Caching strategies in Supabase - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Cache Invalidation

Which caching strategy ensures that cached data is updated only when the original data changes, minimizing stale data?

A Cache-aside where application checks cache first and updates cache on misses

B Write-through caching where data is written to cache and database simultaneously

C Event-driven invalidation where cache is cleared when data changes occur

D Time-based expiration where cache clears after a fixed time interval

💡 Hint

Think about how the cache knows when to update without waiting for a timer.

Event-driven invalidation updates the cache immediately when data changes, preventing stale data. Other methods rely on time or application checks, which can cause delays.

❓ Architecture

intermediate

Choosing Cache Location for Supabase

You want to reduce latency for users globally accessing your Supabase database. Which caching location provides the best balance between speed and data freshness?

A Edge caching using a CDN close to users

B Client-side caching in the user's browser

C Server-side caching within the Supabase backend

D Database-level caching inside Supabase's Postgres

💡 Hint

Consider where the cache is closest to users and how often data changes.

Edge caching via CDN places cached data near users globally, reducing latency while maintaining reasonable freshness. Client-side caches can be inconsistent, server-side caches add latency, and database caches are less global.

❓ Configuration

advanced

Configuring Cache-Control Headers in Supabase Storage

You want to configure your Supabase Storage bucket to cache images in browsers for 1 day. Which Cache-Control header value achieves this?

A "no-cache, no-store"

B "private, max-age=3600"

C "public, max-age=31536000, immutable"

D "public, max-age=86400"

💡 Hint

1 day equals 86400 seconds. Public means cacheable by browsers and CDNs.

"public, max-age=86400" tells browsers and CDNs to cache the content for 1 day. "private" restricts caching to browsers only, "no-cache" disables caching, and "immutable" is for long-term caching.

❓ security

advanced

Cache Security Risks in Supabase APIs

Which caching practice can lead to exposing sensitive user data when using Supabase APIs?

A Using cache invalidation on data updates

B Caching authenticated API responses without user-specific keys

C Caching public data responses with short expiration

D Encrypting cached data at rest

💡 Hint

Think about what happens if cache stores data for multiple users together.

Caching authenticated API responses without separating by user can cause one user to see another's data. Proper cache keys per user prevent this risk.

❓ service_behavior

expert

Supabase Realtime Cache Behavior

When using Supabase Realtime to listen for database changes, what happens to cached data in your application if you do NOT update the cache on receiving events?

A Cache remains stale until manually refreshed or expired

B Cache automatically updates with new data from Realtime events

C Cache clears itself when Realtime events occur

D Cache duplicates data causing inconsistent reads

💡 Hint

Realtime events notify your app, but do not change cache automatically.

Supabase Realtime sends events but does not modify your cache. Your app must update or invalidate cache on events to keep data fresh.