lengthBatch (Window)

A batch (tumbling) length window that holds and process a number of events as specified in the window.length.

Syntax

lengthBatch(<INT> window.length)
lengthBatch(<INT> window.length, <BOOL> stream.current.event)

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
window.length	The number of events the window should tumble.		INT	No	No
stream.current.event	Let the window stream the current events out as and when they arrive to the window while expiring them in batches.	false	BOOL	Yes	No

Example 1

CREATE STREAM InputEventStream (symbol string, price float, volume int);

@info(name = 'query1')
insert into OutputStream
select symbol, sum(price) as price
from InputEventStream#lengthBatch(10);

This collect and process 10 events as a batch and output them.

Example 2

CREATE STREAM InputEventStream (symbol string, price float, volume int);

@info(name = 'query1')
insert into OutputStream
select symbol, sum(price) as sumPrice
from InputEventStream#lengthBatch(10, true);

This window sends the arriving events directly to the output letting the sumPrice to increase gradually, after every 10 events it clears the window as a batch and resets the sumPrice to zero.

Example 3

CREATE STREAM InputEventStream (symbol string, price float, volume int);
CREATE WINDOW StockEventWindow (symbol string, price float, volume int) lengthBatch(10) output all events;

@info(name = 'query0')
insert into StockEventWindow
from InputEventStream;

@info(name = 'query1')
insert all events into OutputStream 
select symbol, sum(price) as price
from StockEventWindow;

This uses a defined window to process 10 events as a batch and output all events.