[GitHub] [spark] rdblue commented on a change in pull request #31355: [SPARK-34255][SQL] Support partitioning with static number on required distribution and ordering on V2 write

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

rdblue commented on a change in pull request #31355:
URL: https://github.com/apache/spark/pull/31355#discussion_r565733924



##########
File path: sql/catalyst/src/main/java/org/apache/spark/sql/connector/distributions/ClusteredDistribution.java
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@@ -32,4 +32,13 @@
    * Returns clustering expressions.
    */
   Expression[] clustering();
+
+  /**
+   * Returns the number of partitions required by this write.
+   * <p>
+   * Implementations may want to override this if it requires the specific number of partitions.
+   *
+   * @return the required number of partitions, non-positive values mean no requirement.
+   */
+  default int requiredNumPartitions() { return 0; }

Review comment:
       Why not also add a parallelism requirement to `UnspecifiedDistribution`? That could insert a coalesce.




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