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https://issues.apache.org/jira/browse/PARQUET-2069?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17519231#comment-17519231
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Timothy Miller commented on PARQUET-2069:
-----------------------------------------
With the original file, the debug message says this instead:
[main] DEBUG org.apache.avro.SchemaCompatibility - Checking compatibility of
reader
\{"type":"record","name":"list","fields":[{"name":"element","type":["null","string"],"default":null}]}
with
writer
\{"type":"record","name":"list","fields":[{"name":"element","type":["null","string"],"default":null}]}
What I can't figure out is why the the reader record name is "list" in the
modified case, since all the lists in the original were converted to arrays. So
it should also be an array.
> Parquet file containing arrays, written by Parquet-MR, cannot be read again
> by Parquet-MR
> -----------------------------------------------------------------------------------------
>
> Key: PARQUET-2069
> URL: https://issues.apache.org/jira/browse/PARQUET-2069
> Project: Parquet
> Issue Type: Bug
> Components: parquet-avro
> Affects Versions: 1.12.0
> Environment: Windows 10
> Reporter: Devon Kozenieski
> Priority: Blocker
> Attachments: modified.parquet, original.parquet, parquet-diff.png
>
>
> In the attached files, there is one original file, and one written modified
> file that results after reading the original file and writing it back with
> Parquet-MR, with a few values modified. The schema should not be modified,
> since the schema of the input file is used as the schema to write the output
> file. However, the output file has a slightly modified schema that then
> cannot be read back the same way again with Parquet-MR, resulting in the
> exception message: java.lang.ClassCastException: optional binary element
> (STRING) is not a group
> My guess is that the issue lies in the Avro schema conversion.
> The Parquet files attached have some arrays and some nested fields.
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