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Pig, mail # user - CROSS/Self-Join Bug - Please Help :(


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Re: CROSS/Self-Join Bug - Please Help :(
Pradeep Gollakota 2013-12-04, 21:41
I tried to following script (not exactly the same) and it worked correctly
for me.

businesses = LOAD 'dataset' using PigStorage(',') AS (a, b, c,
business_id: chararray, lat: double, lng: double);
locations = FOREACH businesses GENERATE business_id, lat, lng;
STORE locations INTO 'locations.tsv';
locations2 = LOAD 'locations.tsv' AS (business_id, lat, long);
loc_com = CROSS locations2, locations;
dump loc_com;

I’m wondering your problem has something to do with the way that the
JsonStorage works. Another thing you can try is to load ‘locations.tsv’
twice and do a self-cross on that.
On Wed, Dec 4, 2013 at 1:21 PM, Russell Jurney <[EMAIL PROTECTED]>wrote:

> I have this bug that is killing me, where I can't self-join/cross a dataset
> with itself. Its blocking my work :(
>
> The script is like this:
>
> businesses = LOAD
> 'yelp_phoenix_academic_dataset/yelp_academic_dataset_business.json' using
> com.twitter.elephantbird.pig.load.JsonLoader() as json:map[];
>
> /* {open=true, neighborhoods={}, review_count=14, stars=4.0, name=Drybar,
> business_id=LcAamvosJu0bcPgEVF-9sQ, state=AZ, full_address=3172 E Camelback
> Rd
> Phoenix, AZ85018, categories={(Hair Salons),(Hair Stylists),(Beauty &
> Spas)}, longitude=-112.0131927, latitude=33.5107772, type=business,
> city=Phoenix} */
> locations = FOREACH businesses GENERATE $0#'business_id' AS business_id,
>                                       $0#'longitude' AS longitude,
>                                       $0#'latitude' AS latitude;
> STORE locations INTO 'yelp_phoenix_academic_dataset/locations.tsv';
> locations_2 = LOAD 'yelp_phoenix_academic_dataset/locations.tsv' AS
> (business_id:chararray, longitude:double, latitude:double);
> location_comparisons = CROSS locations_2, locations;
>
> distances = FOREACH businesses GENERATE locations.business_id AS
> business_id_1,
>                                         locations_2.business_id AS
> business_id_2,
>                                         udfs.haversine(locations.longitude,
>                                                        locations.latitude,
>
>  locations_2.longitude,
>
>  locations_2.latitude) AS distance;
> STORE distances INTO 'yelp_phoenix_academic_dataset/distances.tsv';
>
>
> I have also tried converting this to a self-join using JOIN BY '1', and
> also locations_2 = locations, and I get the same error:
>
> *org.apache.pig.backend.executionengine.ExecException: ERROR 0: Scalar has
> more than one row in the output. 1st :
> (rncjoVoEFUJGCUoC1JgnUA,-112.241596,33.581867), 2nd
> :(0FNFSzCFP_rGUoJx8W7tJg,-112.105933,33.604054)*
>
> at org.apache.pig.impl.builtin.ReadScalars.exec(ReadScalars.java:111)
>
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POUserFunc.getNext(POUserFunc.java:336)
>
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POUserFunc.getNext(POUserFunc.java:438)
>
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator.getNext(PhysicalOperator.java:347)
>
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.processPlan(POForEach.java:378)
>
> at
>
> org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.getNext(POForEach.java:298)
>
> at
>
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.runPipeline(PigGenericMapBase.java:283)
>
> at
>
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.map(PigGenericMapBase.java:278)
>
> at
>
> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigGenericMapBase.map(PigGenericMapBase.java:64)
>
> at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
>
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)
>
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
>
> at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:212)
>
> This makes no sense! What am I to do? I can't self-join :(