Background Jobs Explained: Keeping Your Website Running Smoothly

What are Background Jobs?

Imagine you’re working on a school project, and you need to print out a huge report. Instead of waiting by the printer until it's done, you start the printing process and continue working on other parts of your project. The printer works in the "background" while you do other things.

In the world of computers, a "background job" works similarly. It's a task that runs in the background so that the main application can continue running smoothly without waiting for that task to finish.

Background jobs are tasks that run separately from the main part of a website.

When to Use Background Jobs

• Long-running tasks: Like sending lots of emails or creating big reports
• Tasks that can wait: Things that don't need to happen right away
• Repetitive tasks: Jobs that need to be done regularly, like cleaning up old data

When Not to Use Background Jobs

• Quick tasks: If something takes less than a second, it's usually fine to do it right away
• Tasks that need an immediate response: Like showing a user their account balance

Common Problems

• Jobs taking too long: This can slow down the whole system
• Failed jobs: Sometimes jobs crash and need to be retried
• Too many jobs at once: This can overload the system

Popular Background Job Tools

Two popular tools for managing background jobs are Sidekiq https://github.com/sidekiq/sidekiq and Resque https://github.com/resque/resque.

Similarities

• Both are background job processors for Ruby
• Both use Redis as a backend store
• Both support job prioritization
• Both allow for job scheduling

Differences

Sidekiq

• Uses threads for concurrency
• Supports real-time prioritization
• Has a smaller memory footprint

Resque

• Uses processes for concurrency
• Simpler architecture
• Better isolation between jobs

Threads

• Lightweight
• Share memory space
• Faster to create and switch between
• Less isolated
• Can lead to race conditions
• Suitable for I/O-bound tasks

Processes

• Heavier weight
• Separate memory space
• Slower to create and switch between
• More isolated
• Better for CPU-bound tasks
• More stable if one crashes

Advantages

Sidekiq

• Higher performance and throughput
• More memory efficient
• Built-in web UI for monitoring
• Supports job batches and unique jobs

Resque

• Simpler to understand and debug
• Better job isolation (separate processes)
• Wider plugin ecosystem
• Easier to integrate with non-Rails apps

Disadvantages

Sidekiq

• More complex to set up and configure
• Potential for race conditions due to threading
• Requires more careful coding to avoid thread safety issues

Resque

• Lower performance compared to Sidekiq
• Higher memory usage due to process-based architecture
• Lacks some advanced features like real-time prioritization

Read more: Speed Up Your Ruby App: Background Processing with Sidekiq https://vulehuan.com/en/blog/2024/6/speed-up-your-ruby-app-background-processing-with-sidekiq-667b891ab7287dd8720a3a95.html