As we discussed in earlier chapters that SolidQueue is engineered to align tightly with the ethos of Rails — simplicity, convention over configuration, and seamless integration.

Unlike other background job systems like Sidekiq that rely on external components like Redis, SolidQueue operates using your existing SQL database.

This approach not only reduces deployment complexity but also enables developers to trace job lifecycles using familiar tools like migrations, models, and logs.

SolidQueue's architecture is built on tables and queries that manage job queues, workers, and scheduling — all while leveraging the safety and atomicity of transactional databases. Understanding this internal structure allows you to appreciate how jobs are enqueued, picked, locked, processed, and eventually marked as completed — all with minimal operational overhead.

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The architectural decisions behind SolidQueue have profound implications for developers and operations teams alike. By integrating background processing into the heart of the Rails application — the database — SolidQueue eliminates the “second system syndrome” that arises when managing and monitoring Redis-based workers separately.

This design simplifies deployment pipelines, improves local development fidelity, and creates more predictable system behavior.

Additionally, SolidQueue’s use of modern SQL features (like FOR UPDATE SKIP LOCKED) makes it efficient in multi-threaded, concurrent environments.

In this chapter, we’ll peel back the layers of SolidQueue’s internal architecture, explaining how jobs are stored and picked up, how queues are managed, how workers operate in parallel, and how everything ties back into ActiveJob — the standard Rails interface for background jobs.