Hi Santoshakhilesh, I'd seen that already, but I was trying to avoid using rdds to perform this calculation.
@Ayan, it seems I was mistaken, and doing a sum(b) over(order by b) totally works. I guess I expected the windowing with sum to work more like oracle. Thanks for the suggestion :) Thank you both for your help, Jon On Tue, Aug 9, 2016 at 3:01 AM Santoshakhilesh <santosh.akhil...@huawei.com> wrote: > You could check following link. > > > http://stackoverflow.com/questions/35154267/how-to-compute-cumulative-sum-using-spark > > > > *From:* Jon Barksdale [mailto:jon.barksd...@gmail.com] > *Sent:* 09 August 2016 08:21 > *To:* ayan guha > *Cc:* user > *Subject:* Re: Cumulative Sum function using Dataset API > > > > I don't think that would work properly, and would probably just give me > the sum for each partition. I'll give it a try when I get home just to be > certain. > > To maybe explain the intent better, if I have a column (pre sorted) of > (1,2,3,4), then the cumulative sum would return (1,3,6,10). > > Does that make sense? Naturally, if ordering a sum turns it into a > cumulative sum, I'll gladly use that :) > > Jon > > On Mon, Aug 8, 2016 at 4:55 PM ayan guha <guha.a...@gmail.com> wrote: > > You mean you are not able to use sum(col) over (partition by key order by > some_col) ? > > > > On Tue, Aug 9, 2016 at 9:53 AM, jon <jon.barksd...@gmail.com> wrote: > > Hi all, > > I'm trying to write a function that calculates a cumulative sum as a column > using the Dataset API, and I'm a little stuck on the implementation. From > what I can tell, UserDefinedAggregateFunctions don't seem to support > windowing clauses, which I think I need for this use case. If I write a > function that extends from AggregateWindowFunction, I end up needing > classes > that are package private to the sql package, so I need to make my function > under the org.apache.spark.sql package, which just feels wrong. > > I've also considered writing a custom transformer, but haven't spend as > much > time reading through the code, so I don't know how easy or hard that would > be. > > TLDR; What's the best way to write a function that returns a value for > every > row, but has mutable state, and gets row in a specific order? > > Does anyone have any ideas, or examples? > > Thanks, > > Jon > > > > > -- > View this message in context: > http://apache-spark-user-list.1001560.n3.nabble.com/Cumulative-Sum-function-using-Dataset-API-tp27496.html > Sent from the Apache Spark User List mailing list archive at Nabble.com. > > --------------------------------------------------------------------- > To unsubscribe e-mail: user-unsubscr...@spark.apache.org > > > > > > -- > > Best Regards, > Ayan Guha > >
