Actually that doesn't work as expected because emitted values are not purged. I'll experiment with purging triggers and/or evictors, though I have the feeling that Flink was not designed for what we need to do here -- but I'll keep on searching.
In the meantime any advice is appreciated. If the goal is not clear I can provide more details. Thank you, Denis From: Dollfus, Denis (TR Technology & Ops) Sent: lundi 5 décembre 2016 16:31 To: user@flink.apache.org Subject: RE: Equivalent of Rx combineLatest() on a join? Asking the response helped me to find the answer (yes, rubber duck debugging<https://urldefense.proofpoint.com/v2/url?u=https-3A__en.wikipedia.org_wiki_Rubber-5Fduck-5Fdebugging&d=CwMFAw&c=4ZIZThykDLcoWk-GVjSLm9hvvvzvGv0FLoWSRuCSs5Q&r=Jtkfol_Mg_eQUL17wcicdBE1Et94D7zgzS-8_bKvGlc&m=NNcjpWPJ7g8qY8aDVqKnFusNJenvEDh4gSVH9oN596Y&s=jzjcaGPpNnYAs8WTsdAtUBisrQxT234_JP59ZzJgyCw&e=>) as it seems that the code below does what I need: s3 = s1.join(s2) .where(new KeySelector1()).equalTo(new KeySelector2()) .window(GlobalWindow.create()) .trigger(CountTrigger.of(1)) .apply(new JoinFunction<a,b,c>); If that's a common use case (in my view it is), a syntax shortcut could help developers, e.g. something like: s3 = s1.join(s2) .where(new KeySelector1()).equalTo(new KeySelector2()) .combineLatest(new JoinFunction<a,b,c>); Denis From: Dollfus, Denis (TR Technology & Ops) Sent: lundi 5 décembre 2016 12:27 To: user@flink.apache.org<mailto:user@flink.apache.org> Subject: Equivalent of Rx combineLatest() on a join? Hi all, [first email here, I'm new to Flink, Java and Scala, sorry if I missed something obvious] I'm exploring Flink in the context of streaming calculators. Basically, the data flow boils down to multiple data streams with variable update rates (ms, seconds, ..., month) which are joined before being fed to calculators. The kind of operation I need is very similar to the Rx combineLatest<https://urldefense.proofpoint.com/v2/url?u=http-3A__reactivex.io_documentation_operators_combinelatest.html&d=CwMFAg&c=4ZIZThykDLcoWk-GVjSLm9hvvvzvGv0FLoWSRuCSs5Q&r=Jtkfol_Mg_eQUL17wcicdBE1Et94D7zgzS-8_bKvGlc&m=XIk_LOnCw3IK_rNsQ5k4Y7nX14-RXxpT2wgnexTL2nM&s=HqeoR2u4r5RCZ6OjcCRP6usy9b8iUuZU3xxU6Sk17yg&e=> operator, which results in a object being emitted whenever one of the streams is updated. As there is no such operator predefined, I think I have to use a GlobalWindow and provide a custom WindowAssigner. The end result would look like this (pseudo java 8 code, I hope it's understandable): DataStream<price1> s1 = env.addSource(..); DataStream<price2> s2 = env.addSource(..); S3 = s1.join(s2) .where(s1 -> id) .equalTo(s2 -> id) .window(new MyCustomCombineLatestAssigner()) .apply( ... return new object combining data from s1 and from s2); Is the approach correct, or is there a simpler way to achieve the same join + apply mechanism ? Thank you, Denis ________________________________ This e-mail is for the sole use of the intended recipient and contains information that may be privileged and/or confidential. If you are not an intended recipient, please notify the sender by return e-mail and delete this e-mail and any attachments. Certain required legal entity disclosures can be accessed on our website.<http://site.thomsonreuters.com/site/disclosures/>
