huaxingao commented on a change in pull request #29396: URL: https://github.com/apache/spark/pull/29396#discussion_r482597501
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/jdbc/JDBCWriteBuilder.scala ########## @@ -0,0 +1,46 @@ +/* + * 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.jdbc + +import org.apache.spark.sql._ +import org.apache.spark.sql.connector.write._ +import org.apache.spark.sql.execution.datasources.jdbc.{JdbcOptionsInWrite, JdbcUtils} +import org.apache.spark.sql.internal.SQLConf +import org.apache.spark.sql.sources.InsertableRelation +import org.apache.spark.sql.types.StructType + +case class JDBCWriteBuilder(schema: StructType, options: JdbcOptionsInWrite) extends V1WriteBuilder + with SupportsTruncate { + + private var isTruncate = false + + override def truncate(): WriteBuilder = { + isTruncate = true + this + } + + override def buildForV1Write(): InsertableRelation = new InsertableRelation { + override def insert(data: DataFrame, overwrite: Boolean): Unit = { + // TODO (SPARK-32595): do truncate and append atomically. Review comment: @cloud-fan I have a question here: I think it makes sense to do truncate and append atomically. However, in `JDBCRelationProvider.createRelation`, it doesn't do `truncateTable` and `saveTable` atomically, or `dropTable`, `createTable`, and `saveTable` atomically. ``` case SaveMode.Overwrite => if (options.isTruncate && isCascadingTruncateTable(options.url) == Some(false)) { // In this case, we should truncate table and then load. truncateTable(conn, options) val tableSchema = JdbcUtils.getSchemaOption(conn, options) saveTable(df, tableSchema, isCaseSensitive, conn, options) } else { // Otherwise, do not truncate the table, instead drop and recreate it dropTable(conn, options.table, options) createTable(conn, options.table, df.schema, isCaseSensitive, options) saveTable(df, Some(df.schema), isCaseSensitive, conn, options) } ``` Do we want to be consistent with the old behavior and don't consider atomic or we want to have atomic behavior for both v1 and v2? ---------------------------------------------------------------- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
