Yadda ne ka decide abin da za ka cache da kacal yaya (TTL)?

Question

Accepted Answer

Cache data da **costaffi a samarwa, an karanta sau-sau, kuma ba kasua ba** — wato ne gida da caching an bugi. **TTL** (lokacin rayu) canja tsakanin **shiryewa** (menene kwatancen data) da **sulkewar gida** (menene zafin ajiya da yawancin lokaci).

## Menene za ka cache

Candidate mai kyau don cache yana kan manyan gaba gaida:

- **Costaffi** — haɗawa mai nauyi, tara, kira API na waje, HTML da aka shirya.
- **An karanta sau-sau** — maɓuɓɓugan zafi cire wurare da yawa yana gama-gama kudin.
- **Ba kasua ko kadan** — ko kuma menene raunin da ba shi abin mamaki.

Ka cache abin dan samuwa, rubuta-mai nauyi, ko sirrin mai aiki-gida data cewa ka bugi yiyuwa daidai (misali, akwatin dala a lokacin kasuwa).

## Zabing TTL

```text
Staleness tolerance → TTL:
  config / static reference data   → long  (hours to days)
  product listings, article body   → medium (minutes)
  prices, stock, leaderboards      → short  (seconds)
  must always be exact             → don't cache, or use explicit invalidation
```

Don daidai akai data da ke canja ba alama, haɗa TTL da **fallaci gaskiya**: rubuta-ta gida ko rubuta-on-rubuta yadda cache ya fadi tashe a maimakon jiran sakewa.

```text
on update(record):
  db.save(record)
  cache.delete(key(record))   // invalidate now, don't serve stale until TTL
```

## Alamar: ƙarfin baje wuraren

```text
hit ratio = hits / (hits + misses)
  high (>90%) → cache is doing its job
  low         → TTL too short, keys too granular, or data not cacheable
```

Kalli **cache hit ratio** don tune TTLs: rauni kaɗan yana nufin ba ka caching ba; rauni mai girma tare da daidai-daidai yana nufin TTLs suna da tsayi.

## Menene ya sa wannan muhimmi

Samun menene za ka cache da TTL daidai ne ainihin caching maidowa. Cache abubuwa mara kyau da kuma ka ƙara hadaddiya ba tare da anfani ba; sai da TTLs da tsayi kuma ka ba da tsoffin data; gida mai laushi da kuma ba ka taba anfani. Amfani da sulkewar gida don zabing TTLs, sai da fallaci gaskiya don daidai, da kalli rauni ya ba ka hanya da ma'anar samu, asusuwa na cache.