| /* |
| * 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.druid.sql.calcite.rule; |
| |
| import org.apache.calcite.plan.RelOptRule; |
| import org.apache.calcite.plan.RelOptRuleCall; |
| import org.apache.calcite.rel.RelNode; |
| import org.apache.calcite.rel.core.Union; |
| import org.apache.calcite.util.mapping.Mappings; |
| import org.apache.druid.java.util.common.ISE; |
| import org.apache.druid.query.TableDataSource; |
| import org.apache.druid.segment.column.RowSignature; |
| import org.apache.druid.sql.calcite.rel.DruidQueryRel; |
| import org.apache.druid.sql.calcite.rel.DruidRel; |
| import org.apache.druid.sql.calcite.rel.DruidRels; |
| import org.apache.druid.sql.calcite.rel.DruidUnionDataSourceRel; |
| import org.apache.druid.sql.calcite.rel.PartialDruidQuery; |
| import org.apache.druid.sql.calcite.table.DruidTable; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.Optional; |
| |
| /** |
| * Creates a {@link DruidUnionDataSourceRel} from various {@link DruidQueryRel} inputs that represent simple |
| * table scans. |
| */ |
| public class DruidUnionDataSourceRule extends RelOptRule |
| { |
| private static final DruidUnionDataSourceRule INSTANCE = new DruidUnionDataSourceRule(); |
| |
| private DruidUnionDataSourceRule() |
| { |
| super( |
| operand( |
| Union.class, |
| operand(DruidRel.class, none()), |
| operand(DruidQueryRel.class, none()) |
| ) |
| ); |
| } |
| |
| public static DruidUnionDataSourceRule instance() |
| { |
| return INSTANCE; |
| } |
| |
| @Override |
| public boolean matches(RelOptRuleCall call) |
| { |
| final Union unionRel = call.rel(0); |
| final DruidRel<?> firstDruidRel = call.rel(1); |
| final DruidQueryRel secondDruidRel = call.rel(2); |
| |
| // Can only do UNION ALL of inputs that have compatible schemas (or schema mappings). |
| return unionRel.all && isUnionCompatible(firstDruidRel, secondDruidRel); |
| } |
| |
| @Override |
| public void onMatch(final RelOptRuleCall call) |
| { |
| final Union unionRel = call.rel(0); |
| final DruidRel<?> firstDruidRel = call.rel(1); |
| final DruidQueryRel secondDruidRel = call.rel(2); |
| |
| if (firstDruidRel instanceof DruidUnionDataSourceRel) { |
| // Unwrap and flatten the inputs to the Union. |
| final RelNode newUnionRel = call.builder() |
| .pushAll(firstDruidRel.getInputs()) |
| .push(secondDruidRel) |
| .union(true, firstDruidRel.getInputs().size() + 1) |
| .build(); |
| |
| call.transformTo( |
| DruidUnionDataSourceRel.create( |
| (Union) newUnionRel, |
| getColumnNamesIfTableOrUnion(firstDruidRel).get(), |
| firstDruidRel.getQueryMaker() |
| ) |
| ); |
| } else { |
| // Sanity check. |
| if (!(firstDruidRel instanceof DruidQueryRel)) { |
| throw new ISE("Expected first rel to be a DruidQueryRel, but it was %s", firstDruidRel.getClass().getName()); |
| } |
| |
| call.transformTo( |
| DruidUnionDataSourceRel.create( |
| unionRel, |
| getColumnNamesIfTableOrUnion(firstDruidRel).get(), |
| firstDruidRel.getQueryMaker() |
| ) |
| ); |
| } |
| } |
| |
| private static boolean isUnionCompatible(final DruidRel<?> first, final DruidRel<?> second) |
| { |
| final Optional<List<String>> columnNames = getColumnNamesIfTableOrUnion(first); |
| return columnNames.isPresent() && columnNames.equals(getColumnNamesIfTableOrUnion(second)); |
| } |
| |
| static Optional<List<String>> getColumnNamesIfTableOrUnion(final DruidRel<?> druidRel) |
| { |
| final PartialDruidQuery partialQuery = druidRel.getPartialDruidQuery(); |
| |
| final Optional<DruidTable> druidTable = |
| DruidRels.druidTableIfLeafRel(druidRel) |
| .filter(table -> table.getDataSource() instanceof TableDataSource); |
| |
| if (druidTable.isPresent() && DruidRels.isScanOrMapping(druidRel, false)) { |
| // This rel is a table scan or mapping. |
| |
| if (partialQuery.stage() == PartialDruidQuery.Stage.SCAN) { |
| return Optional.of(druidTable.get().getRowSignature().getColumnNames()); |
| } else { |
| // Sanity check. Expected to be true due to the "scan or mapping" check. |
| if (partialQuery.stage() != PartialDruidQuery.Stage.SELECT_PROJECT) { |
| throw new ISE("Expected stage %s but got %s", PartialDruidQuery.Stage.SELECT_PROJECT, partialQuery.stage()); |
| } |
| |
| // Apply the mapping (with additional sanity checks). |
| final RowSignature tableSignature = druidTable.get().getRowSignature(); |
| final Mappings.TargetMapping mapping = partialQuery.getSelectProject().getMapping(); |
| |
| if (mapping.getSourceCount() != tableSignature.size()) { |
| throw new ISE( |
| "Expected mapping with %d columns but got %d columns", |
| tableSignature.size(), |
| mapping.getSourceCount() |
| ); |
| } |
| |
| final List<String> retVal = new ArrayList<>(); |
| |
| for (int i = 0; i < mapping.getTargetCount(); i++) { |
| final int sourceField = mapping.getSourceOpt(i); |
| retVal.add(tableSignature.getColumnName(sourceField)); |
| } |
| |
| return Optional.of(retVal); |
| } |
| } else if (!druidTable.isPresent() && druidRel instanceof DruidUnionDataSourceRel) { |
| // This rel is a union itself. |
| |
| return Optional.of(((DruidUnionDataSourceRel) druidRel).getUnionColumnNames()); |
| } else { |
| return Optional.empty(); |
| } |
| } |
| } |