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https://issues.apache.org/jira/browse/HIVE-25975?focusedWorklogId=734758&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-734758
 ]

ASF GitHub Bot logged work on HIVE-25975:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 01/Mar/22 16:41
            Start Date: 01/Mar/22 16:41
    Worklog Time Spent: 10m 
      Work Description: marton-bod commented on a change in pull request #3060:
URL: https://github.com/apache/hive/pull/3060#discussion_r816948553



##########
File path: ql/src/java/org/apache/hadoop/hive/ql/plan/DynamicPartitionCtx.java
##########
@@ -50,6 +52,14 @@
   private String defaultPartName; // default partition name in case of null or 
empty value
   private int maxPartsPerNode;    // maximum dynamic partitions created per 
mapper/reducer
   private Pattern whiteListPattern;
+  /**
+   * Expressions describing a custom way of sorting the table before write. 
Expressions can reference simple
+   * column descriptions or a tree of expressions containing more columns and 
UDFs.
+   * Can be useful for custom bucket/hash sorting.
+   * A custom expression should be a lambda that is given the original column 
description expressions as per read
+   * schema and returns a single expression. Example for simply just 
referencing column 3: cols -> cols.get(3).clone()
+   */
+  private transient List<Function<List<ExprNodeDesc>, ExprNodeDesc>> 
customSortExpressions;

Review comment:
       Yeah, I was wondering if it's okay if these expressions don't get to the 
executors. But I got my answer - Thanks!




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Issue Time Tracking
-------------------

    Worklog Id:     (was: 734758)
    Time Spent: 4h  (was: 3h 50m)

> Optimize ClusteredWriter for bucketed Iceberg tables
> ----------------------------------------------------
>
>                 Key: HIVE-25975
>                 URL: https://issues.apache.org/jira/browse/HIVE-25975
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Ádám Szita
>            Assignee: Ádám Szita
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 4h
>  Remaining Estimate: 0h
>
> The first version of the ClusteredWriter in Hive-Iceberg will be lenient for 
> bucketed tables: i.e. the records do not need to be ordered by the bucket 
> values, the writer will just close its current file and open a new one for 
> out-of-order records. 
> This is suboptimal for the long-term due to creating many small files. Spark 
> uses a UDF to compute the bucket value for each record and therefore it is 
> able to order the records by bucket values, achieving optimal clustering.



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