cron (Window)

This window outputs the arriving events as and when they arrive, and resets (expires) the window periodically based on the given cron expression.

Syntax

cron(<STRING> cron.expression)

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
cron.expression	The cron expression that resets the window.		STRING	No	No

Example 1

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

@info(name = 'query1')
insert into OutputStream
select symbol, sum(price) as totalPrice
from InputEventStream#cron('*/5 * * * * ?');

This let the totalPrice to gradually increase and resets to zero as a batch every 5 seconds.

Example 2

CREATE STREAM StockEventStream (symbol string, price float, volume int)
CREATE WINDOW StockEventWindow (symbol string, price float, volume int) cron('*/5 * * * * ?');

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

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

The defined window enables the totalPrice to gradually increase and resets to zero as a batch every 5 seconds.