[GitHub] [flink] lincoln-lil commented on a diff in pull request #21219: [FLINK-29849][table-planner] Fix event time temporal join on an upsert source may produce incorrect execution plan

[GitBox <gi...@apache.org>]

lincoln-lil commented on code in PR #21219:
URL: https://github.com/apache/flink/pull/21219#discussion_r1018704994


##########
flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/calcite/FlinkSnapshotConverter.java:
##########
@@ -0,0 +1,95 @@
+/*
+ * 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.flink.table.planner.calcite;
+
+import org.apache.flink.table.planner.plan.nodes.logical.FlinkLogicalCalc;
+import org.apache.flink.table.planner.plan.nodes.logical.FlinkLogicalSnapshot;
+import org.apache.flink.table.planner.plan.nodes.logical.FlinkLogicalTableSourceScan;
+import org.apache.flink.table.planner.plan.nodes.logical.FlinkLogicalWatermarkAssigner;
+import org.apache.flink.table.planner.plan.schema.TimeIndicatorRelDataType;
+
+import org.apache.calcite.rel.RelHomogeneousShuttle;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.type.RelDataType;
+
+/**
+ * Traverses a {@link RelNode} tree and update the child node of {@link FlinkLogicalSnapshot} to set
+ * {@link FlinkLogicalTableSourceScan#eventTimeSnapshot} property.
+ *
+ * <p>Note: only snapshot on event time period will update the child {@link
+ * FlinkLogicalTableSourceScan}.
+ */
+public final class FlinkSnapshotConverter extends RelHomogeneousShuttle {
+
+    public static RelNode update(RelNode input) {
+        FlinkSnapshotConverter converter = new FlinkSnapshotConverter();
+        return input.accept(converter);
+    }
+
+    @Override
+    public RelNode visit(RelNode node) {
+        if (node instanceof FlinkLogicalSnapshot) {
+            final FlinkLogicalSnapshot snapshot = (FlinkLogicalSnapshot) node;
+            if (isEventTime(snapshot.getPeriod().getType())) {
+                final RelNode child = snapshot.getInput();
+                final RelNode newChild = transmitSnapshotRequirement(child);
+                if (newChild != child) {
+                    return snapshot.copy(snapshot.getTraitSet(), newChild, snapshot.getPeriod());
+                }
+            }
+            return snapshot;
+        }
+        return super.visit(node);
+    }
+
+    private boolean isEventTime(RelDataType period) {
+        if (period instanceof TimeIndicatorRelDataType) {
+            return ((TimeIndicatorRelDataType) period).isEventTime();
+        }
+        return false;
+    }
+
+    private RelNode transmitSnapshotRequirement(RelNode node) {
+        if (node instanceof FlinkLogicalCalc) {
+            final FlinkLogicalCalc calc = (FlinkLogicalCalc) node;
+            final RelNode child = calc.getInput();
+            final RelNode newChild = transmitSnapshotRequirement(child);
+            if (newChild != child) {
+                return calc.copy(calc.getTraitSet(), newChild, calc.getProgram());
+            }
+            return calc;
+        }
+        if (node instanceof FlinkLogicalWatermarkAssigner) {
+            final FlinkLogicalWatermarkAssigner wma = (FlinkLogicalWatermarkAssigner) node;
+            final RelNode child = wma.getInput();
+            final RelNode newChild = transmitSnapshotRequirement(child);

Review Comment:
   Good question! For my understanding though there's no strict rule for the implementations, but the shuttle utils are always the first choice(please correct me if I'm wrong, maybe @godfreyhe can give more guidance here). Back to this pr, the recursion is for the requirement transmition, and I didn't spent too much time to extend a shuttle to pass the requirement flag for visiting nodes(intuitively, the code will expand a lot), so I assume it's a reasonable choice for the specific issue here. Wish this can help explain your question.



##########
flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/plan/rules/logical/FlinkFilterJoinRule.java:
##########
@@ -449,6 +455,33 @@ protected FlinkFilterIntoJoinRule(FlinkFilterIntoJoinRule.Config config) {
             super(config);
         }
 
+        @Override
+        public boolean matches(RelOptRuleCall call) {
+            Join join = call.rel(1);
+            return !isEventTimeTemporalJoin(join.getCondition()) && super.matches(call);
+        }

Review Comment:
   This is mainly for the long term goal of 'planner scala free'(so didn't change the private method TemporalJoinUtil#containsTemporalJoinCondition), but without adding a java util for this single method, we can add that util if more callers need this utility method or we want to refactor the 
    TemporalJoinUtil from scala to java, WDYT?



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