RelOptMaterialization.java
/*
* 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.plan;
import org.apache.calcite.config.CalciteSystemProperty;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.RelShuttleImpl;
import org.apache.calcite.rel.core.Filter;
import org.apache.calcite.rel.core.Project;
import org.apache.calcite.rel.core.TableScan;
import org.apache.calcite.rel.logical.LogicalJoin;
import org.apache.calcite.rel.metadata.DefaultRelMetadataProvider;
import org.apache.calcite.rel.rules.CoreRules;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.rex.RexUtil;
import org.apache.calcite.schema.Table;
import org.apache.calcite.schema.impl.StarTable;
import org.apache.calcite.sql.SqlExplainFormat;
import org.apache.calcite.sql.SqlExplainLevel;
import org.apache.calcite.tools.Program;
import org.apache.calcite.tools.Programs;
import org.apache.calcite.util.Util;
import org.apache.calcite.util.mapping.Mappings;
import com.google.common.collect.ImmutableList;
import org.checkerframework.checker.nullness.qual.Nullable;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import static org.apache.calcite.linq4j.Nullness.castNonNull;
import static java.util.Objects.requireNonNull;
/**
* Records that a particular query is materialized by a particular table.
*/
public class RelOptMaterialization {
public final RelNode tableRel;
public final @Nullable RelOptTable starRelOptTable;
public final @Nullable StarTable starTable;
public final List<String> qualifiedTableName;
public final RelNode queryRel;
/**
* Creates a RelOptMaterialization.
*/
public RelOptMaterialization(RelNode tableRel, RelNode queryRel,
@Nullable RelOptTable starRelOptTable, List<String> qualifiedTableName) {
this.queryRel = requireNonNull(queryRel, "queryRel");
this.tableRel =
RelOptUtil.createCastRel(requireNonNull(tableRel, "tableRel"),
queryRel.getRowType(), false);
this.starRelOptTable = starRelOptTable;
if (starRelOptTable == null) {
this.starTable = null;
} else {
this.starTable = starRelOptTable.unwrapOrThrow(StarTable.class);
}
this.qualifiedTableName = qualifiedTableName;
}
/**
* Converts a relational expression to one that uses a
* {@link org.apache.calcite.schema.impl.StarTable}.
*
* <p>The relational expression is already in leaf-join-form, per
* {@link #toLeafJoinForm(org.apache.calcite.rel.RelNode)}.
*
* @return Rewritten expression, or null if expression cannot be rewritten
* to use the star
*/
public static @Nullable RelNode tryUseStar(RelNode rel,
final RelOptTable starRelOptTable) {
final StarTable starTable = starRelOptTable.unwrapOrThrow(StarTable.class);
RelNode rel2 =
rel.accept(new RelShuttleImpl() {
@Override public RelNode visit(TableScan scan) {
RelOptTable relOptTable = scan.getTable();
final Table table = relOptTable.unwrap(Table.class);
if (Objects.equals(table, starTable.tables.get(0))) {
Mappings.TargetMapping mapping =
Mappings.createShiftMapping(
starRelOptTable.getRowType().getFieldCount(),
0, 0, relOptTable.getRowType().getFieldCount());
final RelOptCluster cluster = scan.getCluster();
final RelNode scan2 =
starRelOptTable.toRel(ViewExpanders.simpleContext(cluster));
return RelOptUtil.createProject(scan2,
Mappings.asListNonNull(mapping.inverse()));
}
return scan;
}
@Override public RelNode visit(LogicalJoin join) {
for (;;) {
RelNode rel = super.visit(join);
if (rel == join || !(rel instanceof LogicalJoin)) {
return rel;
}
join = (LogicalJoin) rel;
final ProjectFilterTable left =
ProjectFilterTable.of(join.getLeft());
if (left != null) {
final ProjectFilterTable right =
ProjectFilterTable.of(join.getRight());
if (right != null) {
try {
match(left, right, join.getCluster());
} catch (Util.FoundOne e) {
return (RelNode) requireNonNull(e.getNode(),
"FoundOne.getNode");
}
}
}
}
}
/** Throws a {@link org.apache.calcite.util.Util.FoundOne} containing
* a {@link org.apache.calcite.rel.logical.LogicalTableScan} on
* success. (Yes, an exception for normal operation.) */
private void match(ProjectFilterTable left, ProjectFilterTable right,
RelOptCluster cluster) {
final Mappings.TargetMapping leftMapping = left.mapping();
final Mappings.TargetMapping rightMapping = right.mapping();
final RelOptTable leftRelOptTable = left.getTable();
final Table leftTable = leftRelOptTable.unwrap(Table.class);
final int leftCount = leftRelOptTable.getRowType().getFieldCount();
final RelOptTable rightRelOptTable = right.getTable();
final Table rightTable = rightRelOptTable.unwrap(Table.class);
if (leftTable instanceof StarTable
&& rightTable != null
&& ((StarTable) leftTable).tables.contains(rightTable)) {
final int offset =
((StarTable) leftTable).columnOffset(rightTable);
Mappings.TargetMapping mapping =
Mappings.merge(leftMapping,
Mappings.offsetTarget(
Mappings.offsetSource(rightMapping, offset),
leftMapping.getTargetCount()));
final RelNode project =
RelOptUtil.createProject(
leftRelOptTable.toRel(ViewExpanders.simpleContext(cluster)),
Mappings.asListNonNull(mapping.inverse()));
final List<RexNode> conditions = new ArrayList<>();
if (left.condition != null) {
conditions.add(left.condition);
}
if (right.condition != null) {
conditions.add(
RexUtil.apply(mapping,
RexUtil.shift(right.condition, offset)));
}
final RelNode filter =
RelOptUtil.createFilter(project, conditions);
throw new Util.FoundOne(filter);
}
if (rightTable instanceof StarTable
&& leftTable != null
&& ((StarTable) rightTable).tables.contains(leftTable)) {
final int offset =
((StarTable) rightTable).columnOffset(leftTable);
Mappings.TargetMapping mapping =
Mappings.merge(
Mappings.offsetSource(leftMapping, offset),
Mappings.offsetTarget(rightMapping, leftCount));
final RelNode project =
RelOptUtil.createProject(
rightRelOptTable.toRel(ViewExpanders.simpleContext(cluster)),
Mappings.asListNonNull(mapping.inverse()));
final List<RexNode> conditions = new ArrayList<>();
if (left.condition != null) {
conditions.add(
RexUtil.apply(mapping,
RexUtil.shift(left.condition, offset)));
}
if (right.condition != null) {
conditions.add(RexUtil.apply(mapping, right.condition));
}
final RelNode filter =
RelOptUtil.createFilter(project, conditions);
throw new Util.FoundOne(filter);
}
}
});
if (rel2 == rel) {
// No rewrite happened.
return null;
}
final Program program =
Programs.hep(
ImmutableList.of(CoreRules.PROJECT_FILTER_TRANSPOSE,
CoreRules.AGGREGATE_PROJECT_MERGE,
CoreRules.AGGREGATE_FILTER_TRANSPOSE),
false,
DefaultRelMetadataProvider.INSTANCE);
return program.run(castNonNull(null), rel2, castNonNull(null),
ImmutableList.of(),
ImmutableList.of());
}
/** A table scan and optional project mapping and filter condition. */
private static class ProjectFilterTable {
final @Nullable RexNode condition;
final Mappings.@Nullable TargetMapping mapping;
final TableScan scan;
private ProjectFilterTable(@Nullable RexNode condition,
Mappings.@Nullable TargetMapping mapping, TableScan scan) {
this.condition = condition;
this.mapping = mapping;
this.scan = requireNonNull(scan, "scan");
}
static @Nullable ProjectFilterTable of(RelNode node) {
if (node instanceof Filter) {
final Filter filter = (Filter) node;
return of2(filter.getCondition(), filter.getInput());
} else {
return of2(null, node);
}
}
private static @Nullable ProjectFilterTable of2(@Nullable RexNode condition, RelNode node) {
if (node instanceof Project) {
final Project project = (Project) node;
return of3(condition, project.getMapping(), project.getInput());
} else {
return of3(condition, null, node);
}
}
private static @Nullable ProjectFilterTable of3(@Nullable RexNode condition,
Mappings.@Nullable TargetMapping mapping, RelNode node) {
if (node instanceof TableScan) {
return new ProjectFilterTable(condition, mapping,
(TableScan) node);
} else {
return null;
}
}
public Mappings.TargetMapping mapping() {
return mapping != null
? mapping
: Mappings.createIdentity(scan.getRowType().getFieldCount());
}
public RelOptTable getTable() {
return scan.getTable();
}
}
/**
* Converts a relational expression to a form where
* {@link org.apache.calcite.rel.logical.LogicalJoin}s are
* as close to leaves as possible.
*/
public static RelNode toLeafJoinForm(RelNode rel) {
final Program program =
Programs.hep(
ImmutableList.of(CoreRules.JOIN_PROJECT_RIGHT_TRANSPOSE,
CoreRules.JOIN_PROJECT_LEFT_TRANSPOSE,
CoreRules.FILTER_INTO_JOIN,
CoreRules.PROJECT_REMOVE,
CoreRules.PROJECT_MERGE),
false,
DefaultRelMetadataProvider.INSTANCE);
if (CalciteSystemProperty.DEBUG.value()) {
System.out.println(
RelOptUtil.dumpPlan("before", rel, SqlExplainFormat.TEXT,
SqlExplainLevel.DIGEST_ATTRIBUTES));
}
final RelNode rel2 =
program.run(castNonNull(null), rel, castNonNull(null),
ImmutableList.of(), ImmutableList.of());
if (CalciteSystemProperty.DEBUG.value()) {
System.out.println(
RelOptUtil.dumpPlan("after", rel2, SqlExplainFormat.TEXT,
SqlExplainLevel.DIGEST_ATTRIBUTES));
}
return rel2;
}
}