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From ayan guha <guha.a...@gmail.com>
Subject Re: Cumulative Sum function using Dataset API
Date Tue, 09 Aug 2016 23:08:53 GMT
Thanks for reporting back. Glad it worked for you. Actually sum with
partitioning behaviour is same in oracle too.
On 10 Aug 2016 03:01, "Jon Barksdale" <jon.barksdale@gmail.com> wrote:

> 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.akhilesh@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.barksdale@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.ayan@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.barksdale@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.
>>
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>>
>>
>>
>>
>> --
>>
>> Best Regards,
>> Ayan Guha
>>
>>

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