jordelver
Database connection errors running Oban on Heroku
This is probably my misunderstanding rather than an Ecto or Oban issue, but I’ve only seen this error since I deployed a toy app using Oban to Heroku.
I set the POOL_SIZE to 18 to allow for mix tasks and pgweb (my database client) to run.
I have one worker which hits a REST API and inserts about 1000 rows into a table within a transaction.
I haven’t seen the error when running on a schedule (I have a crontab entry setup in Oban) but when I insert a job via mix ( heroku run "POOL_SIZE=1 iex -S mix") I get this error.
15:12:47.956 [error] GenServer Oban.Queue.Default.Producer terminating
** (DBConnection.ConnectionError) connection not available and request was dropped from queue after 2655ms. This means requests are coming in and your connection pool cannot serve them fast enough. You can address this by:
1. By tracking down slow queries and making sure they are running fast enough
2. Increasing the pool_size (albeit it increases resource consumption)
3. Allow requests to wait longer by increasing :queue_target and :queue_interval
See DBConnection.start_link/2 for more information
(db_connection) lib/db_connection.ex:745: DBConnection.run/3
(stdlib) gen_server.erl:637: :gen_server.try_dispatch/4
(stdlib) gen_server.erl:711: :gen_server.handle_msg/6
(stdlib) proc_lib.erl:249: :proc_lib.init_p_do_apply/3
-
I’m pretty sure that Oban uses the same Repo and database connection pool as you tell Oban what your Repo is called in the config. Is that correct?
-
I believe that each Oban worker is run in its own isolated process but I’m guessing it still shares database connections from the pool?
-
Should I be worried about this?
Thanks for any insight!
Most Liked
sorentwo
Your initial issue was likely due to the single connection being held by your job while oban tries to fetch more jobs or record heartbeats.
That’s correct. Oban uses one additional connection for pubsub notifications.
I typically use something like this in application.ex to prevent jobs running in an iex session:
defp oban_config do
opts = Application.get_env(:my_app, Oban)
if Code.ensure_loaded?(IEx) and IEx.started?() do
opts
|> Keyword.put(:crontab, false)
|> Keyword.put(:queues, false)
else
opts
end
end
benwilson512
I’m not 100% sure about how it works with heroku, but if they let you run commands inside a running dyno, then if you use releases you can just attach a console to that release allowing you to use the pool that it is already running instead of spawning an additional instance of the app.
If you can’t do a release + remote_console on heroku, then is there an issue just opening up another 20 connections? Will it reach a database limit? You probably want to make sure that you have a flag to disable Oban on the iex -S mix session by the way, since you probably don’t want to run jobs inside that session.
axelson
I also run on Heroku and I’ve noticed that sometimes ecto goes over the number of connections allotted to it so I leave more of a buffer than you are leaving here. I’d probably set the POOL_SIZE to 15.
Popular in Questions
Other popular topics
Latest Oban Threads
Latest on Elixir Forum
Sponsor Spotlight
Catch errors, track performance, monitor hosts and more.
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #deployment
- #library
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #channels
- #elixirconf
- #exunit
- #discussion
- #code-sync
- #javascript
- #podcasts
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixir-ls
- #phoenix_html
- #iex
- #blog-post
- #graphql
- #genstage
- #ai
- #websockets
- #supervisor
- #advent-of-code
- #elixirconf-us
- #distillery
- #processes
- #forms
- #api
- #metaprogramming
- #security
- #performance
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Real-time error tracking, performance insights, and observability for devs.
Develop your skills with books, videos, and courses.
Enabling companies to succeed by building software people love.
The deployment platform built for Elixir: PaaS ease, VPS control.
Courses that'll move you from confusion to "Aha, now I get it!"