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From "Alfonso Nishikawa (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (GORA-401) Serialization and deserialization of Persistent does not hold the entity dirty state from Map to Reduce
Date Sun, 18 Sep 2016 22:57:20 GMT

    [ https://issues.apache.org/jira/browse/GORA-401?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15501785#comment-15501785
] 

Alfonso Nishikawa edited comment on GORA-401 at 9/18/16 10:56 PM:
------------------------------------------------------------------

Wow, [~djkevincr], that was a pretty neat patch! Many thanks!

My solution was based on modifying PersistentDatumReader/Writer, but your approach looks better
after comparing :)

The only thing I miss is an actual test in a Map-Reduce process. I am a quite conservative
person, so if you can take the test from GORA-401v5.patch and your fix passes that test too,
I will be fully convinced about your solution :)
The tests are for gora-hbase, but if they pass there, they _should_ pass in everyone (except
MemStore and AvroStore).

The files from GORA-401v5.patch would be:

* TestHBaseStoreMapReduceSerialization.java
* MapReduceTestUtils.java#testMapReduceSerialization()

Could you take a look at that test?


was (Author: alfonso.nishikawa):
Wow, [~djkevincr], that was a pretty neat patch! Many thanks!

My solution was based on modifying PersistentDatumReader/Writer, but your approach looks better
after comparing :)

The only thing I miss is an actual test in a Map-Reduce process. I am a quite conservative
person, so if you can take the test from GORA-401v5.patch and your fix passes that test too,
I will be fully convinced about your solution :)
The tests are for gora-hbase, but if they pass there, they _should_ pass in everyone -except
MemStore and AvroStore-.

The files from GORA-401v5.patch would be:

* TestHBaseStoreMapReduceSerialization.java
* MapReduceTestUtils.java#testMapReduceSerialization()

Could you take a look at that test?

> Serialization and deserialization of Persistent does not hold the entity dirty state
from Map to Reduce
> -------------------------------------------------------------------------------------------------------
>
>                 Key: GORA-401
>                 URL: https://issues.apache.org/jira/browse/GORA-401
>             Project: Apache Gora
>          Issue Type: Bug
>          Components: gora-core
>    Affects Versions: 0.4, 0.5
>         Environment: Tested on gora-0.4, but seems logically to hold on gora-0.5. HBase
backend.
>            Reporter: Alfonso Nishikawa
>            Assignee: Alfonso Nishikawa
>            Priority: Critical
>              Labels: serialization
>             Fix For: 0.8
>
>         Attachments: GORA-401-tests.patch, GORA-401v1.patch, GORA-401v2.patch, GORA-401v3.patch,
GORA-401v4.patch, GORA-401v5.patch
>
>   Original Estimate: 35h
>          Time Spent: 21h
>  Remaining Estimate: 14h
>
> After removing __g__dirty field in GORA-326, dirty field is not serialized. In GORA-321
{{[PersistentSerializer|https://github.com/apache/gora/blob/master/gora-core/src/main/java/org/apache/gora/mapreduce/PersistentSerializer.java]}}
went from using {{[PersistentDatumWriter|https://github.com/apache/gora/blob/apache-gora-0.3/gora-core/src/main/java/org/apache/gora/avro/PersistentDatumWriter.java](/Reader)}}
to Avro's {{SpecificDatumWriter}}, delegating the serialization of the dirty field to Avro
(but really not desirable to have that field as a main field in the entities).
> The proposal is to reintroduce the {{PersistentDatumWriter/Reader}} which will serialize
the internal fields of the entities.
> This bug affects, for example, Nutch, which loads only some fields in it's phases, serializes
entities (from Map to Reduce), and when deserializes finds all fields as "dirty", independently
of what fields were modified in the Map, and overwrite all data in datastore (deleting much
things: downloaded content, parsed content, etc).
> This effect can be seen in {{TestPersistentSerialization#testSerderEmployeeTwoFields}},
when debuging in {{TestIOUtils#testSerializeDeserialize}}. Proper breakpoints an inspections
shows that, entities are "equal" when it's fields are equal. This is fine as "equal" definition,
but another test must be added to check that serialization an deserialization keeps the dirty
state.



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