chaoqin-li1123 commented on code in PR #39931: URL: https://github.com/apache/spark/pull/39931#discussion_r1104913618
########## sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/WatermarkPropagator.scala: ########## @@ -0,0 +1,286 @@ +/* + * 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.streaming + +import java.{util => jutil} + +import scala.collection.mutable + +import org.apache.spark.internal.Logging +import org.apache.spark.sql.AnalysisException +import org.apache.spark.sql.execution.SparkPlan +import org.apache.spark.sql.execution.streaming.WatermarkPropagator.DEFAULT_WATERMARK_MS +import org.apache.spark.sql.internal.SQLConf +import org.apache.spark.util.Utils + +/** Interface for propagating watermark. */ +trait WatermarkPropagator { + /** + * Request to propagate watermark among operators based on origin watermark value. The result + * should be input watermark per stateful operator, which Spark will request the value by calling + * getInputWatermarkXXX with operator ID. + * + * It is recommended for implementation to cache the result, as Spark can request the propagation + * multiple times with the same batch ID and origin watermark value. + */ + def propagate(batchId: Long, plan: SparkPlan, originWatermark: Long): Unit Review Comment: It seems that IncrementalExecution planning and purging run sequentially, so there is no need to synchronize the write. Will there be any future use case that access this cache interface concurrently? Should we document this is not thread-safe? -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
