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mid

How does the Cache-Aside (Lazy Loading) pattern work?

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midcaching

The application checks the cache -> on miss, reads from the DB -> writes to the cache.

The most popular caching pattern. Read: check cache -> cache hit -> return. Cache miss -> read DB -> write to cache -> return. Write: update DB -> invalidate cache. Lazy loading: only requested data is cached. Stale data is possible between updating the DB and invalidating the cache.

// Cache-Aside pseudo-code
async function getData(key) {
  let data = await redis.get(key);
  if (!data) {
    data = await db.query(key);
    await redis.set(key, data, 'EX', 3600);
  }
  return data;
}

Когда да

Read-heavy workloads, data changes infrequently, tolerance for eventual consistency

Когда нет

Data changes frequently and strict consistency is required

Совет на собеседовании

This is the default pattern — if not specified otherwise, use Cache-Aside

Альт:Write-ThroughWrite-BehindRead-Through

Свайп вправо — знаю, влево — не знаю

ArchCase

ArchCase

Кэширование

The application checks the cache -> on miss, reads from the DB -> writes to the cache.