COMPLETED · MAR 2026 · ECS 165A
LStore: Column-Oriented Database Engine
Built a full column-oriented database system from scratch over a quarter. Implemented B+ tree indexing, a buffer pool, page-range tables, a full query engine, and 2PL concurrency control. Scored 10/10 on all test suites with 1000/1000 concurrent transactions and a "Great Performance" rating from the grader.
THE STORY
A full database from the disk layer up. The hardest part wasn't the B+ tree; it was no-wait concurrency under contention. Every locking decision had to be correct under thousands of concurrent reads and writes, with rollback semantics that left the data consistent. By the time the test suite hit 10/10 with full concurrency and a "Great Performance" benchmark, I felt like I actually understood why production databases are so careful.
FEATURES
Disk Persistence
Page files + metadata serialized to disk with crash recovery
Buffer Pool
LRU/MRU eviction policy with a 1000-page in-memory cache
Page Range Tables
Base + tail record architecture for efficient updates
Query Engine
Full CRUD + aggregation + record versioning
Transactions
2PL no-wait locking with rollback on conflict
Concurrency
1000 of 1000 concurrent transaction tests passed
CODE
REPO TBA — being cleaned up for public release