Module aggr_wrapper

Wrapper for making aggregate functions out of state/merge functions of original aggregate functions.

i.e. for a aggregate function foo, we will have a state function foo_state and a merge function foo_merge.

foo_state’s input args is the same as foo’s, and its output is a state object. Note that foo_state might have multiple output columns, so it’s a struct array that each output column is a struct field. foo_merge’s input arg is the same as foo_state’s output, and its output is the same as foo’s input.

Structs

MergeAccum

The merge accumulator, which modify update_batch’s behavior to accept one struct array which include the state fields of original aggregate function, and merge said states into original accumulator the output is the same as original aggregate function

MergeWrapper

TODO(discord9): mark this function as non-ser/de able

StateAccum

The wrapper’s input is the same as the original aggregate function’s input, and the output is the state function’s output.

StateMergeHelper

A wrapper to make an aggregate function out of the state and merge functions of the original aggregate function. It contains the original aggregate function, the state functions, and the merge function.

StateWrapper

Wrapper to make an aggregate function out of a state function.

StepAggrPlan

A struct to hold the two aggregate plans, one for the state function(lower) and one for the merge function(upper).

Functions

aggr_merge_func_name

Returns the name of the merge function for the given aggregate function name. The merge function is used to merge the states of the state functions. The merge function’s name is in the format `__<aggr_name>_merge

aggr_state_func_name

Returns the name of the state function for the given aggregate function name. The state function is used to compute the state of the aggregate function. The state function’s name is in the format `__<aggr_name>_state

get_aggr_func