miland-db commented on code in PR #53508:
URL: https://github.com/apache/spark/pull/53508#discussion_r2635678161
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sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/rules.scala:
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@@ -695,19 +695,43 @@ 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 newMetadata = viewFieldsByName.get(planField.name) match {
+ case Some(viewField) =>
+ // Use table metadata but override with view comment
+ val builder = new
MetadataBuilder().withMetadata(planField.metadata)
+ viewField.getComment() match {
+ case Some(comment) => builder.putString("comment", comment)
+ case None => builder.remove("comment")
Review Comment:
On view creation comments will be inherited from the table. After that, the
comments will either keep that value or get the new value set by user. So if
user doesn't do anything related to comments, comments will just stay the same
as they were during view creation.
If everything is the same, **redo** will not even be triggered on `SELECT`.
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