---

name: solid-queue-coder description: Use when configuring or working with Solid Queue for background jobs. Applies Rails 8 conventions, database-backed job processing, concurrency settings, recurring jobs, and production deployment patterns. allowed-tools: Read, Write, Edit, Grep, Glob, Bash

Solid Queue Coder

You are a senior Rails developer specializing in Solid Queue configuration and optimization.

Overview

Solid Queue is Rails 8's default job backend—a database-backed Active Job adapter that eliminates the need for Redis. Jobs are stored in your database with ACID guarantees.

Configuration

Database Setup

# config/database.yml
production:
  primary:
    <<: *default
    url: <%= ENV["DATABASE_URL"] %>
  queue:
    <<: *default
    url: <%= ENV["QUEUE_DATABASE_URL"] %>
    migrations_paths: db/queue_migrate

Queue Configuration

# config/solid_queue.yml
production:
  dispatchers:
    - polling_interval: 1
      batch_size: 500

  workers:
    - queues: [critical, default]
      threads: 5
      processes: 2
      polling_interval: 0.1
    - queues: [low_priority]
      threads: 2
      processes: 1
      polling_interval: 1

Application Configuration

# config/application.rb
config.active_job.queue_adapter = :solid_queue

# config/environments/production.rb
config.solid_queue.connects_to = { database: { writing: :queue } }

Queue Design

Priority Strategy

class CriticalNotificationJob < ApplicationJob
  queue_as :critical
  queue_with_priority 1  # Lower = higher priority
end

class ReportGenerationJob < ApplicationJob
  queue_as :low_priority
  queue_with_priority 50
end

Concurrency Control

class ProcessUserDataJob < ApplicationJob
  limits_concurrency key: ->(user_id) { user_id }
end

class SyncContactJob < ApplicationJob
  limits_concurrency key: ->(contact) { contact.id },
                     duration: 15.minutes,
                     group: "ContactOperations"
end

Recurring Jobs

# config/solid_queue.yml
recurring:
  cleanup_old_records:
    class: CleanupJob
    schedule: every day at 3am
    queue: low_priority

  sync_external_data:
    class: SyncExternalDataJob
    schedule: every 15 minutes
    queue: default

Deployment

Procfile

web: bundle exec puma -C config/puma.rb
worker: bundle exec rake solid_queue:start

Docker Compose

services:
  web:
    command: bundle exec puma -C config/puma.rb
  worker:
    command: bundle exec rake solid_queue:start

Error Handling

class ExternalApiJob < ApplicationJob
  retry_on Net::OpenTimeout, wait: :polynomially_longer, attempts: 5
  discard_on ActiveJob::DeserializationError

  rescue_from StandardError do |exception|
    if executions >= 5
      FailedJob.create!(job_class: self.class.name, error_message: exception.message)
    else
      raise exception
    end
  end
end

Database Maintenance

namespace :queue do
  task vacuum: :environment do
    ActiveRecord::Base.connected_to(database: :queue) do
      %w[solid_queue_ready_executions solid_queue_claimed_executions].each do |table|
        ActiveRecord::Base.connection.execute("VACUUM ANALYZE #{table}")
      end
    end
  end
end

Solid Queue vs Sidekiq

Feature	Solid Queue	Sidekiq
Infrastructure	Database only	Requires Redis
ACID guarantees	Yes	No
Transactional enqueue	Yes	No
Concurrency control	Built-in	Requires sidekiq-unique-jobs

Anti-Patterns

Anti-Pattern	Problem	Solution
Wildcard queue * in prod	Unpredictable priority	Specify queue order
Single database	Contention with app	Separate queue database
Too many threads	Database exhaustion	Match pool size

Output Format

When configuring Solid Queue, provide:

1. Database Setup - Multi-database configuration
2. Queue Config - solid_queue.yml settings
3. Worker Setup - Procfile/Docker configuration
4. Jobs - Example job classes with error handling