Pira cara order saka pesen ing Kafka?

Question

Accepted Answer

Kafka njamin **ordering ing siji partisi** nanging **ora ana partisi liyane** — konsep sing penting. Kanggo ngetok ordering kanggo acara sing ana tembung, sampeyan rute menyang partisi sing padha (liwat kunci sing padha). Mangerteni ordering penting kanggo kabenaran.

## Ordering saben partisi

```text
Kafka guarantees:
  ✓ ORDER WITHIN a partition → events in a partition are strictly ordered (by offset);
    consumers read them in order
  ✗ NO order ACROSS partitions → events in different partitions have no relative order
    guarantee (they're processed in parallel by different consumers)
→ this is a FUNDAMENTAL Kafka property (and a common source of misunderstanding)
```

## Ngetok ordering kanggo acara sing ana tembung

```text
To keep RELATED events ordered → send them to the SAME partition:
  → use the SAME KEY for related events (key → hash → same partition):
    e.g. all events for orderId=5 use key=5 → same partition → ordered for that order
  → so per-entity ordering: key by the entity (userId, orderId, accountId)
→ choose the key so events that must be ordered share a partition
```

## Tinitik tukaran lan panimbang

```text
⚠️ Ordering vs PARALLELISM → ordering within a key/partition limits parallelism for that key
  (all of one key's events are processed by one consumer, in order)
⚠️ A few things break ordering: producer retries (without idempotence + max.in.flight=1),
  adding partitions (changes key→partition mapping)
→ if you DON'T need ordering → no key (spread freely for max parallelism)
→ if you NEED ordering → key appropriately; accept the parallelism scope
```

## Mengapa iki penting

Mangerteni message ordering ing Kafka iku migunani amarga **ordering iku konsep Kafka sing fundamental, asring ana salah paham** penting kanggo kabenaran, mula iku pengetahuan sing kudu wujud.

Jaminan ordering Kafka khusus lan penting kanggo dipahami.

Mangerteni **ordering saben partisi** — yen Kafka njamin order **ing partisi** (acara sing ketat diurutake dening offset, dibaca kanthi urut) nanging **ora ana partisi liyane** (acara ing partisi beda ora ana urutan relatif, diproses ing selayang) — iku properti Kafka sing fundamental lan **sumber umum salah paham** (wong asring salah kira global ordering), mula mangerteni iku kanthi bener iku kudu kanggo kabenaran.

Mangerteni cara **ngetok ordering kanggo acara sing ana tembung** — ngirim menyang partisi sing padha kanthi nganggo **kunci sing padha** (mula acara sing ana tembung kaya kabeh acara kanggo order utawa pangguna sing khusus, kunci miturut entitas kasebut, menyang partisi sing padha lan tetep terurut) — iku teknik praktis kunci kanggo nggayuh kabenaran ordering sing dibutuhake aplikasi (per-entity ordering liwat keying).

Mangerteni **tinitik tukaran lan panimbang** — yen ordering ing kunci/partisi **mbatesi parallelism** kanggo kunci kasebut (kabeh acara saka siji kunci diproses dening consumer tunggal kanthi urut), yen sawetara bab ngrusak ordering (producer retries tanpa idempotence lan max.in.flight=1, nambah partisi ngowahi pemetaan kunci), lan yen sampeyan kudu nganggo ora kunci yen ordering ora perlu (kanggo parallelism maksimal) nanging kunci karo becik yen iku (nampa scope parallelism) — cerminan pangerten nuansa sing dibutuhake kanggo ndesain ordering sing bener nalika seimbang parallelism.

Pengetahuan ordering iki penting amarga nggawa salah (kira global ordering, utawa ora kunci acara sing perlu ordering) nyebabake bug kabenaran sejati.

Amarga ordering iku konsep Kafka sing fundamental, asring ana salah paham (per-partition mung, merlokna kunci kanggo ordering acara sing ana tembung) penting kanggo kabenaran, lan amarga mangerteni jaminan, cara nggayuh ordering liwat kunci, lan tinitik tukaran (ordering banding parallelism) kudu wujud, mangerteni message ordering ing Kafka iku migunani, pengetahuan Kafka sing kudu wujud — konsep fundamental, asring ana salah paham sing penting kanggo kabenaran, ing mana mangerteni ordering per-partition lan kunci-based routing kanggo acara sing ana tembung (lan tinitik tukaran parallelism) kudu kanggo ndesain sistem Kafka sing order acara kanthi bener, konsep kunci kabeh pangguna Kafka kudu mangerteni kanthi bener.