Menene CAP theorem?

Question

Menene CAP theorem?

Accepted Answer

**CAP theorem** ya bayyana cewa tsarin rarraba zai iya garantama a mafi yawa **biyu daga cikin ukku** kadarori — **Consistency**, **Availability**, da **Partition tolerance** — a lokaci gida. Tun da raunin sadarwa ba za su iya guje ba, ainihin zaɓi shine tsakanin consistency da availability lokacin da aka samu raunin sadarwa.

## Kadarorin ukku

```text
CONSISTENCY (C) → every read sees the latest write (all nodes agree on the data)
AVAILABILITY (A) → every request gets a response (the system stays responsive)
PARTITION TOLERANCE (P) → the system keeps working despite network partitions
  (communication breaks between nodes)
→ CAP: you can only fully guarantee TWO of these three simultaneously.
```

## Ainihin ƙwalaƙwalo: C da A (P shine abin tilas)

```text
In distributed systems, network PARTITIONS WILL happen → P is NOT optional (you must
tolerate partitions) → so the real choice during a partition is C vs A:
  CP (consistency over availability) → during a partition, refuse requests that can't be
    consistent (sacrifice availability to keep data correct) — e.g. financial systems
  AP (availability over consistency) → during a partition, stay available but may return
    stale/inconsistent data (eventual consistency) — e.g. social feeds, many NoSQL stores
→ choose based on whether CONSISTENCY or AVAILABILITY matters more for the use case.
```

## Fahimta da aiki

```text
→ CAP is about behavior DURING a partition (normally you can have both C and A)
→ It's not strictly binary → many systems offer TUNABLE consistency (per-operation choices)
→ Related: EVENTUAL CONSISTENCY (AP systems converge to consistency over time)
→ Understand the trade-off to choose databases/designs appropriately
```

## Me yasa ya ringyama

fahimta CAP theorem ta kasance mai mahimmanci saboda ita ce **jigon ilimin tsarin rarraba** da ke haifar da wani mahimmacin ƙwalaƙwalo, don haka ita ce mahimman ilimin tsarin ƙira.

CAP theorem — cewa tsarin rarraba zai iya garantama a mafi yawa biyu daga cikin Consistency, Availability, da Partition tolerance a lokaci gida — ya kunna wani ƙalubale na asali a cikin tsarin rarraba.

fahimta **kadarorin ukku** (consistency: karanta suna ganin sabuwar rubutu; availability: kowane buƙatun ya samu amsa; partition tolerance: aiki simu daga raunin sadarwa) shine asali.

Mafi mahimmaci, fahimta **ainihin ƙwalaƙwalo** shine mabuɗin mahimmaci a aiki: tun da **raunin sadarwa ba za su iya guje ba** a cikin tsarin rarraba (P shine abin tilas), ainihin zaɓi lokacin da aka samu raunin sadarwa shine tsakanin **consistency da availability** — **CP systems** suka yi alfahari wajen gaida data daidai lokacin raunin sadarwa (mai dacewa da tsarin kuɗi inda daidaito shi ke mahimmi), yayin da **AP systems** suke da zaɓen samuwa amma suna iya aika da tsofaf bayani (eventual consistency, mai dacewa da shafukan jama'a da yawa NoSQL waje inda samuwa ya kasance mafi mahimmaci).

fahimta C-da-A ƙwalaƙwalo da zaɓi dangane da ko consistency ko availability ya kasance mafi mahimmi ga abin da ake bukata shine abin tilas don ƙira tsarin rarraba da zaɓin databases da dacewa.

fahimta **fahimta** — cewa CAP shine game da aiki lokacin da aka samu raunin sadarwa (zai iya kasancewa da C da A a yau), cewa ba shi ne santsi binary (jama'a da yawa a tsarin rarraba suna bayar da tunable consistency), da jigon ilimin eventual consistency — ya nuna fahimta da ya yi gajeren baki fiye da ƙarancin siƙa.

CAP shine jigon ilimin asali da yake abin tabbatarwa a ƙira tsarin rarraba da zaɓin database.

Tun da CAP theorem ya haifar da wani ƙalubale na asali a cikin tsarin rarraba (consistency da availability lokacin raunin sadarwa) da ke ba da shawarwari ga ƙira tsarin rarraba da zaɓin database, da tun da fahimta kadarorin, ainihin C-da-A ƙwalaƙwalo, da fahimta ta mahimmanci ne don ƙira tsarin rarraba, fahimta CAP theorem ta kasance mai mahimmanci, aiki da dacewa ilimin ƙira — jigon ilimin tsarin rarraba na asali da ke haifar da consistency-availability ƙwalaƙwalo, mahimmanci ne don ƙira tsarin rarraba da zaɓin database, da abin tabbatarwa a ƙira tsarin rarraba da ke nuni da fahimta ƙalubale na tsarin rarraba.