Implementation:Lance format Lance Java IndexType

Knowledge Sources	Lance
Domains	Java_SDK, Indexing
Last Updated	2026-02-08 19:33 GMT

Overview

Description

IndexType is a Java enum in the org.lance.index package that enumerates all supported index types in the Lance format. Each enum constant has an associated integer value matching the Rust representation. The enum covers scalar index types (values 0-9), including SCALAR, BTREE, BITMAP, LABEL_LIST, INVERTED, NGRAM, FRAGMENT_REUSE, MEM_WAL, ZONEMAP, and BLOOM_FILTER, as well as vector index types (values 100+), including VECTOR, IVF_FLAT, IVF_SQ, IVF_PQ, IVF_HNSW_SQ, IVF_HNSW_PQ, and IVF_HNSW_FLAT.

Usage

IndexType is used throughout the Java SDK to classify and select the type of index to create or query. It appears as a required parameter in IndexOptions and as a metadata field in Index.

Code Reference

Source Location

java/src/main/java/org/lance/index/IndexType.java

Signature

public enum IndexType {
    SCALAR(0),
    BTREE(1),
    BITMAP(2),
    LABEL_LIST(3),
    INVERTED(4),
    NGRAM(5),
    FRAGMENT_REUSE(6),
    MEM_WAL(7),
    ZONEMAP(8),
    BLOOM_FILTER(9),
    VECTOR(100),
    IVF_FLAT(101),
    IVF_SQ(102),
    IVF_PQ(103),
    IVF_HNSW_SQ(104),
    IVF_HNSW_PQ(105),
    IVF_HNSW_FLAT(106);

    public int getValue();
}

Import

import org.lance.index.IndexType;

I/O Contract

Enum Values

Constant	Integer Value	Category	Description
SCALAR	0	Scalar	Generic scalar index
BTREE	1	Scalar	B-Tree index for ordered scalar lookups
BITMAP	2	Scalar	Bitmap index for low-cardinality columns
LABEL_LIST	3	Scalar	Label list index for multi-label columns
INVERTED	4	Scalar	Inverted index for full-text search
NGRAM	5	Scalar	N-gram index for substring matching
FRAGMENT_REUSE	6	Scalar	Fragment reuse index
MEM_WAL	7	Scalar	Memory WAL index
ZONEMAP	8	Scalar	Zone map index for range filtering
BLOOM_FILTER	9	Scalar	Bloom filter index for membership queries
VECTOR	100	Vector	Generic vector index
IVF_FLAT	101	Vector	IVF with flat (uncompressed) storage
IVF_SQ	102	Vector	IVF with scalar quantization
IVF_PQ	103	Vector	IVF with product quantization
IVF_HNSW_SQ	104	Vector	IVF + HNSW graph with scalar quantization
IVF_HNSW_PQ	105	Vector	IVF + HNSW graph with product quantization
IVF_HNSW_FLAT	106	Vector	IVF + HNSW graph with flat storage

Usage Examples

import org.lance.index.IndexType;

// Check the integer value of an index type
IndexType type = IndexType.IVF_PQ;
System.out.println("IVF_PQ value: " + type.getValue()); // 103

// Use in index creation
IndexOptions options = IndexOptions.builder(
    Arrays.asList("embedding"), IndexType.IVF_HNSW_SQ, params
).build();

// Compare index types from metadata
Index idx = ...;
if (idx.indexType() == IndexType.BTREE) {
    System.out.println("This is a B-Tree index");
}

Related Pages

• Index - Uses IndexType as a metadata field
• IndexOptions - Requires IndexType to specify which index to create
• DistanceType - Distance metric enum used alongside vector index types