Pig is broken with speculative execution
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Key: PIG-250
URL: https://issues.apache.org/jira/browse/PIG-250
Project: Pig
Issue Type: Bug
Reporter: Olga Natkovich
If I have speculative execution turned on, the following script fails:
a = load 'studenttab20m' as (name, age, gpa);
b = load 'votertab10k' as (name, age, registration, contributions);
c = filter a by age < '50';
d = filter b by age < '50';
e = cogroup c by (name, age), d by (name, age) parallel 10;
f = foreach e generate flatten(c), flatten(d) parallel 10;
g = group f by registration parallel 10;
h = foreach g generate group, SUM(f.d::contributions) parallel 10;
i = order h by ($1, $0);
store i into 'out';
I traced this to the fact that the first MR job produces one or more empty
outputs from the reducer. This happened on the reducers that happened to have
second task running.
I am not sure what the issue is and I am working with hadoop guys to
investigate. Until this issue is resolved, I would like to trun speculative
execution off.
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