Cheolsoo Park created PIG-4298:
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             Summary: Descending order-by is broken in some cases when key is 
bytearrays 
                 Key: PIG-4298
                 URL: https://issues.apache.org/jira/browse/PIG-4298
             Project: Pig
          Issue Type: Bug
            Reporter: Cheolsoo Park
            Assignee: Cheolsoo Park
             Fix For: 0.15.0


Here is a repo script (using [PigPen|https://github.com/Netflix/PigPen])-
{code}
REGISTER pigpen.jar;

load4254 = LOAD 'input.clj'
    USING PigStorage('\n')
    AS (value:chararray);

DEFINE udf4265 pigpen.PigPenFnDataBag('(clojure.core/require (quote 
[pigpen.runtime]) (quote [clojure.edn]))','(pigpen.runtime/exec 
[(pigpen.runtime/process->bind (pigpen.runtime/pre-process :pig :native)) 
(pigpen.runtime/map->bind clojure.edn/read-string) 
(pigpen.runtime/key-selector->bind clojure.core/identity) 
(pigpen.runtime/process->bind (pigpen.runtime/post-process :pig 
:native-key-frozen-val))])');

generate4263 = FOREACH load4254 GENERATE
    FLATTEN(udf4265(value));
generate4257 = FOREACH generate4263 GENERATE
    $0 AS key,
    $1 AS value;

order4258 = ORDER generate4257 BY key DESC; <-- sort order isn't changed by DESC
dump order4258;
{code}
This script returns the same result for both ASC and DESC orders.

The problem is as follows-
# {{PigBytesRawComparator}} calls {{BinInterSedesTupleRawComparator.compare()}}.
# {{BinInterSedesTupleRawComparator}} applies descending order.
# {{PigBytesRawComparator}} applies descending order again to what 
{{BinInterSedesTupleRawComparator}} returns.

Therefore, descending order is never applied.



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