spark EventTimeWatermark 源码
spark EventTimeWatermark 代码
文件路径：/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/EventTimeWatermark.scala
/*
* 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
import java.util.concurrent.TimeUnit
import org.apache.spark.sql.catalyst.expressions.Attribute
import org.apache.spark.sql.catalyst.trees.TreePattern.{EVENT_TIME_WATERMARK, TreePattern}
import org.apache.spark.sql.catalyst.util.IntervalUtils
import org.apache.spark.sql.types.MetadataBuilder
import org.apache.spark.unsafe.types.CalendarInterval
object EventTimeWatermark {
/** The [[org.apache.spark.sql.types.Metadata]] key used to hold the eventTime watermark delay. */
val delayKey = "spark.watermarkDelayMs"
def getDelayMs(delay: CalendarInterval): Long = {
IntervalUtils.getDuration(delay, TimeUnit.MILLISECONDS)
}
}
/**
* Used to mark a user specified column as holding the event time for a row.
*/
case class EventTimeWatermark(
eventTime: Attribute,
delay: CalendarInterval,
child: LogicalPlan) extends UnaryNode {
final override val nodePatterns: Seq[TreePattern] = Seq(EVENT_TIME_WATERMARK)
// Update the metadata on the eventTime column to include the desired delay.
override val output: Seq[Attribute] = child.output.map { a =>
if (a semanticEquals eventTime) {
val delayMs = EventTimeWatermark.getDelayMs(delay)
val updatedMetadata = new MetadataBuilder()
.withMetadata(a.metadata)
.putLong(EventTimeWatermark.delayKey, delayMs)
.build()
a.withMetadata(updatedMetadata)
} else if (a.metadata.contains(EventTimeWatermark.delayKey)) {
// Remove existing watermark
val updatedMetadata = new MetadataBuilder()
.withMetadata(a.metadata)
.remove(EventTimeWatermark.delayKey)
.build()
a.withMetadata(updatedMetadata)
} else {
a
}
}
override protected def withNewChildInternal(newChild: LogicalPlan): EventTimeWatermark =
copy(child = newChild)
}
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