org.apache.flink.table.runtime.generated

Interface AggsHandleFunction

All Superinterfaces:

AggsHandleFunctionBase, Function, Serializable

public interface AggsHandleFunction
extends AggsHandleFunctionBase

The base class for handling aggregate functions.

It is code generated to handle all AggregateFunctions together in an aggregation.

It is the entry point for aggregate operators to operate all AggregateFunctions.

Method Summary

Modifier and Type	Method and Description
RowData	getValue() Gets the result of the aggregation from the current accumulators.
void	setWindowSize(int windowSize) Set window size for the aggregate function.

Methods inherited from interface org.apache.flink.table.runtime.generated.AggsHandleFunctionBase

accumulate, cleanup, close, createAccumulators, getAccumulators, merge, open, resetAccumulators, retract, setAccumulators

Method Detail

getValue

RowData getValue()
          throws Exception

Gets the result of the aggregation from the current accumulators.

Returns:

the final result (saved in a row) of the current accumulators.

Throws:

Exception

setWindowSize

void setWindowSize(int windowSize)

Set window size for the aggregate function. It's used in batch scenario to set the total rows of the current window frame. More information for window frame: https://docs.oracle.com/cd/E17952_01/mysql-8.0-en/window-functions-frames.html

We may need to set the value for some window functions may require the total rows of current window frame to do calculation. For example, the function PERCENT_RANK need to know the window's size, and the SQL looks like: SELECT PERCENT_RANK() OVER ([ partition_by_clause] order_by_clause).