Why removing the destination from the window wont work? Like this: *trainTimesDataset* * .withWatermark("**activity_timestamp", "5 days")* * .groupBy(window(activity_timestamp, "24 hours", "24 hours"), "train")* * .max("time")*
On Wed, Aug 30, 2017 at 10:38 AM, kant kodali <kanth...@gmail.com> wrote: > @Burak so how would the transformation or query would look like for the > above example? I don't see flatMapGroupsWithState in the DataSet API > Spark 2.1.1. I may be able to upgrade to 2.2.0 if that makes life easier. > > > > On Tue, Aug 29, 2017 at 5:25 PM, Burak Yavuz <brk...@gmail.com> wrote: > >> Hey TD, >> >> If I understood the question correctly, your solution wouldn't return the >> exact solution, since it also groups by on destination. I would say the >> easiest solution would be to use flatMapGroupsWithState, where you: >> .groupByKey(_.train) >> >> and keep in state the row with the maximum time. >> >> On Tue, Aug 29, 2017 at 5:18 PM, Tathagata Das < >> tathagata.das1...@gmail.com> wrote: >> >>> Yes. And in that case, if you just care about only the last few days of >>> max, then you should set watermark on the timestamp column. >>> >>> *trainTimesDataset* >>> * .withWatermark("**activity_timestamp", "5 days")* >>> * .groupBy(window(activity_timestamp, "24 hours", "24 hours"), "train", >>> "dest")* >>> * .max("time")* >>> >>> Any counts which are more than 5 days old will be dropped from the >>> streaming state. >>> >>> On Tue, Aug 29, 2017 at 2:06 PM, kant kodali <kanth...@gmail.com> wrote: >>> >>>> Hi, >>>> >>>> Thanks for the response. Since this is a streaming based query and in >>>> my case I need to hold state for 24 hours which I forgot to mention in my >>>> previous email. can I do ? >>>> >>>> *trainTimesDataset.groupBy(window(activity_timestamp, "24 hours", "24 >>>> hours"), "train", "dest").max("time")* >>>> >>>> >>>> On Tue, Aug 29, 2017 at 1:38 PM, Tathagata Das < >>>> tathagata.das1...@gmail.com> wrote: >>>> >>>>> Say, *trainTimesDataset* is the streaming Dataset of schema *[train: >>>>> Int, dest: String, time: Timestamp] * >>>>> >>>>> >>>>> *Scala*: *trainTimesDataset.groupBy("train", "dest").max("time")* >>>>> >>>>> >>>>> *SQL*: *"select train, dest, max(time) from trainTimesView group by >>>>> train, dest"* // after calling >>>>> *trainTimesData.createOrReplaceTempView(trainTimesView)* >>>>> >>>>> >>>>> On Tue, Aug 29, 2017 at 12:59 PM, kant kodali <kanth...@gmail.com> >>>>> wrote: >>>>> >>>>>> Hi All, >>>>>> >>>>>> I am wondering what is the easiest and concise way to express the >>>>>> computation below in Spark Structured streaming given that it supports >>>>>> both >>>>>> imperative and declarative styles? >>>>>> I am just trying to select rows that has max timestamp for each >>>>>> train? Instead of doing some sort of nested queries like we normally do >>>>>> in >>>>>> any relational database I am trying to see if I can leverage both >>>>>> imperative and declarative at the same time. If nested queries or join >>>>>> are >>>>>> not required then I would like to see how this can be possible? I am >>>>>> using >>>>>> spark 2.1.1. >>>>>> >>>>>> Dataset >>>>>> >>>>>> Train Dest Time1 HK 10:001 SH 12:001 >>>>>> SZ 14:002 HK 13:002 SH 09:002 >>>>>> SZ 07:00 >>>>>> >>>>>> The desired result should be: >>>>>> >>>>>> Train Dest Time1 SZ 14:002 HK 13:00 >>>>>> >>>>>> >>>>> >>>> >>> >> > -- Best Regards, Ayan Guha