcat2:~# systemctl restart mastodon-sidekiq.service