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List:       avro-dev
Subject:    [jira] [Commented] (AVRO-2148) Avro: Schema compatibility/evolution - attribute size change
From:       "Ashok (JIRA)" <jira () apache ! org>
Date:       2018-02-21 23:16:00
Message-ID: JIRA.13140059.1519254530000.247162.1519254960938 () Atlassian ! JIRA
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    [ https://issues.apache.org/jira/browse/AVRO-2148?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16372187#comment-16372187 \
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Ashok commented on AVRO-2148:
-----------------------------

FYI, Hive avro deserializer is being used to  read the Avro data files and that \
requires to be associated with a schema.   Without being able to evolve the schema, \
parsing the data of multiple versions will get difficult and hence the need to allow \
the above

> Avro: Schema compatibility/evolution - attribute size change
> ------------------------------------------------------------
> 
> Key: AVRO-2148
> URL: https://issues.apache.org/jira/browse/AVRO-2148
> Project: Avro
> Issue Type: Improvement
> Components: java
> Affects Versions: 1.8.2
> Reporter: Ashok
> Priority: Critical
> 
> Let's assume the schema changed from V1 to V2.   Currently, we can't create a  \
> merge of the two schema that makes it a compatible for both.    Depending on what  \
> size we keep in the reader schema  (the merged schema), you can only read avro \
> files of schema V1 or V2, not both.   If we keep the higher attribute size value \
> (64), it should allow the read of avro files with lower attribute size value (16) 
> * *V1 schema:*
> { "name": "sid", "type": [ "null",
> { "type": "fixed", "name": "SID", "namespace": "com.int.datatype", "doc": "", \
> "size": *64* } ], "doc": "", "default": null, "businessLogic": "" }
> 
> * *V2 schema:*
> { "name": "sid", "type": [ "null",
> { "type": "fixed", "name": "SID", "namespace": "com.int.datatype", "doc": "", \
> "size": *16* } ], "doc": "", "default": null, "businessLogic": "" }



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