rdblue commented on a change in pull request #24029: SPARK-27108: Add parsed SQL plans for create, CTAS. URL: https://github.com/apache/spark/pull/24029#discussion_r265345063
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/sql/ParsedLogicalPlan.scala ########## @@ -0,0 +1,38 @@ +/* + * 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.catalyst.plans.logical.sql + +import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan + +/** + * A logical plan node that contains exactly what was parsed from SQL. + * + * This is used to hold information parsed from SQL when there are multiple implementations of a + * query or command. For example, CREATE TABLE may be implemented by different nodes for v1 and v2. + * Instead of parsing directly to a v1 CreateTable that keeps metadata in CatalogTable, and then + * converting that v1 metadata to the v2 equivalent, the sql [[CreateTable]] plan is produced by + * the parser and converted once into both implementations. + * + * Parsed logical plans are not resolved because they must be converted to concrete logical plans. Review comment: The value of this class is that it identifies the set of logical plans that correspond directly to what was parsed from SQL. When someone working on a plan sees `ParsedLogicalPlan` as an ancestor in Scaladoc, it signals what is explained here: that parser produces `ParsedLogicalPlan` nodes without translating what was parsed, then those plans get translated into real plans in the analyzer. With that information, it is easy to see what changes need to be made. If the parsed plan doesn't include an option, then the parser and parsed plan needs to be updated. If it does include an option, then the analyzer and downstream plans need to be updated. Also keep in mind that this is the first two subclasses of `ParsedLogicalPlan`. To implement v2 along-side v1, we are going to be adding more of them. So it is valuable that we don't need to remember to set `resolved` to false in every plan. ---------------------------------------------------------------- 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]
