This website is under heavy load (queue full)

I just got this message today on my production site. Website is running an ROR backend with a React front end.

Current site is running on Hatchbox/Digital Ocean with 16vCPUs, 32gb Memory and 200gb SSD so its a big server.

Looking at the graphs on DO

• CPU doesn't go over 30%,
• Memory is at 15%
• The only thing that spiked was the Disk I/O that spiked to 1.17 mb/s

Any help would be appreciated.

Sounds like a lot of requests all came in at once. That's can happen when you're load testing, have a big spike in traffic (like launching something new) or if you're getting attacked by malicious users.

You can increase Passenger's queue size configuration, but it may just fill up the larger queue if Rails isn't processing requests fast enough. You might want to check and make sure that your response times in Rails are not slowing down with slow views / queries.

What's the best way to test slow queries?

Also thanks for the quick response Chris it's always appreciated :)

Skylight (my favorite), AppSignal, New Relic, etc are useful as they'll monitor your app's response times and can help you pinpoint slow stuff like queries or views.