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From ayan guha <guha.a...@gmail.com>
Subject Re: Assign unique link ID
Date Sat, 31 Oct 2015 13:00:31 GMT
Hi

The way I see it, your dedup condition needs to be defined. If you have it
variable, then the joining approach is no good either. You may want to stub
columns (like putting a default value in the joining clause) to achieve
this. If not, you would probably state the problem with all other
conditions so we can discuss further?

Getting a partition key upfront will be important in your case to control
shuffle.

Best
Ayan

On Sat, Oct 31, 2015 at 11:54 PM, Sarath Chandra <
sarathchandra.josyam@algofusiontech.com> wrote:

> Thanks for the reply Ayan.
>
> I got this idea earlier but the problem is the number of columns used for
> joining will be varying depending on the some data conditions. Also their
> data types will be different. So I'm not getting how to define the UDF as
> we need to upfront specify the argument count and their types.
>
> Any ideas how to tackle this?
>
> Regards,
> Sarath.
>
> On Sat, Oct 31, 2015 at 4:37 PM, ayan guha <guha.ayan@gmail.com> wrote:
>
>> Can this be a solution?
>>
>> 1. Write a function which will take a string and convert to md5 hash
>> 2. From your base table, generate a string out of all columns you have
>> used for joining. So, records 1 and 4 should generate same hash value.
>> 3. group by using this new id (you have already linked the records) and
>> pull out required fields.
>>
>> Please let the group know if it works...
>>
>> Best
>> Ayan
>>
>> On Sat, Oct 31, 2015 at 6:44 PM, Sarath Chandra <
>> sarathchandra.josyam@algofusiontech.com> wrote:
>>
>>> Hi All,
>>>
>>> I have a hive table where data from 2 different sources (S1 and S2) get
>>> accumulated. Sample data below -
>>>
>>>
>>> *RECORD_ID|SOURCE_TYPE|TRN_NO|DATE1|DATE2|BRANCH|REF1|REF2|REF3|REF4|REF5|REF6|DC_FLAG|AMOUNT|CURRENCY*
>>>
>>> *1|S1|55|19-Oct-2015|19-Oct-2015|25602|999|9999|41106|47311|379|99999|004|999|9999|Cr|2672.000000|INR*
>>>
>>> *2|S1|55|19-Oct-2015|19-Oct-2015|81201|999|9999|41106|99999|379|99999|004|999|9999|Dr|2672.000000|INR*
>>>
>>> *3|S2|55|19-OCT-2015|19-OCT-2015|81201|999|9999|41106|99999|379|99999|004|999|9999|DR|2672|INR*
>>>
>>> *4|S2|55|19-OCT-2015|19-OCT-2015|25602|999|9999|41106|47311|379|99999|004|999|9999|CR|2672|INR*
>>>
>>> I have a requirement to link similar records (same dates, branch and
>>> reference numbers) source wise and assign them unique ID linking the 2
>>> records. For example records 1 and 4 above should be linked with same ID.
>>>
>>> I've written code below to segregate data source wise and join them
>>> based on the similarities. But not knowing how to proceed further.
>>>
>>> *var hc = new org.apache.spark.sql.hive.HiveContext(sc);*
>>> *var src = hc.sql("select
>>> RECORD_ID,SOURCE,TRN_NO,DATE1,DATE2,BRANCH,REF1,REF2,REF3,REF4,REF5,REF6,DC_FLAG,AMOUNT,CURRENCY
>>> from src_table");*
>>>
>>> *var s1 = src.filter("source_type='S1'");*
>>>
>>> *var s2 = src.filter("source_type='S2'");*
>>> *var src_join = s1.as <http://s1.as>("S1").join(s2.as
>>> <http://s2.as>("S2")).filter("(S1.TRN_NO= S2.TRN_NO) and (S1.DATE1=
>>> S2.DATE1) and (S1.DATE2= S2.DATE2) and (S1.BRANCH= S2.BRANCH) and (S1.REF1=
>>> S2.REF1) and (S1.REF2= S2.REF2) and (S1.REF3= S2.REF3) and (S1.REF4=
>>> S2.REF4) and (S1.REF5= S2.REF5) and (S1.REF6= S2.REF6) and (S1.CURRENCY=
>>> S2.CURRENCY)");*
>>>
>>> Tried using a UDF which returns a random value or hashed string using
>>> record IDs of both sides and include it to schema using withColumn, but
>>> ended up getting duplicate link IDs.
>>>
>>> Also when I use a UDF I'm not able to refer to the columns using the
>>> alias in next steps. For example if I create a new DF using below line -
>>> *var src_link = src_join.as
>>> <http://src_join.as>("SJ").withColumn("LINK_ID",
>>> linkIDUDF(src_join("S1.RECORD_ID"),src("S2.RECORD_ID")));*
>>> Then in further lines I'm not able to refer to "s1" columns from
>>> "src_link" like -
>>> *var src_link_s1 = src_link.as
>>> <http://src_link.as>("SL").select($"S1.RECORD_ID");*
>>>
>>> Please guide me.
>>>
>>> Regards,
>>> Sarath.
>>>
>>
>>
>>
>> --
>> Best Regards,
>> Ayan Guha
>>
>
>


-- 
Best Regards,
Ayan Guha

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