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Posted to issues@hive.apache.org by "Kokila N (Jira)" <ji...@apache.org> on 2026/04/30 05:20:00 UTC
[jira] [Resolved] (HIVE-29458) Z-order and custom sort expressions in WRITE LOCALLY ORDERED BY cause data scatter across reducers due to hash distribution
[ https://issues.apache.org/jira/browse/HIVE-29458?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Kokila N resolved HIVE-29458.
-----------------------------
Fix Version/s: 4.3.0
Resolution: Fixed
> Z-order and custom sort expressions in WRITE LOCALLY ORDERED BY cause data scatter across reducers due to hash distribution
> ---------------------------------------------------------------------------------------------------------------------------
>
> Key: HIVE-29458
> URL: https://issues.apache.org/jira/browse/HIVE-29458
> Project: Hive
> Issue Type: Bug
> Reporter: Kokila N
> Assignee: Kokila N
> Priority: Major
> Labels: pull-request-available
> Fix For: 4.3.0
>
>
> *Problem*
> When using
> {code:java}
> `WRITE LOCALLY ORDERED BY zorder()`{code}
> or other custom sort expressions on Iceberg tables, the sort expressions are added to the ReduceSink partition columns (distribution keys). This causes data to be scattered across reducers based on `hash(partition_col, sort_expr) % num_reducers`.
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