Compare the cache-aside, write-through, and write-back caching strategies. What are the key trade-offs in consistency vs. latency?
Python interview question for Advanced practice.
Answer
1. Cache-Aside: The app checks the cache. On miss, it reads from the DB, then updates the cache. Most common but puts the logic burden on the app. 2. Write-Through: The app writes to the cache, and the cache synchronously updates the DB. Ensures consistency but adds write latency. 3. Write-Back: The app writes to the cache only. The cache asynchronously flushes data to the DB later. Provides best write performance but risks data loss on cache failure.
Explanation
Write-back (or write-behind) offers the lowest latency but risks data loss if the cache server fails before flushing to the DB.