Enum RowRef 

pub enum RowRef {
    Owned(Row),
    Composite(CompositeRow),
    DirectBuildComposite(DirectBuildCompositeRow),
}

A row reference that can be borrowed, owned, or composite.

This enum allows operators to return rows without always cloning:

• Borrowed: Reference to an existing row (zero-copy)
• Owned: An owned row (when materialization is needed)
• Composite: Virtual row combining left and right join sides

Performance

The key optimization is that Composite allows hash joins to return combined rows without actually copying values from both sides. Values are only copied when the final result is materialized.

Variants

Owned(Row)

Owned row - the row data is owned by this RowRef.

Composite(CompositeRow)

Composite row - combines two rows without copying. Used by join operators to avoid materializing combined rows.

DirectBuildComposite(DirectBuildCompositeRow)

Direct build composite - combines owned probe row with Arc-referenced build rows. OPTIMIZATION: Avoids Arc allocation for probe row (saves 1 allocation per match). Used for hash joins where build rows are shared via Arc.

Implementations

impl RowRef

pub fn owned(row: Row) -> Self

Create an owned RowRef from a Row.

pub fn composite(left: Row, right: Row) -> Self

Create a composite RowRef from left and right rows.

pub fn len(&self) -> usize

Get the number of columns in this row.

pub fn is_empty(&self) -> bool

Check if this row is empty.

pub fn get(&self, idx: usize) -> Option<&Value>

Get a value by index without cloning.

pub fn into_owned(self) -> Row

Convert to an owned Row.

For Owned, this is a no-op move. For Composite and DirectBuildComposite, this materializes the combined row.

pub fn to_owned(&self) -> Row

Clone to an owned Row.

Use into_owned() when possible to avoid cloning.

pub fn as_row(&self) -> Option<&Row>

Get a reference to the underlying Row if this is Owned.

pub fn direct_build_composite( probe: Row, build_rows: CompactArc<Vec<Row>>, build_idx: usize, probe_is_left: bool, ) -> Self

Create a direct-build composite RowRef.

OPTIMIZATION: Avoids Arc allocation for probe row. Use this for 1:1 joins where probe row is owned and not shared.

Trait Implementations

impl Debug for RowRef

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.