lance-format / lance-format/lance
Don't materialize any data on `count_rows` if the filter can be satisfied by a scalar index
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- Dominant language
- Rust
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- Merged PRs (30d)
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Description
If we can satisfy a filter with a scalar index then we should be able to implement a fast path for count_rows where we simply return the size of the allow_list or even possibly subtract the size of the block_list from the metadata-only count_rows (might be some tricky bits if there are deletion vectors) to quickly answer queries like count_rows("x != 'foo'").
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by tracing the count_rows path and scalar-index filter handling, with deletion-vector behavior in scope. Done means count_rows avoids materializing data when the filter is satisfied by a scalar index and returns a correct count for allow_list and block_list cases.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- databases, performance
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 48/100