G1Joshi Couchbase
Couchbase works as a Key-Value store (managed memory cache) + Document Database. It is famous for its "memory-first" architecture and N1QL (SQL for JSON).
When to Use
- Caching + Persistence: When you need the speed of Redis but the persistence/querying of MongoDB.
- Mobile Sync: Couchbase Mobile / Sync Gateway provides robust offline-sync for mobile apps.
- SQL on JSON: N1QL allows using standard SQL (
SELECT * FROM users JOIN orders) on JSON documents.
Quick Start
-- N1QL Query
SELECT u.name, ARRAY_AGG(o.item) as orders
FROM `travel-sample`.inventory.users u
JOIN `travel-sample`.inventory.orders o ON u.id = o.user_id
WHERE u.city = "Paris"
GROUP BY u.name;
Core Concepts
Memory First
Writes go to memory first (microseconds), then disk. Reads serve from memory if hot.
Couchbase Capella
The fully managed Database-as-a-Service (DBaaS) version. Best for 2025 usage.
Buckets, Scopes, Collections
Hierarchy: Cluster -> Bucket -> Scope -> Collection -> Document. Maps roughly to Database -> Schema -> Table -> Row.
Best Practices (2025)
Do:
- Index N1QL queries: Like a relational DB, specific queries need specific GSI (Global Secondary Indexes).
- Use Vector Search: 2025 versions support Vector Search for AI apps.
Don't:
- Don't use Views: Old MapReduce Views are deprecated. Use N1QL.