[FLINK-34503][table] Migrate JoinDeriveNullFilterRule to java

flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/plan/rules/logical/JoinDeriveNullFilterRule.java

@@ -0,0 +1,134 @@
+/*
+ * 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.plan.rules.logical;
+
+import org.apache.flink.table.planner.plan.metadata.FlinkRelMetadataQuery;
+
+import org.apache.flink.shaded.curator5.org.apache.curator.shaded.com.google.common.collect.Lists;
+
+import org.apache.calcite.plan.RelOptRuleCall;
+import org.apache.calcite.plan.RelRule;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.core.Join;
+import org.apache.calcite.rel.core.JoinInfo;
+import org.apache.calcite.rel.core.JoinRelType;
+import org.apache.calcite.rel.logical.LogicalJoin;
+import org.apache.calcite.rex.RexBuilder;
+import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.sql.fun.SqlStdOperatorTable;
+import org.apache.calcite.tools.RelBuilder;
+import org.apache.calcite.util.ImmutableIntList;
+import org.immutables.value.Value;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Planner rule that filters null values before join if the count null value from join input is
+ * greater than null filter threshold.
+ *
+ * <p>Since the key of the Null value is impossible to match in the inner join, and there is a
+ * single point skew due to too many Null values. We should push down a not-null filter into the
+ * child node of join.
+ */
+@Value.Enclosing
+public class JoinDeriveNullFilterRule
+        extends RelRule<JoinDeriveNullFilterRule.JoinDeriveNullFilterRuleConfig> {
+
+    // To avoid the impact of null values on the single join node,
+    // We will add a null filter (possibly be pushed down) before the join to filter
+    // null values when the source of InnerJoin has nullCount more than this value.
+    public static final Long JOIN_NULL_FILTER_THRESHOLD = 2000000L;
+
+    public static final JoinDeriveNullFilterRule INSTANCE =
+            JoinDeriveNullFilterRule.JoinDeriveNullFilterRuleConfig.DEFAULT.toRule();
+
+    private JoinDeriveNullFilterRule(JoinDeriveNullFilterRuleConfig config) {
+        super(config);
+    }
+
+    @Override
+    public boolean matches(RelOptRuleCall call) {
+        Join join = call.rel(0);
+        return join.getJoinType() == JoinRelType.INNER
+                && !join.analyzeCondition().pairs().isEmpty();
+    }
+
+    @Override
+    public void onMatch(RelOptRuleCall call) {
+        LogicalJoin join = call.rel(0);
+
+        RelBuilder relBuilder = call.builder();
+        RexBuilder rexBuilder = join.getCluster().getRexBuilder();
+        FlinkRelMetadataQuery mq =
+                FlinkRelMetadataQuery.reuseOrCreate(join.getCluster().getMetadataQuery());
+
+        JoinInfo joinInfo = join.analyzeCondition();
+        RelNode newLeft =
+                createIsNotNullFilter(
+                        relBuilder, rexBuilder, mq, join.getLeft(), joinInfo.leftKeys);
+        RelNode newRight =
+                createIsNotNullFilter(
+                        relBuilder, rexBuilder, mq, join.getRight(), joinInfo.rightKeys);
+
+        if ((newLeft != join.getLeft()) || (newRight != join.getRight())) {
+            Join newJoin = join.copy(join.getTraitSet(), Lists.newArrayList(newLeft, newRight));
+            call.transformTo(newJoin);
+        }
+    }
+
+    private RelNode createIsNotNullFilter(
+            RelBuilder relBuilder,
+            RexBuilder rexBuilder,
+            FlinkRelMetadataQuery mq,
+            RelNode input,
+            ImmutableIntList keys) {
+        List<RexNode> filters = new ArrayList<>();
+        for (int key : keys) {
+            Double nullCount = mq.getColumnNullCount(input, key);
+            if (nullCount != null && nullCount > JOIN_NULL_FILTER_THRESHOLD) {
+                filters.add(
+                        relBuilder.call(
+                                SqlStdOperatorTable.IS_NOT_NULL,
+                                rexBuilder.makeInputRef(input, key)));
+            }
+        }
+
+        if (!filters.isEmpty()) {
+            return relBuilder.push(input).filter(filters).build();
+        } else {
+            return input;
+        }
+    }
+
+    /** Rule configuration. */
+    @Value.Immutable(singleton = false)
+    public interface JoinDeriveNullFilterRuleConfig extends RelRule.Config {
+        JoinDeriveNullFilterRule.JoinDeriveNullFilterRuleConfig DEFAULT =
+                ImmutableJoinDeriveNullFilterRule.JoinDeriveNullFilterRuleConfig.builder()
+                        .build()
+                        .withOperandSupplier(b0 -> b0.operand(LogicalJoin.class).anyInputs())
+                        .withDescription("JoinDeriveNullFilterRule");
+
+        @Override
+        default JoinDeriveNullFilterRule toRule() {
+            return new JoinDeriveNullFilterRule(this);
+        }
+    }
+}