Github user jiangxb1987 commented on a diff in the pull request:
https://github.com/apache/spark/pull/16233#discussion_r95422458
--- Diff:
sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveMetastoreCatalog.scala ---
@@ -125,11 +132,16 @@ private[hive] class
HiveMetastoreCatalog(sparkSession: SparkSession) extends Log
// Otherwise, wrap the table with a Subquery using the table name.
alias.map(a => SubqueryAlias(a, qualifiedTable,
None)).getOrElse(qualifiedTable)
} else if (table.tableType == CatalogTableType.VIEW) {
+ val tableIdentifier = table.identifier
val viewText = table.viewText.getOrElse(sys.error("Invalid view
without text."))
- SubqueryAlias(
- alias.getOrElse(table.identifier.table),
- sparkSession.sessionState.sqlParser.parsePlan(viewText),
- Option(table.identifier))
+ // The relation is a view, so we wrap the relation by:
+ // 1. Add a [[View]] operator over the relation to keep track of the
view desc;
+ // 2. Wrap the logical plan in a [[SubqueryAlias]] which tracks the
name of the view.
+ val child = View(
+ desc = table,
+ output = table.schema.toAttributes,
+ child = sparkSession.sessionState.sqlParser.parsePlan(viewText))
--- End diff --
It may looks a little over-engineering for now, but that enables us to
decouple planning of query from the planning of the view, which allows us to
cache resolved views in the future, and decoupling also allows you to deal with
some forms of schema evolution (moving column order or columns being added to
underlying data).
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