skills/redis-development/rules/data-choose-structure.md

title	impact	impactDescription	tags	description	alwaysApply
Choose the Right Data Structure	HIGH	Optimal memory usage and operation performance	data-structures, strings, hashes, sets, lists, sorted-sets, json, streams, vector-sets	Choose the Right Data Structure	true

Choose the Right Data Structure

Selecting the appropriate Redis data type for your use case is fundamental to performance and memory efficiency.

Use Case	Recommended Type	Why
Simple values, counters	String	Fast, atomic operations
Object with fields	Hash	Memory efficient, partial updates, field-level expiration
Queue, recent items	List	O(1) push/pop at ends
Unique items, membership	Set	O(1) add/remove/check
Rankings, ranges	Sorted Set	Score-based ordering
Nested/hierarchical data	JSON	Path queries, nested structures, geospatial indexing with RQE
Event logs, messaging	Stream	Persistent, consumer groups
Similarity search	Vector Set	Native vector storage with built-in HNSW indexing

Incorrect: Using strings for everything.

Python (redis-py):

# Storing object as JSON string loses atomic field updates
redis.set("user:1001", json.dumps({"name": "Alice", "email": "alice@example.com"}))

# To update email, must fetch, parse, modify, and rewrite entire object
user = json.loads(redis.get("user:1001"))
user["email"] = "new@example.com"
redis.set("user:1001", json.dumps(user))

Java (Jedis):

// Bad: Storing as delimited string requires manual parsing
jedis.set("bicycle", "Deimos;Ergonom;Enduro bikes;4972");
String bike = jedis.get("bicycle");
String[] fields = bike.split(";");
String model = fields[0];  // Fragile and error-prone

Correct: Use Hash for objects with fields.

Python (redis-py):

# Hash allows atomic field updates
redis.hset("user:1001", mapping={"name": "Alice", "email": "alice@example.com"})

# Update single field without touching others
redis.hset("user:1001", "email", "new@example.com")

Java (Jedis):

import java.util.Map;
import java.util.HashMap;

// Good: Hash models properties naturally
Map<String, String> hashFields = new HashMap<>();
hashFields.put("model", "Deimos");
hashFields.put("brand", "Ergonom");
hashFields.put("type", "Enduro bikes");
hashFields.put("price", "4972");

jedis.hset("bicycle", hashFields);

// Read individual field
String model = jedis.hget("bicycle", "model");

Reference: Choosing the Right Data Type