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https://issues.apache.org/jira/browse/PIG-4298?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daniel Dai updated PIG-4298:
----------------------------
Attachment: PIG-4298-2.patch
Fix looks good.
I added a test case in the new patch.
> 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
>
> Attachments: PIG-4298-1.patch, PIG-4298-2.patch, repo.tar.gz
>
>
> 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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