kou commented on PR #43273:
URL: https://github.com/apache/arrow/pull/43273#issuecomment-2259725541

   > I didn't fully catch the things before, how does this able to react with C 
interface? Does `Statistics` still need to be stored in key-value-metadata?
   
   The "react with C interface" refers the "[DISCUSS] Statistics through the C 
data interface" thread 
https://lists.apache.org/thread/z0jz2bnv61j7c6lbk7lympdrs49f69cx , right?
   
   We will not use metadata for it. We will send an array that uses the 
following schema separately for it:
   
   https://lists.apache.org/thread/8j7sc0lwl3f9c77srpvkt83r43ktwwfr
   
   ```text
   map<
      // The column index or null if the statistics refer to whole table or 
batch.
     column: int32,
     // Statistics key is dictionary<int32, utf8>. Will will provide 
pre-defined key names. Custom key names
     // are also supported.
     // Different keys are assigned for exact value and approximate value.
     map<dictionary<int32, utf8>, dense_union<...needed types based on stat 
kinds in the keys...>
   >
   ```
   
   So we don't store `arrow::Statistics` to metadata. We'll provide a 
convenient function that converts an `arrow::Statistics` to an array that uses 
the schema.


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]

Reply via email to