CODEWITHSUNDEEP
ruby-on-railssidekiq
Sig
Sig

Reputation: 5986

Sidekiq - pick up DB changes made by another worker

In a Rails app, I have projects which have many tasks. A task may have a predecessor that need to be completed before the task can start.

I use sidekiq for creating tasks.

class ScheduleProjectJob < ApplicationJob
  queue_as :default

  def perform(project)
    tasks = Array(project.tasks)


    while !tasks.empty? do
      task = tasks.shift

      if task.without_predecessor? || task.predecessor_scheduled?
        ScheduleTaskJob.perform_later(task)
      else
        tasks << task
      end
    end
  end

I loop through the tasks and schedule a task if it doesn't have a predecessor or, in case it has one, when the predecessor has been already scheduled.

To check if the predecessor has been scheduled, I check in the database if the predecessor state is scheduled (tasks are created with created state and updated to scheduled at the end of ScheduleTaskJob.

The check is as follows

Task.joins(:task_template).
     where(%q(task_templates.dep_id = :dep AND
              task_templates.tag = :tag AND
              tasks.state = :state),
              specification_id: task_template.dep_id,
              tag: task_template.runs_after_tag,
              state: 'scheduled').
     count > 0

The query above seems to work fine when I manually set the DB up and run it. However, when it runs inside the ScheduleProjectJob the state of the predecessor task is always reported as created even if I can see in the DB the value in the record has been updated to scheduled.

Am I missing anything here?

end

Upvotes: 0

Views: 92

Answers (1)

Vasfed
Vasfed

Reputation: 18474

ActiveRecord caches query results, when you're expecting query result to change, wrap your query with:

ActiveRecord::Base.uncached do # or YourModel.uncached do
  some_query.count
end

Upvotes: 1

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