Struct ColumnPruningContext

pub struct ColumnPruningContext {
    share_required_cols_map: HashMap<PlanNodeId, Vec<Vec<usize>>>,
    share_parent_counter: ShareParentCounter,
    share_cache: HashMap<PlanNodeId, (PlanRef, Vec<usize>)>,
    share_visited: HashSet<PlanNodeId>,
}

Fields

share_required_cols_map: HashMap<PlanNodeId, Vec<Vec<usize>>>

share_required_cols_map is used by the first round of column pruning to keep track of each parent required columns.

share_parent_counter: ShareParentCounter

Used to calculate how many parents the share operator has.

share_cache: HashMap<PlanNodeId, (PlanRef, Vec<usize>)>

Share input cache used by the second round of column pruning. For a DAG plan, use only one round to prune column is not enough, because we need to change the schema of share operator and you don’t know what is the final schema when the first parent try to prune column, so we need a second round to use the information collected by the first round. share_cache maps original share operator plan id to the new share operator and the column changed mapping which is actually the merged required columns calculated at the first round.

share_visited: HashSet<PlanNodeId>

share_visited is used to track whether the share operator is visited, because we need to recursively call the prune_col of the new share operator to trigger the replacement. It is only used at the second round of the column pruning.

Implementations

impl ColumnPruningContext

pub fn new(root: PlanRef) -> Self

pub fn get_parent_num(&self, share: &LogicalShare) -> usize

pub fn add_required_cols( &mut self, plan_node_id: PlanNodeId, required_cols: Vec<usize>, ) -> usize

pub fn take_required_cols( &mut self, plan_node_id: PlanNodeId, ) -> Option<Vec<Vec<usize>>>

pub fn add_share_cache( &mut self, plan_node_id: PlanNodeId, new_share: PlanRef, merged_required_columns: Vec<usize>, )

pub fn get_share_cache( &self, plan_node_id: PlanNodeId, ) -> Option<(PlanRef, Vec<usize>)>

pub fn need_second_round(&self) -> bool

pub fn visit_share_at_second_round(&mut self, plan_node_id: PlanNodeId) -> bool

Trait Implementations

impl Clone for ColumnPruningContext

fn clone(&self) -> ColumnPruningContext

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ColumnPruningContext

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

Formats the value using the given formatter.