Module windows

Physical expressions for window functions

Structs

BoundedWindowAggExec

Window execution plan

PlainAggregateWindowExpr

A window expr that takes the form of an aggregate function.

StandardWindowExpr

A window expr that takes the form of a StandardWindowFunctionExpr.

WindowAggExec

Window execution plan

WindowUDFExpr

Implements StandardWindowFunctionExpr for WindowUDF

Traits

WindowExpr

Common trait for window function implementations

Functions

create_udwf_window_expr

Creates a StandardWindowFunctionExpr suitable for a user defined window function

create_window_expr

Create a physical expression for window function

get_best_fitting_window

Constructs the best-fitting windowing operator (a WindowAggExec or a BoundedWindowExec) for the given input according to the specifications of window_exprs and physical_partition_keys. Here, best-fitting means not requiring additional sorting and/or partitioning for the given input.

get_ordered_partition_by_indices

This function calculates the indices such that when partition by expressions reordered with the indices resulting expressions define a preset for existing ordering. For instance, if input is ordered by a, b, c and PARTITION BY b, a is used, this vector will be [1, 0]. It means that when we iterate b, a columns with the order [1, 0] resulting vector (a, b) is a preset of the existing ordering (a, b, c).

get_window_mode

Compares physical ordering (output ordering of the input operator) with partitionby_exprs and orderby_keys to decide whether existing ordering is sufficient to run the current window operator.

schema_add_window_field

Build field from window function and add it into schema