Skewed join sampler generates unevenly partitioned data
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Key: PIG-1743
URL: https://issues.apache.org/jira/browse/PIG-1743
Project: Pig
Issue Type: Bug
Components: impl
Affects Versions: 0.7.0, 0.8.0
Reporter: Viraj Bhat
I have a data, when using the Skewed join generated uneven partitions. The
script looks like this:
{script}
Data1 = LOAD '/user/viraj/relation1.in' AS (ref,intVal);
Data2 = LOAD '/user/viraj/relation2.in' using PigStorage('\u0001') AS
(ID:chararray, Key:chararray, DomainKey:chararray);
JoinData = JOIN Data1 BY ref LEFT OUTER , Data2 BY ID using 'skewed' PARALLEL
10;
STORE JoinData into 'skewedoutput' using PigStorage('\u0001');
{script}
The output generated has the following part files of varying sizes
{quote}
$ hadoop fs -ls /user/viraj/skewedoutput
Found 10 items
-rw------- 3 viraj users 2090 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00000
-rw------- 3 viraj users 19380 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00001
-rw------- 3 viraj users 2090 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00002
-rw------- 3 viraj users 9690 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00003
-rw------- 3 viraj users 2090 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00004
-rw------- 3 viraj users 2090 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00005
-rw------- 3 viraj users 0 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00006
-rw------- 3 viraj users 0 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00007
-rw------- 3 viraj users 0 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00008
-rw------- 3 viraj users 0 2010-11-23 03:44
/user/viraj/skewedoutput/part-r-00009
{quote}
Attaching input datasets.
Viraj
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