Package org.apache.flink.table.runtime.operators.window.slicing

Class SliceAssigners.SlicedSharedSliceAssigner

java.lang.Object

org.apache.flink.table.runtime.operators.window.slicing.SliceAssigners.SlicedSharedSliceAssigner

All Implemented Interfaces:

Serializable, SliceAssigner, SliceSharedAssigner

Enclosing class:

SliceAssigners

public static final class SliceAssigners.SlicedSharedSliceAssigner
extends Object
implements SliceSharedAssigner

The SliceAssigner for elements have been attached slice end timestamp, and the slices are shared.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.table.runtime.operators.window.slicing.SliceSharedAssigner

SliceSharedAssigner.MergeCallback

Constructor Summary

Constructors

Constructor	Description
SlicedSharedSliceAssigner(int sliceEndIndex, SliceSharedAssigner innerAssigner)

Method Summary

Modifier and Type	Method	Description
long	getLastWindowEnd(long sliceEnd)	Returns the last window which the slice belongs to.
void	mergeSlices(long sliceEnd, SliceSharedAssigner.MergeCallback callback)	Determines which slices (if any) should be merged.
Optional<Long>	nextTriggerWindow(long windowEnd, java.util.function.Supplier<Boolean> isWindowEmpty)	Returns the optional end timestamp of next window which should be triggered.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.flink.table.runtime.operators.window.slicing.SliceAssigner

assignSliceEnd, expiredSlices, getSliceEndInterval, getWindowStart, isEventTime

Constructor Detail

SlicedSharedSliceAssigner

public SlicedSharedSliceAssigner(int sliceEndIndex,
                                 SliceSharedAssigner innerAssigner)

Method Detail

mergeSlices

public void mergeSlices(long sliceEnd,
                        SliceSharedAssigner.MergeCallback callback)
                 throws Exception

Description copied from interface: SliceSharedAssigner

Determines which slices (if any) should be merged.

Specified by:

mergeSlices in interface SliceSharedAssigner

Parameters:

sliceEnd - the triggered slice, identified by end timestamp

callback - a callback that can be invoked to signal which slices should be merged.

Throws:

Exception

nextTriggerWindow

public Optional<Long> nextTriggerWindow(long windowEnd,
                                        java.util.function.Supplier<Boolean> isWindowEmpty)

Description copied from interface: SliceSharedAssigner

Returns the optional end timestamp of next window which should be triggered. Empty if no following window to trigger for now.

The purpose of this method is avoid register too many timers for each hopping and cumulative slice, e.g. HOP(1day, 10s) needs register 8640 timers for every slice. In order to improve this, we only register one timer for the next window. For hopping windows we don't register next window if current window is empty (i.e. no records in current window). That means we will have one more unnecessary window triggered for hopping windows if no elements arrives for a key for a long time. We will skip to emit window result for the triggered empty window, see SliceSharedWindowAggProcessor.fireWindow(Long).

Specified by:

nextTriggerWindow in interface SliceSharedAssigner

Parameters:

windowEnd - the current triggered window, identified by end timestamp

isWindowEmpty - a supplier that can be invoked to get whether the triggered window is empty (i.e. no records in the window).

getLastWindowEnd

public long getLastWindowEnd(long sliceEnd)

Description copied from interface: SliceAssigner

Returns the last window which the slice belongs to. The window and slices are both identified by the end timestamp.

Specified by:

getLastWindowEnd in interface SliceAssigner