[GitHub] [flink] SteNicholas commented on a diff in pull request #18408: [FLINK-24865][CEP] Support MATCH_RECOGNIZE in Batch mode

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

SteNicholas commented on code in PR #18408:
URL: https://github.com/apache/flink/pull/18408#discussion_r889804433


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flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/plan/nodes/exec/common/CommonExecMatch.java:
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@@ -0,0 +1,440 @@
+/*
+ * 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.nodes.exec.common;
+
+import org.apache.flink.annotation.VisibleForTesting;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.dag.Transformation;
+import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.cep.EventComparator;
+import org.apache.flink.cep.nfa.aftermatch.AfterMatchSkipStrategy;
+import org.apache.flink.cep.nfa.compiler.NFACompiler;
+import org.apache.flink.cep.operator.CepOperator;
+import org.apache.flink.cep.pattern.Pattern;
+import org.apache.flink.cep.pattern.Quantifier;
+import org.apache.flink.cep.pattern.conditions.BooleanConditions;
+import org.apache.flink.cep.pattern.conditions.IterativeCondition;
+import org.apache.flink.configuration.ReadableConfig;
+import org.apache.flink.streaming.api.transformations.OneInputTransformation;
+import org.apache.flink.streaming.api.windowing.time.Time;
+import org.apache.flink.table.api.TableException;
+import org.apache.flink.table.data.RowData;
+import org.apache.flink.table.planner.codegen.CodeGenUtils;
+import org.apache.flink.table.planner.codegen.CodeGeneratorContext;
+import org.apache.flink.table.planner.codegen.MatchCodeGenerator;
+import org.apache.flink.table.planner.codegen.sort.ComparatorCodeGenerator;
+import org.apache.flink.table.planner.delegation.PlannerBase;
+import org.apache.flink.table.planner.plan.nodes.exec.ExecEdge;
+import org.apache.flink.table.planner.plan.nodes.exec.ExecNode;
+import org.apache.flink.table.planner.plan.nodes.exec.ExecNodeBase;
+import org.apache.flink.table.planner.plan.nodes.exec.ExecNodeConfig;
+import org.apache.flink.table.planner.plan.nodes.exec.ExecNodeContext;
+import org.apache.flink.table.planner.plan.nodes.exec.InputProperty;
+import org.apache.flink.table.planner.plan.nodes.exec.MultipleTransformationTranslator;
+import org.apache.flink.table.planner.plan.nodes.exec.batch.BatchExecMatch;
+import org.apache.flink.table.planner.plan.nodes.exec.spec.MatchSpec;
+import org.apache.flink.table.planner.plan.nodes.exec.spec.SortSpec;
+import org.apache.flink.table.planner.plan.nodes.exec.utils.ExecNodeUtil;
+import org.apache.flink.table.planner.plan.utils.KeySelectorUtil;
+import org.apache.flink.table.planner.plan.utils.RexDefaultVisitor;
+import org.apache.flink.table.planner.utils.JavaScalaConversionUtil;
+import org.apache.flink.table.runtime.generated.GeneratedRecordComparator;
+import org.apache.flink.table.runtime.keyselector.RowDataKeySelector;
+import org.apache.flink.table.runtime.operators.match.PatternProcessFunctionRunner;
+import org.apache.flink.table.runtime.operators.match.RowDataEventComparator;
+import org.apache.flink.table.runtime.typeutils.InternalTypeInfo;
+import org.apache.flink.table.types.logical.LogicalType;
+import org.apache.flink.table.types.logical.RowType;
+import org.apache.flink.util.MathUtils;
+
+import org.apache.calcite.rex.RexCall;
+import org.apache.calcite.rex.RexLiteral;
+import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.sql.SqlMatchRecognize;
+import org.apache.calcite.sql.SqlOperator;
+import org.apache.calcite.sql.fun.SqlStdOperatorTable;
+import org.apache.calcite.sql.type.SqlTypeFamily;
+import org.apache.calcite.tools.RelBuilder;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Optional;
+
+import static org.apache.flink.util.Preconditions.checkArgument;
+import static org.apache.flink.util.Preconditions.checkNotNull;
+
+/** Common {@link ExecNode} which matches along with MATCH_RECOGNIZE. */
+public class CommonExecMatch extends ExecNodeBase<RowData>
+        implements ExecNode<RowData>, MultipleTransformationTranslator<RowData> {
+
+    public static final String MATCH_TRANSFORMATION = "match";
+
+    private final MatchSpec matchSpec;
+
+    public CommonExecMatch(
+            ReadableConfig tableConfig,
+            MatchSpec matchSpec,
+            InputProperty inputProperty,
+            RowType outputType,
+            String description) {
+        this(
+                ExecNodeContext.newNodeId(),
+                ExecNodeContext.newContext(BatchExecMatch.class),
+                ExecNodeContext.newPersistedConfig(BatchExecMatch.class, tableConfig),
+                matchSpec,
+                Collections.singletonList(inputProperty),
+                outputType,
+                description);
+    }
+
+    public CommonExecMatch(
+            int id,
+            ExecNodeContext context,
+            ReadableConfig persistedConfig,
+            MatchSpec matchSpec,
+            List<InputProperty> inputProperties,
+            LogicalType outputType,
+            String description) {
+        super(id, context, persistedConfig, inputProperties, outputType, description);
+        checkArgument(inputProperties.size() == 1);
+        this.matchSpec = checkNotNull(matchSpec);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    protected Transformation<RowData> translateToPlanInternal(
+            PlannerBase planner, ExecNodeConfig config) {
+        final ExecEdge inputEdge = getInputEdges().get(0);
+        final Transformation<RowData> inputTransform =
+                (Transformation<RowData>) inputEdge.translateToPlan(planner);
+        final RowType inputRowType = (RowType) inputEdge.getOutputType();
+
+        checkOrderKeys(inputRowType);
+        final EventComparator<RowData> eventComparator =
+                createEventComparator(config, inputRowType);
+        final Transformation<RowData> timestampedInputTransform =
+                translateOrder(inputTransform, inputRowType, config);
+
+        final Tuple2<Pattern<RowData, RowData>, List<String>> cepPatternAndNames =
+                translatePattern(matchSpec, config, planner.createRelBuilder(), inputRowType);
+        final Pattern<RowData, RowData> cepPattern = cepPatternAndNames.f0;
+
+        // TODO remove this once it is supported in CEP library
+        if (NFACompiler.canProduceEmptyMatches(cepPattern)) {
+            throw new TableException(
+                    "Patterns that can produce empty matches are not supported. There must be at least one non-optional state.");
+        }
+
+        // TODO remove this once it is supported in CEP library
+        if (cepPattern.getQuantifier().hasProperty(Quantifier.QuantifierProperty.GREEDY)) {
+            throw new TableException(
+                    "Greedy quantifiers are not allowed as the last element of a Pattern yet. "
+                            + "Finish your pattern with either a simple variable or reluctant quantifier.");
+        }
+
+        if (matchSpec.isAllRows()) {
+            throw new TableException("All rows per match mode is not supported yet.");
+        }
+
+        final int[] partitionKeys = matchSpec.getPartition().getFieldIndices();
+        final InternalTypeInfo<RowData> inputTypeInfo =
+                (InternalTypeInfo<RowData>) inputTransform.getOutputType();
+        final TypeSerializer<RowData> inputSerializer =
+                inputTypeInfo.createSerializer(planner.getExecEnv().getConfig());
+        final NFACompiler.NFAFactory<RowData> nfaFactory =
+                NFACompiler.compileFactory(cepPattern, false);
+        final MatchCodeGenerator generator =
+                new MatchCodeGenerator(
+                        new CodeGeneratorContext(config),
+                        planner.createRelBuilder(),
+                        false, // nullableInput
+                        JavaScalaConversionUtil.toScala(cepPatternAndNames.f1),
+                        JavaScalaConversionUtil.toScala(Optional.empty()),
+                        CodeGenUtils.DEFAULT_COLLECTOR_TERM());
+        generator.bindInput(
+                inputRowType,
+                CodeGenUtils.DEFAULT_INPUT1_TERM(),
+                JavaScalaConversionUtil.toScala(Optional.empty()));
+        final PatternProcessFunctionRunner patternProcessFunction =
+                generator.generateOneRowPerMatchExpression(
+                        (RowType) getOutputType(), partitionKeys, matchSpec.getMeasures());
+        final CepOperator<RowData, RowData, RowData> operator =
+                new CepOperator<>(
+                        inputSerializer,
+                        isProcTime(inputRowType),
+                        nfaFactory,
+                        eventComparator,
+                        cepPattern.getAfterMatchSkipStrategy(),
+                        patternProcessFunction,
+                        null);
+        final OneInputTransformation<RowData, RowData> transform =
+                ExecNodeUtil.createOneInputTransformation(
+                        timestampedInputTransform,
+                        createTransformationMeta(MATCH_TRANSFORMATION, config),
+                        operator,
+                        InternalTypeInfo.of(getOutputType()),
+                        timestampedInputTransform.getParallelism());
+        final RowDataKeySelector selector =
+                KeySelectorUtil.getRowDataSelector(partitionKeys, inputTypeInfo);
+        transform.setStateKeySelector(selector);
+        transform.setStateKeyType(selector.getProducedType());
+
+        if (inputsContainSingleton()) {
+            transform.setParallelism(1);
+            transform.setMaxParallelism(1);
+        }
+        return transform;
+    }
+
+    public void checkOrderKeys(RowType inputRowType) {}
+
+    private EventComparator<RowData> createEventComparator(
+            ExecNodeConfig config, RowType inputRowType) {
+        SortSpec orderKeys = matchSpec.getOrderKeys();
+        if (orderKeys.getFieldIndices().length > 1) {
+            GeneratedRecordComparator rowComparator =
+                    ComparatorCodeGenerator.gen(
+                            config, "RowDataComparator", inputRowType, orderKeys);
+            return new RowDataEventComparator(rowComparator);
+        } else {
+            return null;
+        }
+    }
+
+    public Transformation<RowData> translateOrder(
+            Transformation<RowData> inputTransform, RowType inputRowType, ReadableConfig config) {
+        return inputTransform;
+    }
+
+    @VisibleForTesting
+    public static Tuple2<Pattern<RowData, RowData>, List<String>> translatePattern(

Review Comment:
   @godfreyhe, `translatePattern` is called by `org.apache.flink.table.planner.match.PatternTranslatorTestBase`, hence this uses `public`.



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