Thanks Gábor, but the first sum call will return SingleOutputStreamOperator
I could not do another sum call on that. Would tell me how did you manage to do stream.sum().sum() Regards, -Rami On 7 Jun 2016, at 16:13, Gábor Gévay <gga...@gmail.com<mailto:gga...@gmail.com>> wrote: Hello, In the case of "sum", you can just specify them one after the other, like: stream.sum(1).sum(2) This works, because summing the two fields are independent. However, in the case of "keyBy", the information is needed from both fields at the same time to produce the key. Best, Gábor 2016-06-07 14:41 GMT+02:00 Al-Isawi Rami <rami.al-is...@comptel.com<mailto:rami.al-is...@comptel.com>>: Hi, Is there any reason why “keyBy" accepts multi-field, while for example “sum” does not. -Rami Disclaimer: This message and any attachments thereto are intended solely for the addressed recipient(s) and may contain confidential information. If you are not the intended recipient, please notify the sender by reply e-mail and delete the e-mail (including any attachments thereto) without producing, distributing or retaining any copies thereof. Any review, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient(s) is prohibited. Thank you. Disclaimer: This message and any attachments thereto are intended solely for the addressed recipient(s) and may contain confidential information. If you are not the intended recipient, please notify the sender by reply e-mail and delete the e-mail (including any attachments thereto) without producing, distributing or retaining any copies thereof. Any review, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient(s) is prohibited. Thank you.
