See https://github.com/apache/arrow/pull/10860#discussion_r682554824 **Reporter**: [Yibo Cai](https://issues.apache.org/jira/browse/ARROW-13631) / @cyb70289 **Assignee**: [Yibo Cai](https://issues.apache.org/jira/browse/ARROW-13631) / @cyb70289 #### Related issues: - [[C++] Add TDigest::Merge(const TDigest&)](https://github.com/apache/arrow/issues/29318) (duplicates) <sub>**Note**: *This issue was originally created as [ARROW-13631](https://issues.apache.org/jira/browse/ARROW-13631). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*</sub>