Apa bedane antarane layanan stateful lan stateless?

Question

Accepted Answer

**Stateless** services ora nyimpen client state antarane requests (saben request independent), dene **stateful** services maintain state. Statelessness penting banget kanggo scalability — stateless services luwih gampang di-scale horizontally.

## Stateless vs stateful

```text
STATELESS → the service keeps NO client state between requests:
  → each request contains all needed info; any server can handle any request
  → state lives ELSEWHERE (database, cache, client, token) if needed
STATEFUL → the service MAINTAINS state across requests:
  → a specific server holds a client's state (session in memory, etc.)
  → requests must go to the SAME server (or state must be shared/synchronized)
```

## Napa statelessness membantu scalability

```text
STATELESS services scale horizontally EASILY:
  → any server handles any request → load balancing is simple (any server works)
  → add/remove servers freely; a failed server doesn't lose state → resilient
  → no sticky sessions or state synchronization needed
STATEFUL services are HARDER to scale:
  → requests tied to specific servers (sticky sessions); a server failure loses its state;
    scaling needs state sharing/replication → complexity
→ PREFER STATELESS services for scalability (a key design principle).
```

## Handling state ing stateless designs

```text
→ Store state EXTERNALLY where servers can share it:
  → SESSION/data in a shared store (Redis, database) → any server reads it
  → state in the CLIENT (e.g. JWT tokens carry auth state)
  → keep services stateless; externalize state → scalable AND maintains needed state
```

## Napa iki penting

Paham beda antarane stateful lan stateless services iku foundational banget, amarga **statelessness iku key principle kanggo membangun scalable systems**, dadi iki essential system-design knowledge.

Bedane — **stateless** services ora keep client state antarane requests (saben request independent, server apa wae bisa handle request apa wae) versus **stateful** services maintain state (tied to specific servers) — iki fundamental kanggo cara services scale.

Paham **napa statelessness help scalability** iku crucial insight: stateless services scale horizontally gampang banget amarga **server apa wae bisa handle request apa wae** (load balancing dadi simple, servers bisa ditambah utawa dikurangi freely, lan failed server ora ilang state — resilient), dene stateful services jauh luwih angel scale (requests tied to specific servers via sticky sessions, server failures ilang state, scaling butuh complex state sharing).

Makane **prefer stateless services iku key design principle** kanggo scalability — iku isa paling penting practical concept in designing scalable systems.

Paham carane **handle state ing stateless designs** — store state eksternal di mana servers bisa share iku (sessions in shared store kaya Redis, utawa state in client-side tokens kaya JWTs) supaya services tetep stateless nanging tetep maintain needed state — iki practical technique sing reconcile statelessness karo applications sing butuh state.

Iki connect ke horizontal scaling lan load balancing (sing work best karo stateless services).

Amarga statelessness iku key enabler ng horizontal scalability (main approach kanggo large-scale systems) lan paham stateless/stateful distinction, napa statelessness aid scaling, lan carane externalize state iku fundamental kanggo designing scalable systems, paham stateful vs stateless services iku essential, foundational system-design knowledge — iku key principle kanggo scalability (statelessness enabling easy horizontal scaling), connecting ke load balancing lan horizontal scaling, lan central kanggo designing systems sing scale, iku important concept underlying scalable architecture.