[RFC] What filtered search algorithms should DiskANN support? by magdalendobson · Pull Request #1128 · microsoft/DiskANN

magdalendobson · 2026-06-02T21:00:36Z

This PR adds an RFC on which filtered search algorithms the DiskANN repo should support.

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Pull request overview

Adds an RFC documenting an empirical evaluation of DiskANN filtered-search algorithm variants, with a recommendation for which algorithms the repo should support going forward.

Changes:

Introduces a new RFC describing existing and proposed filtered-search algorithms (inline, beta, multi-hop, two-queue, adaptive-L).
Records benchmark results on two datasets (Caselaw and YFCC) with accompanying plots.
Proposes a path forward: add inline (optionally adaptive-L), retain multi-hop, deprecate beta, and close two-queue.

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codecov-commenter · 2026-06-02T21:16:22Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.45%. Comparing base (68cc3c4) to head (0d4eadb).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1128      +/-   ##
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- Hits        81868    81767     -101     
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Flag	Coverage Δ
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unittests	`89.10% <ø> (+0.57%)`	⬆️

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…soft/DiskANN into users/magdalen/filtered_search_rfc

harsha-simhadri · 2026-06-02T22:51:54Z

Could this be in the wiki? The plots are a quite large addition to the repo.

magdalendobson · 2026-06-03T13:14:26Z

Could this be in the wiki? The plots are a quite large addition to the repo.

Do we want an RFC that points to benchmarks in the wiki then? Because folks were pretty clear that they wanted an RFC on filtered search.

magdalendobson · 2026-06-03T14:46:40Z

Could this be in the wiki? The plots are a quite large addition to the repo.

Do we want an RFC that points to benchmarks in the wiki then? Because folks were pretty clear that they wanted an RFC on filtered search.

I have moved the benchmark discussion section to the DiskANN wiki: https://github.com/microsoft/DiskANN/wiki/Evaluation-of-Filtered-Search-Algorithms

arrayka

LGTM. Approving, assuming the QPS and latency comparison between Adaptive L and the beta filter for disk search scenarios looks promising.

suri-kumkaran

Thanks for the great work. The RFC recommendations around deprecating beta filter, adding inline filtered search, and adding adaptive L search make sense to me.

One follow up implementation question is how we should expose these similar and overlapping algorithms at the right level of granularity, so clients can reuse them through providers, with or without their own query planners, depending on their use cases.

This PR implements the recommendation in the [filtered search RFC](#1128) to implement inline filtering with the adaptive L method as an optional addition. --------- Co-authored-by: qingcha chen <qinchen@microsoft.com> Co-authored-by: Magdalen Manohar <magdalen@magdalen.localdomain> Co-authored-by: Magdalen Manohar <mmanohar@microsoft.com> Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com> Co-authored-by: Mark Hildebrand <hildebrandmw@gmail.com> Co-authored-by: Mark Hildebrand <mhildebrand@microsoft.com>

## Breaking changes since 0.53.0 ### Graph search: `DataProvider` contract collapsed into `SearchAccessor` (#1067) `Accessor`, `BuildQueryComputer`, `ExpandBeam`, `SearchExt`, and `AsNeighbor`/`NeighborAccessor` are merged into a single `SearchAccessor` trait. The indexing layer no longer has a notion of element types. - **Upgrade:** Implement `SearchAccessor` instead of the removed traits; use `SearchAccessor::expand_beam` for search. `SearchStrategy`/`InsertStrategy`/`DefaultSearchStrategy`/`DefaultPostProcessor` now carry a lifetime, and the query is passed into `search_accessor` (accessors may now borrow the query). `SearchPostProcess` no longer takes a `QueryComputer` (only requires `HasId`). The blanket `workingset::Fill` impl for `workingset::Map` was removed — implement `Fill` yourself, or use the new synchronous `Map::fill` helper. ### Insert/prune: consolidated into `PruneAccessor` (#1138, follow-up to #1067) Removed `DelegateNeighbor`, `AsNeighbor`, `AsNeighborMut`, `HasElementRef`, `BuildDistanceComputer`, `workingset::Fill`, and `workingset::AsWorkingSet`, folded into a single `PruneAccessor` trait. - **Upgrade:** Implement `PruneAccessor` (provides `neighbors()` for neighbor delegation and `fill()` returning both a `View` and the distance computer). Note `neighbors()` now borrows `&mut self`. ### `VectorId`: removed scalar conversion traits/bounds (#1145, #1133) Dropped `VectorIdTryFrom`, `TryIntoVectorId`, methods `vector_id_try_from`/`try_into_vector_id`, helpers `vecid_from_u32`/`vecid_from_usize`, and `IdConversionError`/`ErrorToVectorId`. Internal IDs no longer need to convert to/from `usize`. - **Upgrade:** Where `usize` conversion is still required (e.g. roaring-treemap keys in `diskann-label-filter`), add an explicit `IntoUsize` bound (now required on `RoaringAttributeStore`, `InlineBetaStrategy`, `QueryBitmapEvaluator`/`BitmapFilter`). `DiskANNIndex::prune_range` now takes `impl IntoIterator<Item = DP::InternalId> + Send` instead of `Range<DP::InternalId>` — construct the iterator for your ID type at the call site. `SimpleNeighborProviderAsync` and `bftree::VectorProvider` are no longer generic over the ID type (fixed to `u32`). ### `DiskIndexReader`: dropped vestigial `VectorType` generic (#1161) - **Upgrade:** Replace `DiskIndexReader::<T>::new(...)` with `DiskIndexReader::new(...)`. ### Filtered search renames (#1149) `MultihopSearch` → `MultihopFilterSearch`; benchmark config phases `MultiHopSearchPhase`/`InlineSearchPhase` → `MultihopFilterSearchPhase`/`InlineFilterSearchPhase`. - **Upgrade:** Update references to the new names. ### `diskann-garnet` FFI: BIN/Q8 quantizers, bumped to 2.0.0 (#1050) Vectors are now stored as `Poly<[u8], AlignOfEight>`; a type-erased `GarnetQuantizer` trait replaces index/provider type parameterization. New FFI: `insert()` returns a success/training-ready flag, plus `build_quant_table()` and `backfill_quant_vectors()` for caller-driven async training/backfill. Accessor renamed to `DynamicAccessor`; the FSM is now lockable and gained `visit_used()`. - **Upgrade:** Garnet consumers must adopt the new 2.0.0 FFI surface (handle the new `insert()` return flag and drive `build_quant_table`/`backfill_quant_vectors`). ## Notable fixes & features (non-breaking) - **Concurrency:** Fixed an ID double-minting race during concurrent insert/delete; delete now removes mapping/attributes before marking the ID free (#1146). Fixed garnet handling of missing quant vectors during `delete()` (#1130). - **Quantization:** Fixed quantizer detection in `train_quantizer()` / `set_element()` (#1140). - **Filtered search:** Added inline filtered search with adaptive `L` (#1131), per the filtered-search RFC (#1128). - **bftree:** Fixed a bug writing the length to the neighbor list (#1150). - **Benchmarks/infra:** Multi-vector MaxSim benchmark with BYOTE factory (#1027); `bf_tree` benchmark infrastructure (#1106); spherical exhaustive benchmark threadpool fix (#1148); right-sized `tiled_reduce` tile buffer (#1123). - `BufferedDistance` accepts `UnalignedSlice`: added a `PreprocessedDistanceFunction<UnalignedSlice<'_, T>>` impl for `BufferedDistance` (#1113).

Magdalen Manohar added 12 commits May 14, 2026 17:56

finish up recall computation patch

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magdalendobson marked this pull request as ready for review June 2, 2026 21:01

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Magdalen Manohar and others added 2 commits June 2, 2026 21:38

missing hyperlink

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Merge branch 'users/magdalen/filtered_search_rfc' of github.com:micro…

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…soft/DiskANN into users/magdalen/filtered_search_rfc

Rename RFC file to PR-number prefix

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Copilot finished work on behalf of magdalendobson June 2, 2026 21:42

magdalendobson changed the title ~~[RFC]~~ [RFC] What filtered search algorithms should DiskANN support? Jun 3, 2026

move benchmarks to wiki page

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arrayka reviewed Jun 3, 2026

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respond to comments

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magdalendobson linked an issue Jun 5, 2026 that may be closed by this pull request

Post evaluation results and RFC with recommendations #1135

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sampathrg reviewed Jun 8, 2026

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fix broken link

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mention more adjacency list fetches for multi-hop

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magdalendobson mentioned this pull request Jun 8, 2026

Inline filtered search with adaptive L #1131

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magdalendobson merged commit a5c745b into main Jun 10, 2026
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magdalendobson deleted the users/magdalen/filtered_search_rfc branch June 10, 2026 14:34

arkrishn94 mentioned this pull request Jun 15, 2026

Bump version to 0.54.0 #1165

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