التزامن والتحكم في التدفق العكسي

Async lets you run many calls at once, but every in-flight task still uses memory and connections. Unbounded concurrency can sink a server. 💥

Backpressure is how a busy server pushes back on incoming work, slowing or queuing it instead of trying to do everything at once.

A semaphore sets a ceiling on how many tasks run in parallel, so the server takes on only as much as it can safely handle.

Give database and HTTP pools a max size. Past it, new calls wait for a free connection rather than opening endless ones.

When you are at capacity, let extra calls queue briefly. Short, bounded waits beat crashing under a sudden burst of requests.

An unbounded queue just hides the overload until memory runs out. Cap the queue length and reject work once it is full.

If the server is saturated, return a clear busy error quickly so the client can retry, rather than letting calls hang forever.

Pair limits with timeouts so a single stuck upstream cannot hold a slot indefinitely and slowly starve every other request.

Track how many tasks are active right now. Rising in-flight counts are your earliest warning that load is outpacing capacity.

Pick limits from measured behavior, not guesses. Load-test, watch latency, and raise or lower caps until the server stays stable.

Done well, backpressure keeps a server stable: it serves what it can, defers the rest, and never tips into a crash.

What does backpressure protect a server from?

You capped parallel work with semaphores, bounded pools and queues, added timeouts, and rejected fast when full, keeping the server healthy. ✅