asolimando commented on code in PR #3264: URL: https://github.com/apache/calcite/pull/3264#discussion_r1229944269
########## core/src/main/java/org/apache/calcite/rel/metadata/RelMdForeignKeys.java: ########## @@ -0,0 +1,246 @@ +/* + * 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.calcite.rel.metadata; + +import org.apache.calcite.plan.RelOptTable; +import org.apache.calcite.rel.RelNode; +import org.apache.calcite.rel.RelReferentialConstraint; +import org.apache.calcite.rel.SingleRel; +import org.apache.calcite.rel.core.Aggregate; +import org.apache.calcite.rel.core.Calc; +import org.apache.calcite.rel.core.Correlate; +import org.apache.calcite.rel.core.Filter; +import org.apache.calcite.rel.core.Join; +import org.apache.calcite.rel.core.Project; +import org.apache.calcite.rel.core.SetOp; +import org.apache.calcite.rel.core.Sort; +import org.apache.calcite.rel.core.TableModify; +import org.apache.calcite.rel.core.TableScan; +import org.apache.calcite.rel.type.RelDataTypeField; +import org.apache.calcite.rex.RexInputRef; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.rex.RexProgram; +import org.apache.calcite.util.ImmutableBitSet; +import org.apache.calcite.util.Util; +import org.apache.calcite.util.mapping.IntPair; + +import com.google.common.collect.ImmutableListMultimap; +import com.google.common.collect.Maps; + +import java.util.Collection; +import java.util.List; +import java.util.Map; +import java.util.stream.Collectors; + +/** + * RelMdReferentialConstraits supplies a default implementation of + * {@link RelMetadataQuery#getForeignKeys} for the standard logical algebra. + * The relNodes supported are the same to {@link RelMetadataQuery#getUniqueKeys(RelNode)} + */ +public class RelMdForeignKeys + implements MetadataHandler<BuiltInMetadata.ForeignKeys> { + public static final ImmutableBitSet EMPTY_BIT_SET = ImmutableBitSet.of(); + public static final RelMetadataProvider SOURCE = + ReflectiveRelMetadataProvider.reflectiveSource( + new RelMdForeignKeys(), BuiltInMetadata.ForeignKeys.Handler.class); + +//~ Constructors ----------------------------------------------------------- + + private RelMdForeignKeys() {} + +//~ Methods ---------------------------------------------------------------- + + @Override public MetadataDef<BuiltInMetadata.ForeignKeys> getDef() { + return BuiltInMetadata.ForeignKeys.DEF; + } + + public ImmutableBitSet getForeignKeys(Filter rel, RelMetadataQuery mq, boolean ignoreNulls) { + return mq.getForeignKeys(rel.getInput(), ignoreNulls); + } + + public ImmutableBitSet getForeignKeys(Sort rel, RelMetadataQuery mq, boolean ignoreNulls) { + return mq.getForeignKeys(rel.getInput(), ignoreNulls); + } + + public ImmutableBitSet getForeignKeys(Correlate rel, RelMetadataQuery mq, + boolean ignoreNulls) { + return mq.getForeignKeys(rel.getLeft(), ignoreNulls); + } + + public ImmutableBitSet getForeignKeys(TableModify rel, RelMetadataQuery mq, + boolean ignoreNulls) { + return mq.getForeignKeys(rel.getInput(), ignoreNulls); + } + + public ImmutableBitSet getForeignKeys(Join rel, RelMetadataQuery mq, boolean ignoreNulls) { + final RelNode left = rel.getLeft(); + final RelNode right = rel.getRight(); + if (!rel.getJoinType().projectsRight()) { + // only return the foreign keys from the LHS since a semijoin only + // returns the LHS + return mq.getForeignKeys(left, ignoreNulls); + } + + int nLeftColumns = rel.getLeft().getRowType().getFieldList().size(); + ImmutableBitSet outForeignKeys = ImmutableBitSet.of(); + + if (!rel.getJoinType().generatesNullsOnLeft() || ignoreNulls) { + ImmutableBitSet leftInputForeignKeys = mq.getForeignKeys(left, ignoreNulls); + outForeignKeys = outForeignKeys.union(leftInputForeignKeys); + } + if (!rel.getJoinType().generatesNullsOnRight() || ignoreNulls) { + ImmutableBitSet rightInputForeignKeys = mq.getForeignKeys(right, ignoreNulls); + ImmutableBitSet.Builder rightOutForeignKeys = ImmutableBitSet.builder(); + for (int index : rightInputForeignKeys.asList()) { + rightOutForeignKeys.set(index + nLeftColumns); + } + outForeignKeys = outForeignKeys.union(rightOutForeignKeys.build()); + } + return outForeignKeys; + } + + public ImmutableBitSet getForeignKeys(Aggregate rel, RelMetadataQuery mq, + boolean ignoreNulls) { + final ImmutableBitSet groupSet = rel.getGroupSet(); + if (groupSet.isEmpty()) { + return EMPTY_BIT_SET; + } + final ImmutableBitSet inputForeignKeys = mq.getForeignKeys(rel.getInput(), ignoreNulls); + if (inputForeignKeys.isEmpty()) { + return EMPTY_BIT_SET; + } + return groupSet.intersect(inputForeignKeys); + } + + public ImmutableBitSet getForeignKeys(Project rel, RelMetadataQuery mq, + boolean ignoreNulls) { + return getProjectForeignKeys(rel, mq, ignoreNulls, rel.getProjects()); + } + + public ImmutableBitSet getForeignKeys(Calc rel, RelMetadataQuery mq, + boolean ignoreNulls) { + RexProgram program = rel.getProgram(); + return getProjectForeignKeys(rel, mq, ignoreNulls, + Util.transform(program.getProjectList(), program::expandLocalRef)); + } + + private static ImmutableBitSet getProjectForeignKeys(SingleRel rel, RelMetadataQuery mq, + boolean ignoreNulls, + List<RexNode> projExprs) { + + // Single input can be mapped to multiple outputs + final ImmutableListMultimap.Builder<Integer, Integer> inToOutIndexBuilder = + ImmutableListMultimap.builder(); + final ImmutableBitSet.Builder inColumnsBuilder = ImmutableBitSet.builder(); + for (int i = 0; i < projExprs.size(); i++) { + RexNode projExpr = projExprs.get(i); + if (projExpr instanceof RexInputRef) { + int inputIndex = ((RexInputRef) projExpr).getIndex(); + inToOutIndexBuilder.put(inputIndex, i); + inColumnsBuilder.set(inputIndex); + } + } + final ImmutableBitSet inColumnsUsed = inColumnsBuilder.build(); + if (inColumnsUsed.isEmpty()) { + return EMPTY_BIT_SET; + } + + final Map<Integer, ImmutableBitSet> mapInToOutPos = + Maps.transformValues(inToOutIndexBuilder.build().asMap(), ImmutableBitSet::of); + final ImmutableBitSet inputForeignKeys = + mq.getForeignKeys(rel.getInput(), ignoreNulls); + if (inputForeignKeys.isEmpty()) { + return EMPTY_BIT_SET; + } + + ImmutableBitSet allOutColumns = ImmutableBitSet.of(); + for (int index : inputForeignKeys.asList()) { + ImmutableBitSet outColumns = mapInToOutPos.get(index); + if (outColumns != null && !outColumns.isEmpty()) { + allOutColumns = allOutColumns.union(outColumns); + } + } + return allOutColumns.isEmpty() ? EMPTY_BIT_SET : allOutColumns; + } + + public ImmutableBitSet getForeignKeys(TableScan rel, RelMetadataQuery mq, + boolean ignoreNulls) { + final RelOptTable table = rel.getTable(); + final BuiltInMetadata.ForeignKeys.Handler handler = + table.unwrap(BuiltInMetadata.ForeignKeys.Handler.class); + if (handler != null) { + return handler.getForeignKeys(rel, mq, ignoreNulls); + } + + final List<RelReferentialConstraint> referentialConstraints = + table.getReferentialConstraints(); + if (referentialConstraints == null || referentialConstraints.size() == 0) { + return EMPTY_BIT_SET; + } + final List<IntPair> foreignUniquePair = referentialConstraints.stream() + .map(RelReferentialConstraint::getColumnPairs) + .flatMap(Collection::stream) + .collect(Collectors.toList()); + + List<Integer> foreignKeys = IntPair.left(foreignUniquePair); + if (!ignoreNulls) { Review Comment: Looks the opposite to me, if `ignoreNulls` is true, then you want to filter them out (executing the body of the if), no? -- This is an automated message from the Apache Git Service. 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