TUMBLING_EXTERNAL_TIME

This is a batch (tumbling) time window that is determined based on an external time, i.e., time stamps that are specified via an attribute in the events. It holds the latest unique events that arrived during the last window time period.

The unique events are determined based on the value for a specified unique key parameter. When a new event arrives within the time window with a value for the unique key parameter that is the same as that of an existing event in the window, the existing event expires and it is replaced by the new event.

Syntax

    WINDOW UNIQUE:TUMBLING_EXTERNAL_TIME(<INT|LONG|FLOAT|BOOL|DOUBLE|STRING> unique.key, <LONG> time.stamp, <INT|LONG> window.time)
    WINDOW UNIQUE:TUMBLING_EXTERNAL_TIME(<INT|LONG|FLOAT|BOOL|DOUBLE|STRING> unique.key, <LONG> time.stamp, <INT|LONG> window.time, <INT> start.time)
    WINDOW UNIQUE:TUMBLING_EXTERNAL_TIME(<INT|LONG|FLOAT|BOOL|DOUBLE|STRING> unique.key, <LONG> time.stamp, <INT|LONG> window.time, <INT> start.time, <INT|LONG> time.out)
    WINDOW UNIQUE:TUMBLING_EXTERNAL_TIME(<INT|LONG|FLOAT|BOOL|DOUBLE|STRING> unique.key, <LONG> time.stamp, <INT|LONG> window.time, <INT> start.time, <INT|LONG> time.out, <BOOL> replace.time.stamp.with.batch.end.time)

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
unique.key	The attribute that should be checked for uniqueness.		INT LONG FLOAT BOOL DOUBLE STRING	No	Yes
time.stamp	The time which the window determines as the current time and acts upon. The value of this parameter should be monotonically increasing.		LONG	No	Yes
window.time	The sliding time period for which the window should hold events.		INT LONG	No	No
start.time	This specifies an offset in milliseconds in order to start the window at a time different to the standard time.	Timestamp of first event	INT	Yes	No
time.out	Time to wait for arrival of a new event, before flushing and returning the output for events belonging to a specific batch.	The system waits till an event from the next batch arrives to flush the current batch	INT LONG	Yes	No
replace.time.stamp.with.batch.end.time	Replaces the timestamp value with the corresponding batch end time stamp.	false	BOOL	Yes	No

Example 1

    CREATE STREAM LoginEvents (timestamp long, ip string);

    INSERT INTO UniqueIps 
    SELECT timestamp, ip, count() AS total
    FROM LoginEvents WINDOW UNIQUE:TUMBLING_EXTERNAL_TIME(ip, timestamp, 1 sec, 0, 2 sec);

In this query, the window holds the latest unique events that arrive from the LoginEvent stream during each second. The latest events are determined based on the external time stamp.

At a given time, all the events held in the window have unique values for the ip and monotonically increasing values for timestamp attributes. The events in the window are inserted into the UniqueIps output stream. The system waits two seconds for the arrival of a new event before flushing the current batch.