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https://issues.apache.org/jira/browse/ARROW-3247?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Martin Durant updated ARROW-3247:
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Summary: Support spark parquet array and map types (was: Support spark
array and map types)
> Support spark parquet array and map types
> -----------------------------------------
>
> Key: ARROW-3247
> URL: https://issues.apache.org/jira/browse/ARROW-3247
> Project: Apache Arrow
> Issue Type: Improvement
> Components: Python
> Reporter: Martin Durant
> Priority: Minor
>
> As far I understand, there is already some support for nested
> array/dict/structs in arrow. However, spark Map and List types are structured
> one level deeper (I believe to allow for both NULL and empty entries).
> Surprisingly, fastparquet can load these. I do not know the plan for
> arbitrary nested object support, but it should be made clear.
> Schema of spark-generated file from the fastparquet test suite (please see in
> text mode):
> - spark_schema:
> | - map_op_op: MAP, OPTIONAL
> | - key_value: REPEATED
> | | - key: BYTE_ARRAY, UTF8, REQUIRED
> | - value: BYTE_ARRAY, UTF8, OPTIONAL
> | - map_op_req: MAP, OPTIONAL
> | - key_value: REPEATED
> | | - key: BYTE_ARRAY, UTF8, REQUIRED
> | - value: BYTE_ARRAY, UTF8, REQUIRED
> | - map_req_op: MAP, REQUIRED
> | - key_value: REPEATED
> | | - key: BYTE_ARRAY, UTF8, REQUIRED
> | - value: BYTE_ARRAY, UTF8, OPTIONAL
> | - map_req_req: MAP, REQUIRED
> | - key_value: REPEATED
> | | - key: BYTE_ARRAY, UTF8, REQUIRED
> | - value: BYTE_ARRAY, UTF8, REQUIRED
> | - arr_op_op: LIST, OPTIONAL
> | - list: REPEATED
> | - element: BYTE_ARRAY, UTF8, OPTIONAL
> | - arr_op_req: LIST, OPTIONAL
> | - list: REPEATED
> | - element: BYTE_ARRAY, UTF8, REQUIRED
> | - arr_req_op: LIST, REQUIRED
> | - list: REPEATED
> | - element: BYTE_ARRAY, UTF8, OPTIONAL
> - arr_req_req: LIST, REQUIRED
> - list: REPEATED
> - element: BYTE_ARRAY, UTF8, REQUIRED
> (please forgive that some of this has already been mentioned elsewhere; this
> is one of the entries in the list at
> https://github.com/dask/fastparquet/issues/374 as a feature that is useful in
> fastparquet)
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