[jira] [Updated] (ARROW-11497) [Python] pyarrow parquet writer for list does not conform with Apache Parquet specification

["Truc Lam Nguyen (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-11497?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Truc Lam Nguyen updated ARROW-11497:
------------------------------------
    Summary: [Python] pyarrow parquet writer for list does not conform with Apache Parquet specification  (was: [Python] pyarrow parquet writer for list does not conform with Apache Parquet sepecification)

> [Python] pyarrow parquet writer for list does not conform with Apache Parquet specification
> -------------------------------------------------------------------------------------------
>
>                 Key: ARROW-11497
>                 URL: https://issues.apache.org/jira/browse/ARROW-11497
>             Project: Apache Arrow
>          Issue Type: Bug
>          Components: Python
>    Affects Versions: 3.0.0
>            Reporter: Truc Lam Nguyen
>            Priority: Major
>         Attachments: parquet-tools-meta.log
>
>
> Sorry if I don't know this feature is done deliberately, but it looks like the parquet writer for list data type does not confirm to Apache Parquet list logical type specification,
> According to this page: [https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#lists,] list type contains 3 level where the middle level, named {{list}}, must be a repeated group with a single field named _{{element}}_
> However, in the parquet file from pyarrow writer, that single field is named _item_ instead,
> Please find below the example python code that produce a parquet file (I use pandas version 1.2.1 and pyarrow version 3.0.0)
>  
> {code:java}
> import pandas as pd
>  
> df = pd.DataFrame(data=[ {'studio': 'blizzard', 'games': [{'name': 'diablo', 'version': '3'}, {'name': 'star craft', 'version': '2'}]}, {'studio': 'ea', 'games': [{'name': 'fifa', 'version': '21'}]}, ])
> df.to_parquet('/tmp/test.parquet', engine='pyarrow')
> {code}
>  
> Then I use parquet-tools from [https://formulae.brew.sh/formula/parquet-tools] to check the metadata of parquet file via this command
> parquet-tools meta /tmp/test.parquet
> The full meta is included in attached, here is only an extraction of list type column
> games: OPTIONAL F:1 
> .list: REPEATED F:1 
> ..item: OPTIONAL F:2 
> ...name: OPTIONAL BINARY L:STRING R:1 D:4
> ...version: OPTIONAL BINARY L:STRING R:1 D:4
> as can be seen, under list, it is single field named _item_
> I think this should be made to be name _element_ to conform with Apache Parquet specification.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)