# Concurrency and queues

Sydekyks user and operator guide. Check feature availability and release-specific installation requirements.

Concurrency is the number of jobs that can execute at the same time. When capacity is occupied, new work can wait in the queue rather than execute immediately.

## ​Interpret a delay

Check whether a run is queued, executing or paused inside the mission. A busy execution queue, a provider rate limit and a human approval pause require different responses.

## ​Worker capacity

Operators set worker concurrency and replica counts for the deployment. The underlying source default for AP_WORKER_CONCURRENCY is 5. A concurrency of 1 with separate resource-capped worker containers gives a different isolation boundary from five jobs sharing one worker.

Use production setup (https://docs.sydekyks.com/install/configure-operate/production-setup) and worker architecture (https://docs.sydekyks.com/install/architecture/workers) to choose capacity. More workers do not remove an external provider’s quota.

## ​Command Center limits

Some builds expose a per-project maximum concurrent jobs setting. Confirm that it is supported and enforced before relying on it. Native embedding JWT concurrency pools and worker-group assignment are excluded from the initial Community guide.

## ​Investigate persistent queues

Check worker health, database and Redis reachability, error logs and job volume. A queued job cannot progress without functioning workers and its required infrastructure. Use the queue dashboard (https://docs.sydekyks.com/install/troubleshooting/bullboard) when configured.