Get side output (events where join didn't succeed) for IntervalJoin

[Daksh Talwar]

Hi,

I'm exploring Interval Join as a probable solution for joins between two streams of data, with a long lookback period. While going through the official documentation, I couldn't figure out a way to get events where there was no join in the interval.

From the example quoted in the official doc (pasted below), how do I get the events from orangeStream that did not join with any event in greenStream in the [-2,+1] interval?

DataStream<Integer> orangeStream = ...
DataStream<Integer> greenStream = ...

orangeStream
    .keyBy(<KeySelector>)
    .intervalJoin(greenStream.keyBy(<KeySelector>))
    .between(Time.milliseconds(-2), Time.milliseconds(1))
    .process (new ProcessJoinFunction<Integer, Integer, String(){

        @Override
        public void processElement(Integer left, Integer right, Context ctx, Collector<String> out) {
            out.collect(first + "," + second);
        }
    });

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[Guowei Ma]

Hi,

AFAIK, the `intervalJoin` of the DataStream could not do that. But I think you could try the SQL's intervalJoin[1] and you could find some examples in the `IntervalJoinITCase`[2].

[1] https://ci.apache.org/projects/flink/flink-docs-release-1.12/dev/table/sql/queries.html#joins

[2] https://github.com/apache/flink/blob/59ae84069313ede60cf7ad3a9d2fe1bc07c4e460/flink-table/flink-table-planner-blink/src/test/scala/org/apache/flink/table/planner/runtime/stream/sql/IntervalJoinITCase.scala

On Wed, Mar 17, 2021 at 5:06 PM Daksh Talwar <[hidden email]> wrote:

Hi,

I'm exploring Interval Join as a probable solution for joins between two streams of data, with a long lookback period. While going through the official documentation, I couldn't figure out a way to get events where there was no join in the interval.

From the example quoted in the official doc (pasted below), how do I get the events from orangeStream that did not join with any event in greenStream in the [-2,+1] interval?

DataStream<Integer> orangeStream = ...
DataStream<Integer> greenStream = ...

orangeStream
    .keyBy(<KeySelector>)
    .intervalJoin(greenStream.keyBy(<KeySelector>))
    .between(Time.milliseconds(-2), Time.milliseconds(1))
    .process (new ProcessJoinFunction<Integer, Integer, String(){

        @Override
        public void processElement(Integer left, Integer right, Context ctx, Collector<String> out) {
            out.collect(first + "," + second);
        }
    });

Cheers,
Daksh

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This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error, please notify the system manager. This message contains confidential information and is intended only for the individual named. If you are not the named addressee, you should not disseminate, distribute or copy this email. Please notify the sender immediately by email if you have received this email by mistake and delete this email from your system. If you are not the intended recipient, you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.

 

Any views or opinions presented in this email are solely those of the author and do not necessarily represent those of the organization. Any information on shares, debentures or similar instruments, recommended product pricing, valuations and the like are for information purposes only. It is not meant to be an instruction or recommendation, as the case may be, to buy or to sell securities, products, services nor an offer to buy or sell securities, products or services unless specifically stated to be so on behalf of the Flipkart group. Employees of the Flipkart group of companies are expressly required not to make defamatory statements and not to infringe or authorise any infringement of copyright or any other legal right by email communications. Any such communication is contrary to organizational policy and outside the scope of the employment of the individual concerned. The organization will not accept any liability in respect of such communication, and the employee responsible will be personally liable for any damages or other liability arising.

 

Our organization accepts no liability for the content of this email, or for the consequences of any actions taken on the basis of the information provided, unless that information is subsequently confirmed in writing. If you are not the intended recipient, you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.

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