What is Caching?
Caching stores frequently accessed data in fast‑access memory to reduce latency and load on primary storage systems.
- Improves read performance
- Reduces database query volume
- Provides temporary data durability
What is Memcached?
Memcached is an open‑source, in‑memory key‑value store designed solely for caching.
- Simple get/set API
- Volatile storage (data lost on restart)
- Horizontal scaling via sharding
What is ScyllaDB?
ScyllaDB is a high‑performance, distributed NoSQL database compatible with Apache Cassandra.
- Persisted storage on SSDs
- Automatic sharding and replication
- Supports complex queries and secondary indexes
How Do They Differ?
Data Persistence
Memcached stores data only in RAM; ScyllaDB writes to disk, providing durability.
Data Model
Memcached handles simple key‑value pairs; ScyllaDB supports tables, rows, and columns.
Scalability
Both scale horizontally, but ScyllaDB adds automatic load balancing and fault tolerance.
Why Choose Memcached?
- Ultra‑low latency for read‑heavy workloads
- Simple deployment for transient data
- Cost‑effective when data can be regenerated
Why Choose ScyllaDB?
- Need for durable, high‑throughput storage
- Complex query requirements
- Large data sets exceeding RAM capacity
When to Combine Both?
Many architectures use Memcached as a front‑line cache for hot data while persisting the source of truth in ScyllaDB.
- Cache‑aside pattern
- Write‑through or write‑behind strategies