[Bug]: Slow Metadata Filtering

[rachel-bousfield]

What happened?

Reopening #1394 per @itaismith 's request:

• [Bug]: Very slow metadata filtering #1394
• [Bug]: Very slow metadata filtering #1394 (comment)

Metadata filters are intractably slow. Even in the simplest case of an $eq filter on a Boolean is orders of magnitude slower than queries without. See @j3ssass 's comment too:

• [Bug]: Very slow metadata filtering #1394 (comment)

[Sukhshum2628]

Hi, I came across this issue while working on a RAG project using ChromaDB
and experienced the same slowdown with metadata filtering on moderate-sized
collections.

I'd like to investigate this further. Before diving into the core filtering
logic, I was thinking of starting with a reproducible benchmark script that
measures query latency across different collection sizes (1k, 10k, 40k, 100k
documents) and filter types ($eq, $gt, $in, $and) — similar to what was done
in PR #2903 but extended to cover more cases and provide clearer regression
data.

This would at minimum give maintainers concrete numbers to work with, and
might help narrow down where the bottleneck sits.

Would a PR in that direction be welcome? Happy to also look at the filtering
implementation itself if someone can point me to the relevant files in the
Rust layer.