knav_negi
We have three docker instances for our application and one MySQL database. We also have background jobs running in each instance which read from the database.
Having three instances mean, three background jobs reading from the database and if one job picks a row from the database, we want other jobs to skip it.
We tried to mitigate this issues with optimistic lock (using lock_version in ecto). we have a column as job_staus which is set once the job begins and if there is lock_version mismatch update would fail to indicate that some other job has already started for given row.
row
|> Ecto.Changeset.change(%{status: “job_started”})
|> Ecto.Changeset.optimistic_lock(:lock_version)
|> Repo.update!()
|> start_job()
|> update_status(%{status: “job_finished”})
rescue
Ecto.StaleEntryError ->
#job was started in another process.
:ignore
end
Is there any better way of handling this ?
Trending in Questions
I’m working on a project that simulates the bumbl example in the programming phoenix book. It acts almost like an email client. We have a...
New
Hello!
Could someone please give me a help/sample code, how to delete a file from s3 using waffle/waffle_ecto from Phoenix app.
I creat...
New
I’m seeing that a list inside a Kino.DataTable will be interpreted as a charlist, even if the Kino.configure() is set to charlists: :as_l...
New
So my question is quite simple and i have found no conclusive answer on forum, google or AI.
Should we use :erlang.float for Integer to ...
New
Hi, I’ve just set up an application with ash_authentication. There is only magic link strategy for now, so there is no confirmation add o...
New
Hello,
I know there is an approach for handling lists that allows for optimized traversal, but I can’t recall the specific method (somet...
New
If a change or preparation module uses Ash.Changeset.get_argument/2 or Ash.Query.get_argument/2 (or any of the other get_argument functio...
New
Other Trending Topics
I am happy to introduce the very α version of the new programming language compiled to BEAM.
Welcome Cure.
It has literally three kille...
New
Hi there! We created Gust: A task orchestrator inspired by Airflow.
For those who have never heard about Aiflow, it’s a Python-based wor...
New
Beam Bots (or just BB for short) is a framework for building fault-tolerant robotics applications in Elixir using familiar OTP patterns. ...
New
Xamal is a deployment tool for Elixir apps that deploys native releases to bare metal servers over SSH. It’s a port of GitHub - basecamp/...
New
Hello everyone. After busy few months I am happy to announce v0.1.0 of Emerge & Solve.
They are GUI (Emerge) and State management (S...
New
Corex is an accessible, unstyled UI component library for Phoenix that integrates Zag.js state machines using Vanilla JavaScript and Live...
New
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #library
- #deployment
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #elixirconf
- #channels
- #exunit
- #discussion
- #code-sync
- #podcasts
- #javascript
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixirconf-us
- #ai
- #blog-post
- #elixir-ls
- #phoenix_html
- #iex
- #graphql
- #genstage
- #websockets
- #supervisor
- #advent-of-code
- #distillery
- #processes
- #api
- #forms
- #hex
- #security
- #metaprogramming










Showing Posts 1 to 1- Show Best Posts
- Show All (oldest first)
- Show All (newest first)
peerreynders
MySQL: locking reads
Given the above information within a short transaction I’d fetch a single job through a
SELECTwith a pessimistic lock (i.e.SELECT ... FOR UPDATE) and update it’s status.You wouldn’t be having this problem if you could re-architecture the background processing - i.e. one process going through the table assigning work to available workers (i.e. get rid of the concurrency issue altogether).