u/Good_Expression7538

I’m a third-year CS student and over the past year I’ve been building minidbms — a database engine written from scratch in C and Python — to study buffer pool replacement policies experimentally.

Current features:
- slotted-page heap storage
- direct pread/pwrite I/O
- LRU / Clock / NoCache / OPT
- trace-based telemetry replay
- benchmark + sweep analysis tools
- interactive cache inspector
- B+ tree indexes (in progress)

Some interesting results so far:

- Bélády-related behavior reproduced empirically:
at small pool sizes (3–8 frames), NoCache can outperform LRU.

- LRU stack property verified:
hit rate never decreases as memory increases.

- Working-set convergence:
at 32 frames all policies converge to the same hit rate with zero evictions.

The Cache Inspector (last image) replays every page access step-by-step and shows the full buffer pool state after each event.

Next step:
empirical comparison of shared vs segregated buffer pools for index and data pages.

github.com/rsomavi/minidbms

I’m a third-year CS student and over the past year I’ve been building minidbms — a database engine written from scratch in C and Python — to study buffer pool replacement policies experimentally.

Current features:
- slotted-page heap storage
- direct pread/pwrite I/O
- LRU / Clock / NoCache / OPT
- trace-based telemetry replay
- benchmark + sweep analysis tools
- interactive cache inspector
- B+ tree indexes (in progress)

Some interesting results so far:

- Bélády-related behavior reproduced empirically:
at small pool sizes (3–8 frames), NoCache can outperform LRU.

- LRU stack property verified:
hit rate never decreases as memory increases.

- Working-set convergence:
at 32 frames all policies converge to the same hit rate with zero evictions.

The Cache Inspector (last image) replays every page access step-by-step and shows the full buffer pool state after each event.

Next step:
empirical comparison of shared vs segregated buffer pools for index and data pages.

github.com/rsomavi/minidbms