name	database-redis
description	Optimize Redis caching, key management, and performance. Use when implementing Redis caching strategies, managing key namespaces, or optimizing Redis performance.
metadata	{"triggers":{"files":["*/.ts","*/.js","**/redis.config.ts"],"keywords":["redis","cache","ttl","eviction"]}}

Redis Best Practices

Security:
Access Control: Use Redis 6.0+ ACLs (ACL SETUSER) to restrict commands by user/role.
Encryption: Always enable TLS for data-in-transit (standard in managed Redis like Azure/AWS).
Dangerous Commands: Disable or rename FLUSHALL, KEYS, CONFIG, and SHUTDOWN in production.
Connection Resilience:
Pooling: Use connection pooling with tuned high/low watermarks to avoid connection churn.
Timeouts: Set strict read_timeout and connect_retries to handle transient network saturation.

Key Design:
Namespacing: Use colons to namespace keys (e.g., app:user:123, rate:limit:ip:1.1.1.1).
Readability vs Size: Keep keys descriptive but compact; avoid keys > 512 bytes.
Commands & Performance:
O(N) Avoidance: Use SCAN instead of KEYS. Use UNLINK instead of DEL for background reclamation of large keys.
Lua Scripting: Prioritize EVALSHA for atomic logic; ensure scripts pre-loaded to save bandwidth.
Massive Range: Limit ZRANGE, HGETALL, and LRANGE results with offsets/limits.
Memory Management:
Eviction Strategy: Use allkeys-lru for general caches and volatile-lru for mixed persistent/ephemeral data.
Lazy Freeing: Enable lazyfree-lazy-eviction and lazyfree-lazy-expire (Redis 4.0+) to offload cleanup from main thread.
Monitoring: Watch Used Memory RSS vs Used Memory Dataset. Large fragmentation suggests need for MEMORY PURGE or scaling.

No sole truth in Redis: Always persist critical data to durable primary database.
No large blobs: Split values > 100KB into smaller keys or use Hashes for field access.
No JSON for objects: Use HSET for object fields to enable O(1) access without full decode.
No TTL-less keys: Set TTL or eviction policy on all non-permanent keys to prevent unbounded growth.

Redis Best Practices

Priority: P0 (CRITICAL)

Security:

Access Control: Use Redis 6.0+ ACLs (ACL SETUSER) to restrict commands by user/role.

Encryption: Always enable TLS for data-in-transit (standard in managed Redis like Azure/AWS).

Dangerous Commands: Disable or rename FLUSHALL, KEYS, CONFIG, and SHUTDOWN in production.

Connection Resilience:

Pooling: Use connection pooling with tuned high/low watermarks to avoid connection churn.

Timeouts: Set strict read_timeout and connect_retries to handle transient network saturation.

Guidelines

Key Design:

Namespacing: Use colons to namespace keys (e.g., app:user:123, rate:limit:ip:1.1.1.1).

Readability vs Size: Keep keys descriptive but compact; avoid keys > 512 bytes.

Commands & Performance:

O(N) Avoidance: Use SCAN instead of KEYS. Use UNLINK instead of DEL for background reclamation of large keys.

Lua Scripting: Prioritize EVALSHA for atomic logic; ensure scripts pre-loaded to save bandwidth.

Massive Range: Limit ZRANGE, HGETALL, and LRANGE results with offsets/limits.

Memory Management:

Eviction Strategy: Use allkeys-lru for general caches and volatile-lru for mixed persistent/ephemeral data.

Lazy Freeing: Enable lazyfree-lazy-eviction and lazyfree-lazy-expire (Redis 4.0+) to offload cleanup from main thread.

Monitoring: Watch Used Memory RSS vs Used Memory Dataset. Large fragmentation suggests need for MEMORY PURGE or scaling.

Anti-Patterns

No sole truth in Redis: Always persist critical data to durable primary database.

No large blobs: Split values > 100KB into smaller keys or use Hashes for field access.

No JSON for objects: Use HSET for object fields to enable O(1) access without full decode.

No TTL-less keys: Set TTL or eviction policy on all non-permanent keys to prevent unbounded growth.

References

database-redis