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From Renato Javier Marroquín Mogrovejo (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 Mon, 09 Feb 2015 14:39:35 GMT

    [ https://issues.apache.org/jira/browse/GORA-401?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14312287#comment-14312287
] 

Renato Javier Marroquín Mogrovejo commented on GORA-401:
--------------------------------------------------------

But isn't going from one JVM to another the same thing like going from Map to Reduce phase?
Maybe there is a way to also address this in this way. Do you think that would be possible
Alfonso? I will try to look into this issue the following weeks so maybe we can reach consensus
on getting this.
Awesome work Alfonso!

> 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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