umadb-core 0.5.7

Core event store implementation for UmaDB
Documentation

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:

at your option.