bplustree on HackerShow

Data

embedded key-value storage

SHOW HN2018

On-disk B+ tree for Python 3

Shown by nicolaslem on Jan 21, 2018. Click the card to turn it over.

159points

21comments

#246of 2,155 in 2018

Top 12%of 2018 by points

How HN took it

CuriousMostly questions and neutral comments

1 positive, 4 neutral or asking, 1 mixed, 2 critical, out of 8 comments about the project. Thread score -0.04.

Execution: 1 for, 1 againstDocs: 0 for, 1 against

Each row is a top-level comment and its replies, in HN's order. Select a cell to open that comment on HN.

positive neutral or mixed critical about another commenter or something else the maker

Code is clean and uses type annotations
From 1 comment
- The code looks very clean. Uses type annotations too. Wish there were more comments though.
  sprt on HN

Delete not implemented yet (work in progress on remove branch)
From 2 comments
- Cannot delete items yet
  antman on HN
- Yes, it's a work in progress, see the `remove` branch.
  nicolaslem on HN
Likely an order of magnitude slower than LMDB; CPU intensive object creation
From 1 comment
- I haven't done any benchmark yet but I expect my implementation to be at least an order of magnitude slower. I've found my implementation to be CPU intensive: creating Python…
  nicolaslem on HN
Overflow pages are not collected, so file can grow without bounds
From 1 comment
- Why is this not mentioned very clearly in the README? Seems like willful misrepresentation. You might also mention that, if replacing large values that use overflow pages, the…
  coleifer on HN
Serialization is too complicated
From 1 comment
- Thank you. I know what you mean, I'm not happy with how the serialization is done right now, it's too complicated. Maybe someone on HN knows a Python serialization library beyond…
  nicolaslem on HN

Document serialization formats and WAL with diagrams
From 1 comment
- This is pretty cool. As I was reading the code I really wished for an explanation or simple ASCII diagram of the serialization formats for the various node/record types, as well…
  coleifer on HN
More code comments
From 1 comment
- The code looks very clean. Uses type annotations too. Wish there were more comments though.
  sprt on HN

How does it compare to LMDB?
From 1 comment
- Nice, I'm a big user of various data stores for scientific work. How does this compare to LMDB (http://www.lmdb.tech/doc/), which uses B-trees (and has a Python interface)?
  dimatura on HN
How does it perform compared to sqlite3?
From 1 comment
- How does this perform compared to sqlite3? And and can you use keys that aren't builtin values?
  erezsh on HN
Can non-builtin keys be used?
From 1 comment
- How does this perform compared to sqlite3? And and can you use keys that aren't builtin values?
  erezsh on HN

ZODB BTrees package
From 1 comment
- ZODB has a mature B+Tree implementation for on disk use in the BTrees package. https://pypi.python.org/pypi/BTrees
  laurencerowe on HN
LMDB
From 2 comments
- Nice, I'm a big user of various data stores for scientific work. How does this compare to LMDB (http://www.lmdb.tech/doc/), which uses B-trees (and has a Python interface)?
  dimatura on HN
- What's wrong with LMDB?
  halayli on HN
SQLite
From 1 comment
- How does this perform compared to sqlite3? And and can you use keys that aren't builtin values?
  erezsh on HN
Durus
From 1 comment
- Check out zodb and durus.
  shalabhc on HN