cloud-fan commented on a change in pull request #24129: [SPARK-27190][SQL] add table capability for streaming URL: https://github.com/apache/spark/pull/24129#discussion_r276864854
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/V2StreamingScanSupportCheck.scala ########## @@ -0,0 +1,51 @@ +/* + * 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 org.apache.spark.sql.AnalysisException +import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan +import org.apache.spark.sql.execution.streaming.{StreamingRelation, StreamingRelationV2} +import org.apache.spark.sql.sources.v2.TableCapability.{CONTINUOUS_READ, MICRO_BATCH_READ} + +/** + * This rules adds some basic table capability check for streaming scan, without knowing the actual + * streaming execution mode. + */ +object V2StreamingScanSupportCheck extends (LogicalPlan => Unit) { + import DataSourceV2Implicits._ + + override def apply(plan: LogicalPlan): Unit = { Review comment: > Why would this check depend on fallback logic? It's the opposite. The fallback logic depends on the check. That said, the future analyzer rule would do 3 things: 1. find the v2 streaming relation in the plan, check scan capability 2. if check failed, fallback to v1 relation, and use the v1 relation to replace the v2 streaming relation. 3. if fallback is not applicable, fail You can see that, it's not a simple check anymore, which can not be done within this simpler checker rule (`LogicalPlan => Unit`). ---------------------------------------------------------------- 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]
