How was cache invalidation done in Redis?

Cache invalidation in Redis is usually done in several ways:

1. Deleting the key — when data in the main database changes, delete the corresponding key from Redis using the DEL command.

2. Setting a Time To Live (TTL) — assign a lifespan to the key, after which it will be automatically removed.

3. Updating the cache — immediately update the value in Redis after data changes.

Example in Python using redis-py:

import redis

r = redis.Redis()

# Invalidate the key
r.delete('user:123')

# Or update with TTL
r.set('user:123', 'new_data', ex=3600)  # key lives for 1 hour