Run rails code after an update to the database has commited, without after_commit

Question

I'm trying to battle some race cases with my background task manager. Essentially, I have a `Thing` object (already exists) and assign it some properties, and then save it. After it is saved with the new properties, I queue it in Resque, passing in the ID. ``` thing = Thing.find(1) puts thing.foo # outputs "old value" thing.foo = "new value" thing.save ThingProcessor.queue_job(thing.id) ``` The background job will load the object from the database using `Thing.find(thing_id)`. The problem is that we've found Resque is so fast at picking up the job and loading the `Thing` object from the ID, that it loads a stale object. So within the job, calling `thing.foo` will still return "old value" like 1/100 times (not real data, but it does not happen often). We know this is a race case, because rails will return from `thing.save` before the data has actually been commit to the database (postgresql in this case). Is there a way in Rails to only execute code AFTER a database action has commit?…

Accepted Answer

You can put in a transaction as well. Just like the example below:

```
transaction do
  thing = Thing.find(1)
  puts thing.foo # outputs "old value"
  thing.foo = "new value"
  thing.save
end
ThingProcessor.queue_job(thing.id)
```

Update: there is a gem which calls After Transaction, with this you may solve your problem. Here is the link: http://xtargets.com/2012/03/08/understanding-and-solving-race-conditions-with-ruby-rails-and-background-workers/

Run rails code after an update to the database has commited, without after_commit

Solution

Problem