rdblue commented on a change in pull request #30562:
URL: https://github.com/apache/spark/pull/30562#discussion_r534340700
##########
File path:
sql/catalyst/src/main/java/org/apache/spark/sql/connector/catalog/SupportsDelete.java
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@@ -28,6 +28,25 @@
*/
@Evolving
public interface SupportsDelete {
+
+ /**
+ * Checks whether it is possible to delete data from a data source table
that matches filter
+ * expressions.
+ * <p>
+ * Rows should be deleted from the data source iff all of the filter
expressions match.
+ * That is, the expressions must be interpreted as a set of filters that are
ANDed together.
+ * <p>
+ * Spark will call this method to check if the delete is possible without
significant effort.
Review comment:
> My worry is that we may change the API back and forth if we don't have
a clear big picture. Right now this patch is not useful as it only changes
where we throw the exception, but I can see that this will be useful when we
have the row-level delete API and we can use the canDeleteWhere to decide if we
want to use the row-level API or not.
This is exactly the reason for adding this API. It is a step toward
rewriting plans for row-level DELETE and MERGE operations. The current
`deleteWhere` exception approach happens while running the physical plan, when
it is too late to rewrite the plan for row-level changes. Adding the
`canDeleteWhere` check fixes that problem.
Since you can easily see how it will be used, what is the concern about
adding this?
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