HanumathRao commented on code in PR #3597: URL: https://github.com/apache/calcite/pull/3597#discussion_r1451798326
########## core/src/main/java/org/apache/calcite/rel/rules/SingleValuesOptimizationRules.java: ########## @@ -0,0 +1,374 @@ +/* + * 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.rules; + +import org.apache.calcite.plan.RelOptRule; +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.JoinRelType; +import org.apache.calcite.rel.core.Project; +import org.apache.calcite.rel.core.Values; +import org.apache.calcite.rel.logical.LogicalValues; +import org.apache.calcite.rex.RexBuilder; +import org.apache.calcite.rex.RexInputRef; +import org.apache.calcite.rex.RexNode; +import org.apache.calcite.rex.RexShuttle; +import org.apache.calcite.rex.RexUtil; +import org.apache.calcite.sql.fun.SqlStdOperatorTable; +import org.apache.calcite.tools.RelBuilder; +import org.apache.calcite.util.ImmutableBitSet; + +import org.checkerframework.checker.nullness.qual.Nullable; +import org.immutables.value.Value; + +import java.util.ArrayList; +import java.util.List; +import java.util.function.BiFunction; +import java.util.function.Predicate; +import java.util.stream.Collectors; + +/** + * Collection of rules which simplify joins which have one of their input as constant relations + * {@link Values} that produce a single row. + * + * <p>Conventionally, the way to represent a single row constant relational expression is + * with a {@link Values} that has one tuple. + * + * @see LogicalValues#createOneRow + */ +public abstract class SingleValuesOptimizationRules { + + public static final RelOptRule JOIN_LEFT_INSTANCE = + SingleValuesOptimizationRules.JoinLeftSingleRuleConfig.DEFAULT.toRule(); + + public static final RelOptRule JOIN_RIGHT_INSTANCE = + SingleValuesOptimizationRules.JoinRightSingleRuleConfig.DEFAULT.toRule(); + + public static final RelOptRule JOIN_LEFT_PROJECT_INSTANCE = + SingleValuesOptimizationRules.JoinLeftSingleValueRuleWithExprConfig.DEFAULT.toRule(); + + public static final RelOptRule JOIN_RIGHT_PROJECT_INSTANCE = + SingleValuesOptimizationRules.JoinRightSingleValueRuleWithExprConfig.DEFAULT.toRule(); + + /** + * Transformer class to transform a Join rel node tree with single constant row {@link Values} + * on either side of the Join to a simplified tree without a Join rel node. + */ + private static class SingleValuesRelTransformer { + + private final Join join; + private final RelNode relNode; + private final Predicate<Join> cannotTransform; + private final BiFunction<RexNode, List<RexNode>, List<RexNode>> litTransformer; + private final boolean valuesAsLeftChild; + private final List<RexNode> literals; + + /** + * A transformer object which transforms a Join rel node tree with constant relation + * node as one of its input to a rel node tree without a Join. + * + * @param join Join which is eligible for removal. + * @param rexNodes List of the expressions that are part of Project + * @param otherNode RelNode which is other side of the Join (apart from Values node) + * @param nonTransformable Predicate to check if the given Join is transformable or not. + * @param isValuesLeftChild TRUE if Values is left child of join, FALSE otherwise. + * @param litTransformer A transformer function supplied by the caller. + * This function is specific to Join Type. + * LEFT/ RIGHT => has logic to produce null values for unmatched rows. + * INNER => produce the rexLiterals specified in the Values node. + */ + protected SingleValuesRelTransformer( + Join join, List<RexNode> rexNodes, RelNode otherNode, + Predicate<Join> nonTransformable, boolean isValuesLeftChild, + BiFunction<RexNode, List<RexNode>, List<RexNode>> litTransformer) { + this.relNode = otherNode; + this.join = join; + this.cannotTransform = nonTransformable; + this.litTransformer = litTransformer; + this.valuesAsLeftChild = isValuesLeftChild; + this.literals = rexNodes; + } + + /** + * A transform function which removes the joins when eligibility criteria is met. + * + * @param relBuilder Relation Builder supplied by the planner framework. + * @return Simplified relNode tree by removing Join. + */ + public @Nullable RelNode transform(RelBuilder relBuilder) { + if (cannotTransform.test(join)) { + return null; + } + int end = valuesAsLeftChild + ? join.getLeft().getRowType().getFieldCount() + : join.getRowType().getFieldCount(); + + int start = valuesAsLeftChild + ? 0 + : join.getLeft().getRowType().getFieldCount(); + ImmutableBitSet bitSet = ImmutableBitSet.range(start, end); + RexNode trueNode = relBuilder.getRexBuilder().makeLiteral(true); + final RexNode filterCondition = + new ReplaceExprWithConstValue(bitSet, + literals, + (valuesAsLeftChild ? 0 : -1) * join.getLeft().getRowType().getFieldCount()) + .go(join.getCondition()); + + RexNode fixedCondition = + valuesAsLeftChild + ? RexUtil.shift(filterCondition, + -1 * join.getLeft().getRowType().getFieldCount()) + : filterCondition; + + List<RexNode> rexLiterals = litTransformer.apply(fixedCondition, literals); + relBuilder.push(relNode) + .filter(join.getJoinType().isOuterJoin() ? trueNode : fixedCondition); + + List<RexNode> rexNodes = relNode + .getRowType() + .getFieldList() + .stream() + .map(fld -> relBuilder.field(fld.getIndex())) + .collect(Collectors.toList()); + + List<RexNode> projects = new ArrayList<>(); + projects.addAll(valuesAsLeftChild ? rexLiterals : rexNodes); + projects.addAll(valuesAsLeftChild ? rexNodes : rexLiterals); + return relBuilder.project(projects).build(); + } + } + + /** + * A rex shuttle to replace field refs with constants from a {@link Values} row. + */ + private static class ReplaceExprWithConstValue extends RexShuttle { + + private final ImmutableBitSet bitSet; + private final List<RexNode> fieldValues; + private final int offset; + + /** + * A RexShuttle replacer which replaces an inputRefs with corresponding + * constant values. + * + * @param bitSet A bitmap to track indices of the inputRef that gets replaced. + * @param values Constant values that are used to replace inputRefs. + * @param offset offset to be applied for the inputRef index to get the constant values. + */ + ReplaceExprWithConstValue(ImmutableBitSet bitSet, List<RexNode> values, int offset) { + this.bitSet = bitSet; + this.fieldValues = values; + this.offset = offset; + } + @Override public RexNode visitInputRef(RexInputRef inputRef) { + if (bitSet.get(inputRef.getIndex())) { + return this.fieldValues.get(inputRef.getIndex() + offset); + } + return super.visitInputRef(inputRef); + } + + public RexNode go(RexNode condition) { + return condition.accept(this); + } + } + + /** + * Abstract prune single value rule that implements SubstitutionRule interface. + */ + protected abstract static class PruneSingleValueRule + extends RelRule<PruneSingleValueRule.Config> + implements SubstitutionRule { + protected PruneSingleValueRule(PruneSingleValueRule.Config config) { + super(config); + } + + protected BiFunction<RexNode, List<RexNode>, List<RexNode>> + getRexTransformer(RexBuilder rexBuilder, + JoinRelType joinRelType) { + switch (joinRelType) { + case LEFT: + case RIGHT: + return (condition, rexLiterals) -> rexLiterals.stream().map(lit -> + rexBuilder.makeCall(SqlStdOperatorTable.CASE, condition, + lit, rexBuilder.makeNullLiteral(lit.getType()))).collect(Collectors.toList()); + default: + return (condition, rexLiterals) -> new ArrayList<>(rexLiterals); + } + } + + /** + * onMatch function contains common optimization logic for all the + * SingleValueOptimization rules. It simplifies the rel node tree by + * removing a Join node and creating a required filter as applicable. + * In case of the LEFT/RIGHT joins, a case expression which produce NULL + * values for non-matching rows will be created as part of a Project node. + * + * @param call A RelOptRuleCall object + * @param values A constant relation node which produces a single row. + * @param project A project node which has dynamic constants (can be null). + * @param join A join node which will get removed. + * @param other A node on the other side of the join (apart from Values) + * @param isLeft Whether a Values node is on the Left side or the right side of the Join. + */ + protected void onMatch(RelOptRuleCall call, Values values, + @Nullable Project project, Join join, + RelNode other, boolean isLeft) { + Predicate<Join> predicate = eligibilityPredicate(isLeft); + List<RexNode> rexNodes; + if (project != null) { + ImmutableBitSet bitSet = ImmutableBitSet.range(0, values.getRowType().getFieldCount()); + RexShuttle shuttle = + new ReplaceExprWithConstValue(bitSet, + new ArrayList<>(values.getTuples().get(0)), + 0); + + rexNodes = project.getProjects().stream() + .map(shuttle::apply) + .collect(Collectors.toList()); + } else { + rexNodes = new ArrayList<>(values.tuples.get(0)); Review Comment: I changed the code to use tuples in both the cases. I haven't created a helper function here because it might be an overkill. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
