threads 8 # Match CPU cores (data threads)
server-threads 2 # I/O threads (accept connections)
active-replica yes # For Active-Active
storage-provider rocksdb # Tiered storage (Flash/SSD)
maxmemory-policy allkeys-lru
The single most important differentiator in KeyDB engineering is its threading architecture. Redis uses a single event loop; if one operation is slow (e.g., KEYS *), the entire server blocks.
KeyDB introduces three distinct thread types:
active-replica yes
| Metric | KeyDB (16 threads) | Redis (single thread) | |--------|--------------------|----------------------| | Ops/sec (SET/GET, 50/50) | ~2.4M | ~0.5M | | P99 latency (high concurrency) | 0.8ms | 2.5ms | | Memory overhead per key | ~72 bytes | ~80 bytes |
Figures approximate – hardware dependent (48 cores, 100GbE) keydb eng
Standard Redis replication is master-replica (passive). KeyDB introduces Active-Replica:
From an engineering ops perspective, KeyDB is designed as a literal drop-in replacement: threads 8 # Match CPU cores (data threads)
Migrating typically involves:
# Stop Redis, install keydb, point to same config
sudo systemctl stop redis
sudo apt install keydb # or from source
sudo keydb-server /etc/redis/redis.conf
No application code changes required. That’s the killer feature. Migrating typically involves: # Stop Redis, install keydb,
To avoid locking overhead on read-heavy workloads, KeyDB implements optimistic locking for read operations.
This transforms read latency from O(lock_contention) to O(1) in most cases, at the cost of rare retries.