Enum RowRef 

pub enum RowRef {
    Owned(Row),
    Composite(CompositeRow),
    DirectBuildComposite(DirectBuildCompositeRow),
    Shared(SharedRow),
    Projected(ProjectedRow),
    Deferred(DeferredRow),
}

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.

Shared(SharedRow)

One row in an immutable shared build batch.

This lets a projected JOIN output retain the build row by Arc + index instead of cloning every value from that row.

Projected(ProjectedRow)

Projected virtual row over an existing outer row and one joined row.

Unlike an owned projected Row, this keeps the selected slots virtual across subsequent JOIN edges. Values are copied only when the final result consumer requests an owned row.

Deferred(DeferredRow)

Deferred row carried through an internal QueryResult boundary.

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.

pub fn shared(rows: CompactArc<Vec<Row>>, row_idx: usize) -> Self

Reference one row in an immutable shared batch.

pub fn projected( left: RowRef, right: RowRef, columns: CompactArc<[ColumnSource]>, ) -> Self

Create a deferred projected row for a JOIN output.

pub fn deferred(row: DeferredRow) -> Self

Restore a compact row received from an internal QueryResult boundary.

pub fn into_deferred(self) -> DeferredRow

Convert into the portable representation used between recursive JOINs.

pub fn is_deferred(&self) -> bool

Whether this row still carries a deferred JOIN representation.

pub fn estimated_retained_bytes(&self) -> usize

Conservative size of the request-local row graph retained by this handle. Arc-backed immutable batches are owned and charged elsewhere; this method accounts only for the handle/graph added by a pull batch.

Trait Implementations

impl Clone for RowRef

fn clone(&self) -> RowRef

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RowRef

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

Formats the value using the given formatter.