Cache invalidation strategies in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is cache invalidation in Redis?

Cache invalidation is the process of removing or updating cached data in Redis to ensure that the cache does not serve stale or outdated information.

beginner

Explain the Time-to-Live (TTL) strategy for cache invalidation.

TTL sets an expiration time on cached data in Redis. When the time expires, Redis automatically removes the cached item, ensuring data is refreshed after a set period.

intermediate

What is the Write-Through cache invalidation strategy?

In Write-Through, data is written to both the cache and the database at the same time. This keeps cache and database synchronized, reducing stale data risk.

advanced

Describe the Write-Back cache invalidation strategy.

Write-Back delays writing data to the database until the cache entry is evicted or updated. This improves performance but risks data loss if cache fails before writing back.

intermediate

What is the Explicit Invalidation strategy?

Explicit Invalidation means manually removing or updating cache entries when the underlying data changes, ensuring the cache always reflects the latest data.

Which Redis feature automatically removes cached data after a set time?

A Write-Back

B Write-Through

C Explicit Invalidation

D Time-to-Live (TTL)

TTL sets an expiration time on cached data, after which Redis deletes it automatically.

In which strategy is data written to cache and database simultaneously?

A Write-Through

B Write-Back

C Explicit Invalidation

D TTL

Write-Through writes data to both cache and database at the same time to keep them synchronized.

Which cache invalidation strategy risks data loss if the cache fails before writing back?

A Write-Through

B Write-Back

C TTL

D Explicit Invalidation

Write-Back delays writing to the database, so data can be lost if cache fails before syncing.

What does Explicit Invalidation require?

A Manual removal or update of cache entries

B Writing data only to database

C Writing data only to cache

D Automatic expiration

Explicit Invalidation means manually removing or updating cache entries when data changes.

Which strategy is best for ensuring cache never serves stale data without manual intervention?

A Explicit Invalidation

B Write-Back

C TTL

D Write-Through

TTL automatically expires cache entries after a set time, preventing stale data without manual steps.

Describe the main cache invalidation strategies used in Redis and when you might use each.

Think about how and when cache data gets updated or removed.

Explain the risks and benefits of Write-Back cache invalidation compared to Write-Through.

Consider speed versus data safety.