Github user brkyvz commented on a diff in the pull request:
https://github.com/apache/spark/pull/19271#discussion_r139814268
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StreamingSymmetricHashJoinExecHelper.scala
---
@@ -0,0 +1,303 @@
+/*
+ * 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 scala.util.control.NonFatal
+
+import org.apache.spark.internal.Logging
+import org.apache.spark.sql.catalyst.expressions.{Add, Attribute,
AttributeReference, BoundReference, Cast, CheckOverflow, Expression,
ExpressionSet, GreaterThan, GreaterThanOrEqual, LessThan, LessThanOrEqual,
Literal, Multiply, NamedExpression, PredicateHelper, Subtract, TimeAdd,
TimeSub, UnaryMinus}
+import org.apache.spark.sql.catalyst.plans.logical.EventTimeWatermark._
+import
org.apache.spark.sql.execution.streaming.WatermarkSupport.watermarkExpression
+import org.apache.spark.sql.types._
+import org.apache.spark.unsafe.types.CalendarInterval
+
+
+/**
+ * Helper object for [[StreamingSymmetricHashJoinExec]].
+ */
+object StreamingSymmetricHashJoinExecHelper extends PredicateHelper with
Logging {
+
+ sealed trait JoinSide
+ case object LeftSide extends JoinSide { override def toString(): String
= "left" }
+ case object RightSide extends JoinSide { override def toString(): String
= "right" }
+
+ sealed trait JoinStateWatermarkPredicate
+ case class JoinStateKeyWatermarkPredicate(expr: Expression) extends
JoinStateWatermarkPredicate
+ case class JoinStateValueWatermarkPredicate(expr: Expression) extends
JoinStateWatermarkPredicate
+
+ case class JoinStateWatermarkPredicates(
+ left: Option[JoinStateWatermarkPredicate] = None,
+ right: Option[JoinStateWatermarkPredicate] = None)
+
+ def getStateWatermarkPredicates(
+ leftAttributes: Seq[Attribute],
+ rightAttributes: Seq[Attribute],
+ leftKeys: Seq[Expression],
+ rightKeys: Seq[Expression],
+ condition: Option[Expression],
+ eventTimeWatermark: Option[Long]): JoinStateWatermarkPredicates = {
+ val joinKeyOrdinalForWatermark: Option[Int] = {
+ leftKeys.zipWithIndex.collectFirst {
+ case (ne: NamedExpression, index) if
ne.metadata.contains(delayKey) => index
+ } orElse {
+ rightKeys.zipWithIndex.collectFirst {
+ case (ne: NamedExpression, index) if
ne.metadata.contains(delayKey) => index
+ }
+ }
+ }
+
+ def getOneSideStateWatermarkPredicate(
+ oneSideInputAttributes: Seq[Attribute],
+ oneSideJoinKeys: Seq[Expression],
+ otherSideInputAttributes: Seq[Attribute]):
Option[JoinStateWatermarkPredicate] = {
+ val isWatermarkDefinedOnInput =
oneSideInputAttributes.exists(_.metadata.contains(delayKey))
+ val isWatermarkDefinedOnJoinKey =
joinKeyOrdinalForWatermark.isDefined
+
+ if (isWatermarkDefinedOnJoinKey) { // case 1 and 3 explained in the
class docs
+ val keyExprWithWatermark = BoundReference(
+ joinKeyOrdinalForWatermark.get,
+ oneSideJoinKeys(joinKeyOrdinalForWatermark.get).dataType,
+ oneSideJoinKeys(joinKeyOrdinalForWatermark.get).nullable)
+ val expr = watermarkExpression(Some(keyExprWithWatermark),
eventTimeWatermark)
+ expr.map(JoinStateKeyWatermarkPredicate)
+
+ } else if (isWatermarkDefinedOnInput) { // case 2 explained in the
class docs
+ val stateValueWatermark = getStateValueWatermark(
+ attributesToFindStateWatemarkFor = oneSideInputAttributes,
+ attributesWithEventWatermark = otherSideInputAttributes,
+ condition,
+ eventTimeWatermark)
+ val inputAttributeWithWatermark =
oneSideInputAttributes.find(_.metadata.contains(delayKey))
+ val expr = watermarkExpression(inputAttributeWithWatermark,
stateValueWatermark)
+ expr.map(JoinStateValueWatermarkPredicate)
+
+ } else {
+ None
+
+ }
+ }
+
+ val leftStateWatermarkPredicate =
+ getOneSideStateWatermarkPredicate(leftAttributes, leftKeys,
rightAttributes)
+ val rightStateWatermarkPredicate =
+ getOneSideStateWatermarkPredicate(rightAttributes, rightKeys,
leftAttributes)
+ JoinStateWatermarkPredicates(leftStateWatermarkPredicate,
rightStateWatermarkPredicate)
+ }
+
+ /**
+ * Get state value watermark (see [[StreamingSymmetricHashJoinExec]] for
context about it)
+ * given the join condition and the event time watermark. This is how it
works.
+ * - The condition is split into conjunctive predicates, and we find the
predicates of the
+ * form `leftTime + c1 < rightTime + c2` (or <=, >, >=).
+ * - We canoncalize the predicate and solve it with the event time
watermark value to find the
+ * value of the state watermark.
+ *
+ * @param attributesToFindStateWatemarkFor attributes of the side whose
state watermark
+ * is to be calculated
+ * @param attributesWithEventWatermark attributes of the other side
which has a watermark column
+ * @param joinCondition join condition
+ * @param eventWatermark watermark defined on the input
event data
+ * @return state value watermark in milliseconds
+ */
+ def getStateValueWatermark(
+ attributesToFindStateWatemarkFor: Seq[Attribute],
+ attributesWithEventWatermark: Seq[Attribute],
+ joinCondition: Option[Expression],
+ eventWatermark: Option[Long]): Option[Long] = {
+ if (joinCondition.isEmpty || eventWatermark.isEmpty) return None
+
+ def getStateWatermarkSafely(l: Expression, r: Expression):
Option[Long] = {
+ try {
+ getStateWatemarkFromLessThenPredicate(
+ l, r, attributesToFindStateWatemarkFor,
attributesWithEventWatermark, eventWatermark)
+ } catch {
+ case NonFatal(e) =>
+ logWarning(s"Error trying to extract state constraint from
condition $joinCondition", e)
+ None
+ }
+ }
+
+ val allStateWatermarks =
splitConjunctivePredicates(joinCondition.get).flatMap { predicate =>
+ val stateWatermark = predicate match {
+ case LessThan(l, r) => getStateWatermarkSafely(l, r)
+ case LessThanOrEqual(l, r) => getStateWatermarkSafely(l, r).map(_
- 1)
+ case GreaterThan(l, r) => getStateWatermarkSafely(r, l)
+ case GreaterThanOrEqual(l, r) => getStateWatermarkSafely(r,
l).map(_ - 1)
--- End diff --
if the above line is `-1`, then I would have assumed this should be `+1`
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