rdblue commented on a change in pull request #25601: [SPARK-28856][SQL] Implement SHOW DATABASES for Data Source V2 Tables URL: https://github.com/apache/spark/pull/25601#discussion_r319636863
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/ShowDatabasesExec.scala ########## @@ -0,0 +1,62 @@ +/* + * 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.execution.datasources.v2 + +import scala.collection.mutable.ArrayBuffer + +import org.apache.spark.rdd.RDD +import org.apache.spark.sql.catalog.v2.CatalogV2Implicits.NamespaceHelper +import org.apache.spark.sql.catalog.v2.SupportsNamespaces +import org.apache.spark.sql.catalyst.InternalRow +import org.apache.spark.sql.catalyst.encoders.RowEncoder +import org.apache.spark.sql.catalyst.expressions.{Attribute, GenericRowWithSchema} +import org.apache.spark.sql.catalyst.util.StringUtils +import org.apache.spark.sql.execution.LeafExecNode + +/** + * Physical plan node for showing databases. + */ +case class ShowDatabasesExec( + output: Seq[Attribute], + catalog: SupportsNamespaces, + pattern: Option[String]) + extends LeafExecNode { + override protected def doExecute(): RDD[InternalRow] = { + val namespaces = catalog.listNamespaces().flatMap(getNamespaces(catalog, _)) Review comment: Another option is to ignore the current namespace entirely. `SHOW NAMESPACES` would list the root, and `SHOW NAMESPACES IN ns1` lists namespaces in `ns1`. The context is always explicit. I think I would prefer that option. ---------------------------------------------------------------- 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: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
