umadb-core

Core event store implementation for UmaDB.

Overview

umadb-core provides the low-level storage engine implementation for UmaDB, a high-performance event store built for Dynamic Consistency Boundaries.

This crate handles the critical performance and durability aspects of the event store:

• Append-only event storage with monotonically increasing gapless positions
• Multi-Version Concurrency Control (MVCC) for high-performance non-blocking reads and writes
• Copy-on-write page management for atomic commits and crash safety
• Efficient space reclamation of unreachable page versions
• Tag indexing for fast, precise event filtering
• Optimistic concurrency control to prevent write conflicts
• Full durability before acknowledgements

Architecture

UmaDB uses a custom storage engine with:

• Copy-on-write B+ tree pages for MVCC without blocking
• Atomic header page commits after all data is durably written
• Page reuse tracking to reclaim space from old versions
• Memory-mapped file I/O for high-performance reads
• File I/O and fsync for durability guarantees

Usage

This crate is typically used through higher-level UmaDB components like umadb-server rather than directly. It implements the traits defined in umadb-dcb:

use umadb_core::db::UmaDB;

Performance

The MVCC design enables:

• Non-blocking reads - readers see consistent snapshots without blocking writers
• High-throughput writes - batched append requests amortize disk I/O
• Concurrent access - multiple readers and writers without locks
• Efficient paging - copy-on-write enables atomic updates with minimal copying

Part of UmaDB

This crate is part of UmaDB, a high-performance open-source event store built for Dynamic Consistency Boundaries.

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.