Apache Flink - time between events
I am starting to experiment with Apache Flink and have achieved some very basic stuff. Now am I looking forward to finding out the time difference between consecutive elements.
My idea was to use countWindowAll(2) on a stream so that I could evaluate windows with 2 consecutive events. However, I don't understand how I can get access to the timestamps of the 2 events in the window to emit / map this into time difference.
Does someone have a good reference or even some example code for what I am trying to achieve ?
Lars
apache events time streaming apache-flink
asked Nov 16 '18 at 21:41
LarsLars
1
|
show 1 more comment
I am starting to experiment with Apache Flink and have achieved some very basic stuff. Now am I looking forward to finding out the time difference between consecutive elements.
My idea was to use countWindowAll(2) on a stream so that I could evaluate windows with 2 consecutive events. However, I don't understand how I can get access to the timestamps of the 2 events in the window to emit / map this into time difference.
Does someone have a good reference or even some example code for what I am trying to achieve ?
Lars
apache events time streaming apache-flink
asked Nov 16 '18 at 21:41
LarsLars
1
Do your events have event-time timestamps that you want to compare, or are you wanting to use the CPU clock to measure the interval between processing one event and the next?
– David Anderson
Nov 17 '18 at 9:45
I intend to use event-time timestamps. So far, I am experimenting with the Twitter stream to gather some experience - do the tweet events have event timestamps ?
– Lars
Nov 18 '18 at 20:49
Make a window with size 2 and apply the function to get the difference, something looks like this:text.flatMap(_.toLowerCase.split("\W+")).map((_, System.currentTimeMillis())).countWindowAll(2).apply[Long]((_, iter, c) => c.collect(iter.last._2 - iter.head._2)).print()
– David
Nov 19 '18 at 2:32
Keep in mind that most applications with event-time timestamps end up processing events that are out-of-order, in which case comparing the timestamps on consecutive events may not be very meaningful.
– David Anderson
Nov 19 '18 at 8:09
BTW, the WikipediaEditEvent objects used in ci.apache.org/projects/flink/flink-docs-release-1.6/quickstart/… do have timestamps.
– David Anderson
Nov 19 '18 at 8:13
|
show 1 more comment
I am starting to experiment with Apache Flink and have achieved some very basic stuff. Now am I looking forward to finding out the time difference between consecutive elements.
My idea was to use countWindowAll(2) on a stream so that I could evaluate windows with 2 consecutive events. However, I don't understand how I can get access to the timestamps of the 2 events in the window to emit / map this into time difference.
Does someone have a good reference or even some example code for what I am trying to achieve ?
Lars
apache events time streaming apache-flink
asked Nov 16 '18 at 21:41
LarsLars
1
I am starting to experiment with Apache Flink and have achieved some very basic stuff. Now am I looking forward to finding out the time difference between consecutive elements.
My idea was to use countWindowAll(2) on a stream so that I could evaluate windows with 2 consecutive events. However, I don't understand how I can get access to the timestamps of the 2 events in the window to emit / map this into time difference.
Does someone have a good reference or even some example code for what I am trying to achieve ?
Lars
apache events time streaming apache-flink
apache events time streaming apache-flink
asked Nov 16 '18 at 21:41
LarsLars
1
asked Nov 16 '18 at 21:41
LarsLars
1
asked Nov 16 '18 at 21:41
LarsLars
1
asked Nov 16 '18 at 21:41
LarsLars
1
asked Nov 16 '18 at 21:41
LarsLars
1
1
Do your events have event-time timestamps that you want to compare, or are you wanting to use the CPU clock to measure the interval between processing one event and the next?
– David Anderson
Nov 17 '18 at 9:45
I intend to use event-time timestamps. So far, I am experimenting with the Twitter stream to gather some experience - do the tweet events have event timestamps ?
– Lars
Nov 18 '18 at 20:49
Make a window with size 2 and apply the function to get the difference, something looks like this:text.flatMap(_.toLowerCase.split("\W+")).map((_, System.currentTimeMillis())).countWindowAll(2).apply[Long]((_, iter, c) => c.collect(iter.last._2 - iter.head._2)).print()
– David
Nov 19 '18 at 2:32
Keep in mind that most applications with event-time timestamps end up processing events that are out-of-order, in which case comparing the timestamps on consecutive events may not be very meaningful.
– David Anderson
Nov 19 '18 at 8:09
BTW, the WikipediaEditEvent objects used in ci.apache.org/projects/flink/flink-docs-release-1.6/quickstart/… do have timestamps.
– David Anderson
Nov 19 '18 at 8:13
|
show 1 more comment
Do your events have event-time timestamps that you want to compare, or are you wanting to use the CPU clock to measure the interval between processing one event and the next?
– David Anderson
Nov 17 '18 at 9:45
I intend to use event-time timestamps. So far, I am experimenting with the Twitter stream to gather some experience - do the tweet events have event timestamps ?
– Lars
Nov 18 '18 at 20:49
Make a window with size 2 and apply the function to get the difference, something looks like this:text.flatMap(_.toLowerCase.split("\W+")).map((_, System.currentTimeMillis())).countWindowAll(2).apply[Long]((_, iter, c) => c.collect(iter.last._2 - iter.head._2)).print()
– David
Nov 19 '18 at 2:32
Keep in mind that most applications with event-time timestamps end up processing events that are out-of-order, in which case comparing the timestamps on consecutive events may not be very meaningful.
– David Anderson
Nov 19 '18 at 8:09
BTW, the WikipediaEditEvent objects used in ci.apache.org/projects/flink/flink-docs-release-1.6/quickstart/… do have timestamps.
– David Anderson
Nov 19 '18 at 8:13
Do your events have event-time timestamps that you want to compare, or are you wanting to use the CPU clock to measure the interval between processing one event and the next?
– David Anderson
Nov 17 '18 at 9:45
Do your events have event-time timestamps that you want to compare, or are you wanting to use the CPU clock to measure the interval between processing one event and the next?
– David Anderson
Nov 17 '18 at 9:45
I intend to use event-time timestamps. So far, I am experimenting with the Twitter stream to gather some experience - do the tweet events have event timestamps ?
– Lars
Nov 18 '18 at 20:49
I intend to use event-time timestamps. So far, I am experimenting with the Twitter stream to gather some experience - do the tweet events have event timestamps ?
– Lars
Nov 18 '18 at 20:49
Make a window with size 2 and apply the function to get the difference, something looks like this:
text.flatMap(_.toLowerCase.split("\W+")).map((_, System.currentTimeMillis())).countWindowAll(2).apply[Long]((_, iter, c) => c.collect(iter.last._2 - iter.head._2)).print()– David
Nov 19 '18 at 2:32
Make a window with size 2 and apply the function to get the difference, something looks like this:
text.flatMap(_.toLowerCase.split("\W+")).map((_, System.currentTimeMillis())).countWindowAll(2).apply[Long]((_, iter, c) => c.collect(iter.last._2 - iter.head._2)).print()– David
Nov 19 '18 at 2:32
Keep in mind that most applications with event-time timestamps end up processing events that are out-of-order, in which case comparing the timestamps on consecutive events may not be very meaningful.
– David Anderson
Nov 19 '18 at 8:09
Keep in mind that most applications with event-time timestamps end up processing events that are out-of-order, in which case comparing the timestamps on consecutive events may not be very meaningful.
– David Anderson
Nov 19 '18 at 8:09
BTW, the WikipediaEditEvent objects used in ci.apache.org/projects/flink/flink-docs-release-1.6/quickstart/… do have timestamps.
– David Anderson
Nov 19 '18 at 8:13
BTW, the WikipediaEditEvent objects used in ci.apache.org/projects/flink/flink-docs-release-1.6/quickstart/… do have timestamps.
– David Anderson
Nov 19 '18 at 8:13
|
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Do your events have event-time timestamps that you want to compare, or are you wanting to use the CPU clock to measure the interval between processing one event and the next?
– David Anderson
Nov 17 '18 at 9:45
I intend to use event-time timestamps. So far, I am experimenting with the Twitter stream to gather some experience - do the tweet events have event timestamps ?
– Lars
Nov 18 '18 at 20:49
Make a window with size 2 and apply the function to get the difference, something looks like this:
text.flatMap(_.toLowerCase.split("\W+")).map((_, System.currentTimeMillis())).countWindowAll(2).apply[Long]((_, iter, c) => c.collect(iter.last._2 - iter.head._2)).print()– David
Nov 19 '18 at 2:32
Keep in mind that most applications with event-time timestamps end up processing events that are out-of-order, in which case comparing the timestamps on consecutive events may not be very meaningful.
– David Anderson
Nov 19 '18 at 8:09
BTW, the WikipediaEditEvent objects used in ci.apache.org/projects/flink/flink-docs-release-1.6/quickstart/… do have timestamps.
– David Anderson
Nov 19 '18 at 8:13