Github user cloud-fan commented on a diff in the pull request:
https://github.com/apache/spark/pull/16626#discussion_r107048698
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/catalog/SessionCatalog.scala
---
@@ -296,6 +311,51 @@ class SessionCatalog(
}
/**
+ * Alter the schema of a table identified by the provided table
identifier. The new schema
+ * should still contain the existing bucket columns and partition
columns used by the table. This
+ * method will also update any Spark SQL-related parameters stored as
Hive table properties (such
+ * as the schema itself).
+ *
+ * @param identifier TableIdentifier
+ * @param newSchema Updated schema to be used for the table (must
contain existing partition and
+ * bucket columns)
+ */
+ def alterTableSchema(
+ identifier: TableIdentifier,
+ newSchema: StructType): Unit = {
+ val db =
formatDatabaseName(identifier.database.getOrElse(getCurrentDatabase))
+ val table = formatTableName(identifier.table)
+ val tableIdentifier = TableIdentifier(table, Some(db))
+ requireDbExists(db)
+ requireTableExists(tableIdentifier)
+ checkDuplication(newSchema)
+
+ val catalogTable = externalCatalog.getTable(db, table)
+ val oldSchema = catalogTable.schema
+
+ // not supporting dropping columns yet
+ val nonExistentColumnNames =
oldSchema.map(_.name).filterNot(columnNameResolved(newSchema, _))
+ if (nonExistentColumnNames.nonEmpty) {
+ throw new AnalysisException(
+ s"""
+ |Some existing schema fields
(${nonExistentColumnNames.mkString("[", ",", "]")}) are
+ |not present in the new schema. We don't support dropping
columns yet.
+ """.stripMargin)
+ }
+
+ // make sure partition columns are at the end
+ val partitionSchema = catalogTable.partitionSchema
--- End diff --
`CatalogTable.partitionSchema` will throw exception if partition columns
are not at the end, so we can just call `partitionSchema`, no need to do the
reordering.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
