feat: add fragment enumeration and fragment-scoped scanning APIs#3
Merged
jja725 merged 3 commits intolance-format:mainfrom Mar 26, 2026
Merged
feat: add fragment enumeration and fragment-scoped scanning APIs#3jja725 merged 3 commits intolance-format:mainfrom
jja725 merged 3 commits intolance-format:mainfrom
Conversation
lance-encoding's build script requires protoc. Install it via apt-get on Linux and brew on macOS. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Add three new C API functions for fragment-level access: - lance_dataset_fragment_count() — returns number of fragments - lance_dataset_fragment_ids() — fills caller-allocated array with fragment IDs - lance_scanner_set_fragment_ids() — restricts scan to specific fragments This enables split-based parallelism for query engines like Velox, where each worker scans a subset of fragments. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Summary
Add three new C API functions for fragment-level access, enabling split-based parallelism for query engines like Velox.
lance_dataset_fragment_count()— returns number of fragments in the datasetlance_dataset_fragment_ids()— fills caller-allocated array with fragment IDslance_scanner_set_fragment_ids()— restricts scan to specific fragment IDsMotivation
Query engines like Velox distribute work across workers by assigning each worker a subset of fragments (splits). Without fragment-level APIs, the connector cannot partition the scan work.
Changes
src/dataset.rslance_dataset_fragment_count,lance_dataset_fragment_idssrc/scanner.rslance_scanner_set_fragment_ids,fragment_idsfield, fragment filtering inmaterialize_streamandbuild_scannerinclude/lance.hinclude/lance.hppDataset::fragment_count(),Dataset::fragment_ids(),Scanner::fragment_ids())tests/c_api_test.rstest_fragment_count,test_fragment_ids,test_scanner_with_fragment_idsTest plan
cargo test— 40 tests pass (3 new fragment tests)cargo clippy --all-targets -- -D warnings— cleancargo fmt -- --check— clean🤖 Generated with Claude Code