miland-db commented on code in PR #53508:
URL: https://github.com/apache/spark/pull/53508#discussion_r2629165525


##########
sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/rules.scala:
##########
@@ -695,19 +695,36 @@ object ViewSyncSchemaToMetaStore extends (LogicalPlan => 
Unit) {
           (field.dataType != planField.dataType ||
             field.nullable != planField.nullable ||
             (viewSchemaMode == SchemaEvolution && (
-              field.getComment() != planField.getComment() ||
-              field.name != planField.name)))
+              field.name != planField.name ||
+                // Only trigger redo on comment changes if preserve flag is 
disabled.
+                
(!session.sessionState.conf.viewSchemaEvolutionPreserveUserComments &&
+                  field.getComment() != planField.getComment()))))
         }
 
+        lazy val viewFieldsByName = viewFields.map(f => f.name -> f).toMap
+
         if (redo) {
           val newSchema = if (viewSchemaMode == SchemaTypeEvolution) {
             val newFields = viewQuery.schema.map {
               case StructField(name, dataType, nullable, _) =>
                 StructField(name, dataType, nullable,
-                  viewFields.find(_.name == name).get.metadata)
+                  viewFieldsByName(name).metadata)
+            }
+            StructType(newFields)
+          } else if 
(session.sessionState.conf.viewSchemaEvolutionPreserveUserComments) {
+            // Adopt types/nullable/names from query, but preserve view 
comments.
+            val newFields = viewQuery.schema.map { planField =>
+              val metadataToUse = viewFieldsByName.get(planField.name) match {
+                case Some(viewField) =>
+                  viewField.metadata
+                case None =>
+                  planField.metadata

Review Comment:
   What if the column name was changed?



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]


---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to