Struct DataFusionEngine 

pub struct DataFusionEngine { /* private fields */ }

An engine instance using DataFusion for catalogue management and queries.

Implementations

impl DataFusionEngine

pub fn new(ctx: SessionContext) -> Self

Creates a new engine instance using the given DataFusion execution context.

Examples found in repository

examples/datafusion.rs (line 51)

async fn new_engine() -> DataFusionEngine {
	let ctx = SessionContext::new_with_config(
		SessionConfig::new()
			.with_information_schema(true)
			.with_create_default_catalog_and_schema(false),
	);

	let mem_catalog = Arc::new(MemoryCatalogProvider::new());
	mem_catalog
		.register_schema("public", Arc::new(MemorySchemaProvider::new()))
		.expect("failed to register schema");

	ctx.register_catalog("datafusion", Arc::new(Catalog::new(mem_catalog)));

	ctx.register_csv(
		"test_100_4buckets",
		"convergence-arrow/data/100_4buckets.csv",
		CsvReadOptions::new(),
	)
	.await
	.expect("failed to register csv");

	ctx.register_udf(create_udf(
		"pg_backend_pid",
		vec![],
		DataType::Int32,
		Volatility::Stable,
		Arc::new(|_| Ok(ColumnarValue::Scalar(ScalarValue::Int32(Some(0))))),
	));

	ctx.register_udf(create_udf(
		"current_schema",
		vec![],
		DataType::Utf8,
		Volatility::Stable,
		Arc::new(|_| Ok(ColumnarValue::Scalar(ScalarValue::Utf8(Some("public".to_owned()))))),
	));

	DataFusionEngine::new(ctx)
}

Trait Implementations

impl Engine for DataFusionEngine

type PortalType = DataFusionPortal

The Portal implementation used by Engine::create_portal.

fn prepare<'life0, 'life1, 'async_trait>( &'life0 mut self, statement: &'life1 Statement, ) -> Pin<Box<dyn Future<Output = Result<Vec<FieldDescription>, ErrorResponse>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Prepares a statement, returning a vector of field descriptions for the final statement result.

fn create_portal<'life0, 'life1, 'async_trait>( &'life0 mut self, statement: &'life1 Statement, ) -> Pin<Box<dyn Future<Output = Result<Self::PortalType, ErrorResponse>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Creates a new portal for the given statement.