Struct ProjectionPlan

pub struct ProjectionPlan {
    pub physical_projection: Projection,
    pub desires_row_id: bool,
    pub desires_row_addr: bool,
    pub requested_output_expr: Option<Vec<(Expr, String)>>,
    /* private fields */
}

Fields

physical_projection: Projection

The physical schema that must be loaded from the dataset

desires_row_id: bool

True if the user wants the row id in the final output

Note: this is related, but slightly different, to physical_projection.with_row_id which only tracks if the row id is needed.

desires_row_id implies with_row_id is true However, it is possible to have desires_row_id=false and with_row_id=true (e.g. when the row id is needed to perform a late materialization take)

desires_row_addr: bool

True if the user wants the row address in the final output

Note: this is related, but slightly different, to physical_projection.with_row_addr which only tracks if the row address is needed.

desires_row_addr implies with_row_addr is true However, it is possible to have deisres_row_addr=false and with_row_addr=true (e.g. during a count query)

requested_output_expr: Option<Vec<(Expr, String)>>

If present, expressions that represent the output columns. These expressions run on the output of the physical projection.

If not present, the output is the physical projection.

Note: this doesn’t include _distance, and _rowid

Implementations

impl ProjectionPlan

pub fn new(base: Arc<dyn Projectable>) -> Self

Create a new projection plan which projects all columns and does not include any expressions

pub fn project_from_expressions( &mut self, columns: &[(impl AsRef<str>, impl AsRef<str>)], ) -> Result<()>

Set the projection from SQL expressions

pub fn project_from_schema(&mut self, projection: &Schema)

Set the projection from a schema

This plan will have no complex expressions

pub fn to_physical_exprs( &self, current_schema: &ArrowSchema, ) -> Result<Vec<(Arc<dyn PhysicalExpr>, String)>>

Convert the projection to a list of physical expressions

This is used to apply the final projection (including dynamic expressions) to the data.

pub fn include_row_id(&mut self)

Include the row id in the output

pub fn include_row_addr(&mut self)

Include the row address in the output

pub fn has_output_cols(&self) -> bool

Check if the projection has any output columns

This doesn’t mean there is a physical projection. For example, we may someday support something like SELECT 1 AS foo which would have an output column (foo) but no physical projection

pub fn output_schema(&self) -> Result<ArrowSchema>

pub async fn project_batch(&self, batch: RecordBatch) -> Result<RecordBatch>

Trait Implementations

impl Clone for ProjectionPlan

fn clone(&self) -> ProjectionPlan

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ProjectionPlan

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

Formats the value using the given formatter.