[jira] [Updated] (ARROW-13467) [C++] Support delta dictionaries in the IPC file format

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-13467?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ASF GitHub Bot updated ARROW-13467:
-----------------------------------
    Labels: pull-request-available  (was: )

> [C++] Support delta dictionaries in the IPC file format
> -------------------------------------------------------
>
>                 Key: ARROW-13467
>                 URL: https://issues.apache.org/jira/browse/ARROW-13467
>             Project: Apache Arrow
>          Issue Type: Improvement
>          Components: C++
>            Reporter: Weston Pace
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> The spec states:
> > In the file format, there is no requirement that dictionary keys should be defined in a
> > {{DictionaryBatch}} before they are used in a {{RecordBatch}}, as long as the keys are
> > defined somewhere in the file. Further more, it is invalid to have more than one *non-delta*
> > dictionary batch per dictionary ID (i.e. dictionary replacement is not supported). Delta
> > dictionaries are applied in the order they appear in the file footer.
> This seems to suggest that dictionary deltas (but not replacements) are allowed.  However, both reading and writing an IPC file with a dictionary delta fails.



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