knowhere-v2.2.0

Release Notes

New Features

• FastScan Integration with FAISS: (#1)

  • Introducing support for FastScan from FAISS. Functionally analogous to SCANN, FastScan utilizes a 4-bit PQ with IVF to enhance the search speed, making it ideal for high-dimensional vector searches.

• New index type IVF_FLAT_CC: (milvus-io/knowhere#824)

  • Introducing new index type IVF_FLAT_CC for growing segment searching.

• Memory-Mapped Support: (milvus-io/knowhere#785 milvus-io/knowhere#1006 milvus-io/knowhere#1015)

  • mmap is now compatible with the FAISS series of indexes and HNSW.

• Extended Metric Support: (milvus-io/knowhere#812)

  • We've added support for the COSINE metric across all float indexes.

• Binary Data Handling: (milvus-io/knowhere#978)

  • HNSW can now process binary data with metric type HAMMING or JACCARD.

• Support prometheus metrics: (milvus-io/knowhere#756)

• GetVectorByIds API: (milvus-io/knowhere#791 milvus-io/knowhere#802 milvus-io/knowhere#805 milvus-io/knowhere#815)

  • This new API facilitates the retrieval of vectors from indexes.

  • Users must first invoke HasRawData prior to GetVectorByIds to confirm the vectors' presence. (milvus-io/knowhere#828)

    Support Matrix for GetVectorByIds

    Indexes	IP	L2	COSINE
    FLAT	Y	Y	Y
    IVF_FLAT	Y	Y	N
    IVF_PQ	N	N	N
    IVF_SQ	N	N	N
    HNSW	Y	Y	Y
    DiskANN	N	Y	Y
    SCANN	Y	Y	Y

Other Changes

• Dependency Management with Conan: (milvus-io/knowhere#728)

  • We've integrated conan to streamline our dependency management.

• Replace Easylogging++ by Glog: (milvus-io/knowhere#766)

• Integration with Folly: (milvus-io/knowhere#788)

  • We've incorporated folly as our preferred third-party standard library.

• Unified RangeSearch Semantics: (milvus-io/knowhere#1016)

  • The RangeSearch functions of Faiss IVF-serials have been updated to be parameter-less for indexes, providing a cohesive semantic experience.

• Enhanced Search Capabilities: (milvus-io/knowhere#794)

  • The search performance for HNSW has been optimized, especially for filtering.

• Thread Management Improvements: (#15)

  • To counteract thread contention, build and search thread pools have been separated. Additionally, Knowhere's thread priority is automatically lowered to prevent disruptions to the primary thread.

• Discontinued Metrics for Binary Indexes: (milvus-io/knowhere#994)

  • Support for metrics such as TANIMOTO, SUBSTRUCTURE, and SUPERSTRUCTURE has been phased out for Binary indexes.

• Discontinued index type ANNOY: (milvus-io/knowhere#796)

  • Support for index type ANNOY has been phased out.

• Improve code coverage: (milvus-io/knowhere#949 milvus-io/knowhere#955 milvus-io/knowhere#958 milvus-io/knowhere#959 milvus-io/knowhere#972)