PallasDB

PallasDB is a key-value database written in Go, built from first principles. It provides crash-safe persistence, sorted string tables, multi-level compaction, a SQL layer, gRPC transport, and Raft-backed replication.

What it is

At its core PallasDB is an LSM-tree storage engine layered with:

• A Write-Ahead Log (WAL) for crash safety
• SSTables (Sorted String Tables) for durable sorted storage
• A merge iterator that unifies multiple sorted levels into a single view
• An MVCC transaction model with snapshot isolation and conflict detection
• A recursive-descent SQL parser and expression evaluator
• A gRPC server for remote key-value access
• A Raft consensus layer (via HashiCorp Raft) for replicated, strongly-consistent writes
• Serf gossip for automatic cluster member discovery

Source layout

Design goals

• Crash-safe by default - every committed write is fsync'd before returning.
• Sorted access - all structures (memtable, SSTables, merge iterators) maintain lexicographic order, enabling efficient range scans.
• Strong consistency in cluster mode - all mutating operations route through the Raft leader; reads can be served locally.
• Self-contained binary - a single pallasdb binary covers local embed, standalone gRPC server, and full Raft cluster node.