Struct RowGroupFrontier 

struct RowGroupFrontier {
    parquet_metadata: Arc<ParquetMetaData>,
    row_groups: VecDeque<usize>,
    selection: Option<RowSelection>,
    budget: RowBudget,
    has_predicates: bool,
}

Fields

parquet_metadata: Arc<ParquetMetaData>

Metadata used to resolve row counts for queued row groups.

row_groups: VecDeque<usize>

Row group indices not yet handed to the builder.

selection: Option<RowSelection>

Cross-row-group cursor for the optional global row selection.

budget: RowBudget

Offset/limit budget before the next readable row group is planned.

has_predicates: bool

If predicates are present, row groups with selected rows must be read so the predicate can decide whether they are actually needed.

Implementations

impl RowGroupFrontier

fn new( parquet_metadata: Arc<ParquetMetaData>, row_groups: Vec<usize>, selection: Option<RowSelection>, budget: RowBudget, has_predicates: bool, ) -> Self

fn row_group_num_rows( &self, row_group_idx: usize, ) -> Result<usize, ParquetError>

fn update_budget_after_row_group(&mut self, budget: RowBudget)

fn peek_next_row_group(&self) -> Result<Option<usize>, ParquetError>

Peek at the next row-group index Self::next_readable_row_group would hand out, without mutating any state. Returns None if every remaining row group would be skipped under the current selection/budget, or if the queue is empty.

Runs the real Self::next_readable_row_group advance logic on a throwaway clone of the frontier, so peek can never drift from the read path. The clone copies the queued row-group indices and optional row-selection (a Vec<RowSelector>); see RemainingRowGroups::peek_next_row_group.

fn clear_remaining(&mut self)

fn plan_selected_row_group( &self, next_row_group: NextRowGroup, selected_rows: usize, ) -> QueuedRowGroupDecision

Plan whether a selected row group should be read or skipped.

Selection-only skips are handled before this method is called. This method applies the remaining offset/limit budget and predicate conservatism.

fn next_readable_row_group( &mut self, ) -> Result<Option<NextRowGroup>, ParquetError>

Advance queued row groups until one should be handed to the builder.

Trait Implementations

impl Clone for RowGroupFrontier

fn clone(&self) -> RowGroupFrontier

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RowGroupFrontier

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

Formats the value using the given formatter.