[GitHub] [spark] RussellSpitzer commented on a change in pull request #24246: [SPARK-24252][SQL] Add TableCatalog API (WIP)

[GitBox <gi...@apache.org>]

RussellSpitzer commented on a change in pull request #24246: [SPARK-24252][SQL] Add TableCatalog API (WIP)
URL: https://github.com/apache/spark/pull/24246#discussion_r272188028
 
 

 ##########
 File path: sql/catalyst/src/main/java/org/apache/spark/sql/catalog/v2/TableCatalog.java
 ##########
 @@ -0,0 +1,143 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.catalog.v2;
+
+import org.apache.spark.sql.catalog.v2.expressions.Transform;
+import org.apache.spark.sql.catalyst.analysis.NoSuchTableException;
+import org.apache.spark.sql.catalyst.analysis.TableAlreadyExistsException;
+import org.apache.spark.sql.types.StructType;
+
+import java.util.Collections;
+import java.util.Map;
+
+/**
+ * Catalog methods for working with Tables.
+ */
+public interface TableCatalog extends CatalogPlugin {
+  /**
+   * List the tables in a namespace from the catalog.
+   *
+   * @param namespace a multi-part namespace
+   * @return an array of Identifiers for tables
+   */
+  Identifier[] listTables(String[] namespace);
+
+  /**
+   * Load table metadata by {@link Identifier identifier} from the catalog.
+   *
+   * @param ident a table identifier
+   * @return the table's metadata
+   * @throws NoSuchTableException If the table doesn't exist.
+   */
+  Table loadTable(Identifier ident) throws NoSuchTableException;
+
+  /**
+   * Refresh table metadata for {@link Identifier identifier}.
+   * <p>
+   * If the table is already loaded or cached, drop cached data and reload it. If the table is not
 
 Review comment:
   Not sure if this is in the scope of this PR, but I was wondering if we could make the metadata/schema for a table un cacheable by default. For example, in the current V1 code if I reference a relation in the Hive catalog the session will cache the metadata associated with the table. This means that I can't update a user's view of the in catalog table without a manual user refresh. 
   
   I was hoping we can signal via the catalog api that a table's metadata is dynamic and should not be cached.

----------------------------------------------------------------
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.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services

---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org
For additional commands, e-mail: reviews-help@spark.apache.org