Redis Core

Redis Core

Foundational guidance for modeling data in Redis. Covers data-type selection and key-name conventions — the two decisions that most directly drive memory, performance, and maintainability.

When to apply

• Caching objects, sessions, or per-user state.
• Counters, leaderboards, recent-items lists, unique-membership sets.
• Reviewing or refactoring Redis key names.
• Deciding between a Redis Hash and a JSON document for an entity.

1. Choose the right data structure

Pick the type that matches the *access pattern*, not just the shape of the data.

| Use case | Recommended type | Why |

|---|---|---|

| Simple values, counters | String | Atomic INCR/DECR, SET/GET |

| Object with independently updated fields | Hash | Per-field reads/writes, no whole-object rewrite |

| Queue, recent-N items | List | O(1) push/pop at ends |

| Unique items, membership checks | Set | O(1) SADD/SISMEMBER/SCARD |

| Rankings, score-based ranges | Sorted Set | Score-ordered; ZADD/ZRANGE/ZRANK |

| Nested / hierarchical data | JSON | Path-level updates, nested arrays, RQE indexing |

| Event log, fan-out messaging | Stream | Persistent, consumer groups |

| Vector similarity | Vector Set | Native vector storage with HNSW |

Common anti-pattern: stuffing a flat object into a serialized string. Updating one field means fetch + parse + mutate + rewrite. Use a Hash instead.

See references/choose-data-structure.md for full rationale and Python/Java examples.

2. Use consistent key names

Use colon-separated segments with a stable hierarchy:

{entity}:{id}:{attribute}
user:1001:profile
user:1001:settings
order:2024:items
session:abc123
article:987:likes
game:space-invaders:leaderboard

Rules of thumb:

• Lowercase, colon-separated. No spaces, no mixed casing (User_1001_Profile is bad).
• Keep keys short but readable — keys live in memory and appear in every command.
• Don't use full URLs or long strings as keys. Extract a short identifier, or use a hash digest of the URL.
• Prefix for multi-tenancy (tenant:42:user:7:cart) so scans and ACLs can target a tenant cleanly.
• Be consistent. Pick one convention per service and apply it across all keys.

See references/key-naming.md for cleanup examples and edge cases.

References

• Redis: Choosing the right data type
• Redis: Keys