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From "Alfonso Nishikawa (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (GORA-401) Serialization and deserialization of Persistent does not hold the entity dirty state from Map to Reduce
Date Tue, 03 Feb 2015 20:12:35 GMT

    [ https://issues.apache.org/jira/browse/GORA-401?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14303885#comment-14303885
] 

Alfonso Nishikawa commented on GORA-401:
----------------------------------------

@Henry: I have noticed now...

There is not need for tests in other datastores. As you say, there should not be any changes
needed in specific datastore module. I should have implemented it in gora-core in a job using
avro store, but I did it in HBase because I was working with it. Right. I will implement that
tests in gora-core and delete it from gora-hbase.

You are right. Thanks for commenting it.

> 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: 0.7
>
>         Attachments: GORA-401-tests.patch, GORA-401v1.patch, GORA-401v2.patch, GORA-401v3.patch,
GORA-401v4.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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