Crate lance_csr 

Lance Graph Query Engine

This crate provides graph query capabilities for Lance datasets using Cypher syntax. It interprets Lance datasets as property graphs and translates Cypher queries into DataFusion SQL queries for execution.

Features

• Cypher query parsing and AST representation
• Graph pattern matching on columnar data
• Property graph interpretation of Lance datasets
• Translation to optimized SQL via DataFusion
• Support for nodes, relationships, and properties
• A CSR (compressed sparse row) adjacency index for multi-hop traversal

Example

CypherEngine registers datasets once, optionally builds the CSR, and serves many queries. See engine for the full API and examples/embedded_query.rs for a runnable program.

use std::collections::HashMap;
use lance_csr::{CypherEngine, EngineSource, GraphConfig, Result};

let config = GraphConfig::builder()
    .node_table("Person", "person_id")
    .rel_table("KNOWS", "Person", "Person", "src_person_id", "dst_person_id")
    .build()?;
let sources = HashMap::from([
    ("Person".to_string(), EngineSource::open_lance("person.lance", None, HashMap::new()).await?),
    ("KNOWS".to_string(), EngineSource::open_lance("knows.lance", None, HashMap::new()).await?),
]);
let engine = CypherEngine::new(config, sources, true).await?;
let batch = engine
    .execute("MATCH (p:Person) WHERE p.age > 30 RETURN p.name", HashMap::new())
    .await?;

Re-exports

pub use config::GraphConfig;

pub use config::NodeMapping;

pub use config::RelationshipMapping;

pub use csr_index::CsrIndex;

pub use csr_index::CsrIndexBuilder;

pub use engine::CypherEngine;

pub use engine::EngineSource;

pub use error::GraphError;

pub use error::Result;

pub use lance_vector_search::VectorSearch;

pub use query::CypherQuery;

pub use query::ExecutionStrategy;

pub use query::SqlDialect;

pub use sql_query::SqlQuery;

Modules

ast

Abstract Syntax Tree for Cypher queries

case_insensitive

Case-insensitive string utilities

config

Graph configuration for mapping Lance datasets to property graphs

csr_expand

Experimental CSR-backed single-hop expansion.

csr_index

CSR (Compressed Sparse Row) adjacency index for native graph traversal

datafusion_planner

DataFusion-based physical planner for graph queries

engine

A Cypher engine that registers its datasets once and serves many queries.

error

Error types for the Lance graph query engine

key_statistics

Distinct-count statistics for join-key columns, so DataFusion sizes joins correctly.

lance_vector_search

Lance Vector Search API for lance-csr

logical_plan

Logical planning for graph queries

parameter_substitution

parser

Cypher query parser

query

High-level Cypher query interface for Lance datasets

semantic

Semantic analysis for graph queries

shortest_path

shortestPath / allShortestPaths as a breadth-first search over the adjacency.

spark_dialect

Spark SQL dialect for the DataFusion unparser.

sql_query

Direct SQL query interface for Lance datasets

Structs

DirNamespace

A namespace that resolves table names relative to a base directory or URI.

InMemoryCatalog

A simple in-memory catalog useful for tests and bootstrap wiring.

SimpleTableSource

A trivial logical table source with a fixed schema.

Constants

MAX_VARIABLE_LENGTH_HOPS

Maximum allowed hops for variable-length relationship expansion (e.g., *1..N)

Traits

GraphSourceCatalog

A minimal catalog to resolve node labels and relationship types to logical table sources.