[GitHub] [arrow] wesm commented on a change in pull request #8811: ARROW-6883: [C++][Python] Allow writing dictionary deltas

[GitBox <gi...@apache.org>]

wesm commented on a change in pull request #8811:
URL: https://github.com/apache/arrow/pull/8811#discussion_r535540948



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File path: cpp/src/arrow/ipc/options.h
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@@ -65,6 +65,20 @@ struct ARROW_EXPORT IpcWriteOptions {
   /// like compression
   bool use_threads = true;
 
+  /// \brief Whether to emit dictionary deltas
+  ///
+  /// If false, a changed dictionary for a given field will emit a full
+  /// dictionary replacement.
+  /// If true, a changed dictionary will be compared against the previous
+  /// version. If possible, a dictionary delta will be omitted, otherwise
+  /// a full dictionary replacement.
+  ///
+  /// Default is false to maximize stream compatibility.

Review comment:
       Might help to be explicit to say that otherwise the order of dictionaries may be altered by a passage from sender to receiver (I assume that's what you mean here by "stream compatibility" but others might be scratching their heads)




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