lance-format / lance-format/lance

Add fast path for btree pages that fully satisfy query

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A-index enhancement
Dominant language
Rust
Stars
7.1k
Forks
852
Avg merge
3d 18h
Merged PRs (30d)
272

Description

Currently we use the min/max of pages to determine which pages we need to search. Then we load those pages and search them with a flat search. Previously this was dominated by I/O time. Now that we are caching btree pages this flat search time could be a considerably part of the query.

We can speed this up by adding a fast path for pages that are obviously completely satisfied. For example, if the page has min=7 and max=11 and the query is foo BETWEEN 0 AND 20 then we know the page is completely matched and we can skip the flat search and just add all the row ids.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by tracing the btree page min/max filtering and the flat search over selected pages. Check how row IDs are collected for a query range, then verify that a page wholly within the range skips flat search while returning the same matching rows. Validate both correctness and the expected reduction in cached-page search work.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
databases
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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