DuckDB community extension for prefiltered HNSW using ACORN-1
Get picks like this daily. Today's launch numbers, the top launches, AI and tech news, and a daily opportunity pick, straight to your inbox.
Want to reach these readers? Sponsor an issue.
Hey folks! As someone doing hybrid search daily and wishing I could have a pgvector-like experience but with actual prefiltered approximate nearest neighbours, I decided to just take a punt on implementing ACORN on a fork of the DuckDB VSS extension. I had to make some changes to (vendored) usearch that I'm thinking of submitting upstream. But this does the business. Approximate nearest neighbours with WHERE prefiltering.Edit: Just to clarify, this has been accepted into the community extensions repo. So you can use it like:```INSTALL hnsw_acorn FROM community;LOAD hnsw_acorn;```
HN · launched Mar 25, 2026 · 90 upvotes (top 10%) · 0 views
Niche: database management systems and engines · 162 launches, 5 in the last 7 days ▼ -17% · Explore this niche →
Category and tags
- Horizontal
- Search & retrieval
- Developer
- Not AI
- Hobby / open-source project
Visit website ↗ Source listing ↗
More like this: all 162 launches in database management systems and engines →
Could you build this?
No Implementing the ACORN algorithm for prefiltered vector search inside a C++ DuckDB/usearch extension requires deep low-level algorithm implementation and database engine internals knowledge.
What it would actually take: This requires modifying low-level C++ codebases (vendored usearch and DuckDB VSS) to implement graph-based approximate nearest neighbor search (ACORN-1) with custom predicate traversal logic during HNSW construction and search. The engineer must understand vector index graph invariants, cache-friendly SIMD distance metrics, and DuckDB's execution engine memory model and extension APIs. This necessitates specialized expertise in database systems internals and advanced vector search algorithmic research.
Discussion
5 comments analyzed.
Competitors mentioned: DuckDB with Lance extension, RaBitQ
Concerns raised: Performance with strict filters affecting speed vs accuracy tradeoff
Feature requests: Efficient binary vectors support, Upstream integration
Competitors
Other products that read as similar to this one : 35 launches clear the similarity bar, closest 8 shown.
Attention rank: #3 of 36 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).
Launched 124 days after the earliest competitor.
- Ducktape · hn · 2025-12-16 · 12 upvotes · similarity 0.42
- Glintlog · hn · 2026-02-04 · 10 upvotes · similarity 0.40
- Connect DuckDB to any database that has an ADBC driver · hn · 2026-07-08 · 7 upvotes · similarity 0.40
- Dux, distributed DuckDB-backed dataframes on the Beam · hn · 2026-03-31 · 7 upvotes · similarity 0.38
- Ducklang: Achieving 100x more requests per second than NextJS · hn · 2026-01-01 · 9 upvotes · similarity 0.35
- acorn · hn · 2026-02-24 · 5 upvotes · similarity 0.35
- Snowflake Emulator · hn · 2026-01-03 · 6 upvotes · similarity 0.35
- Local Privacy Firewall-blocks PII and secrets before ChatGPT sees them · hn · 2025-12-09 · 111 upvotes · similarity 0.34
The niche, labels, vibe code rating and competitor comparison on this page are analysis by Nicheloom. If you use them, please credit nicheloom.com. How you may use our data.