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Posted to github@arrow.apache.org by "Morgan279 (via GitHub)" <gi...@apache.org> on 2024/11/29 09:20:29 UTC

[PR] change map field default names to follow the parquet format spec [arrow-rs]

Morgan279 opened a new pull request, #6814:
URL: https://github.com/apache/arrow-rs/pull/6814

   # Which issue does this PR close?
   
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   Closes [#6213 ](https://github.com/apache/arrow-rs/issues/6213) .
   
   # Rationale for this change
   The MapBuilder uses the nonstandardized default names, which results in [#6213 ](https://github.com/apache/arrow-rs/issues/6213). Changing to parquet spec helps reduce confusion and provides users with a more standardized naming guide.
   
   [According to the parquet-format spec](https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#backward-compatibility-rules-1), the outer-most level should be a group that contains a single field named **key_value** for Map type:
   > The outer-most level must be a group annotated with MAP that contains a single field named **key_value**. The repetition of this level must be either optional or required and determines whether the map is nullable.
   The middle level, named key_value, must be a repeated group with a **key** field for map keys and, optionally, a **value** field for map values. It must not contain any other values.
   
   
   Changing the default map field names to match it not only complies with the parquet spec, but also aligns with pyarrow.
    
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   # What changes are included in this PR?
   Default value of the MapFieldNames
   
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   # Are there any user-facing changes?
   No(I think)
   
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Re: [PR] change map field default names to follow the parquet format spec [arrow-rs]

Posted by "tustvold (via GitHub)" <gi...@apache.org>.
tustvold commented on PR #6814:
URL: https://github.com/apache/arrow-rs/pull/6814#issuecomment-2507642080

   Can you confirm pyarrow does follow this convention, the arrow spec has different guidance
   
   https://github.com/apache/arrow-rs/blob/main/format%2FSchema.fbs#L133
   
   I'm also rather wary of making this change as it will be highly disruptive, and for relatively limited benefit


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Re: [PR] change map field default names to follow the parquet format spec [arrow-rs]

Posted by "Morgan279 (via GitHub)" <gi...@apache.org>.
Morgan279 closed pull request #6814: change map field default names to follow the parquet format spec
URL: https://github.com/apache/arrow-rs/pull/6814


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