[GitHub] [druid] jon-wei commented on a change in pull request #9294: SQL join support for lookups.

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

jon-wei commented on a change in pull request #9294: SQL join support for lookups.
URL: https://github.com/apache/druid/pull/9294#discussion_r373243510
 
 

 ##########
 File path: sql/src/main/java/org/apache/druid/sql/calcite/rel/DruidJoinQueryRel.java
 ##########
 @@ -0,0 +1,344 @@
+/*
+ * 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.rel;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+import org.apache.calcite.plan.RelOptCluster;
+import org.apache.calcite.plan.RelOptCost;
+import org.apache.calcite.plan.RelOptPlanner;
+import org.apache.calcite.plan.RelOptRule;
+import org.apache.calcite.plan.RelTraitSet;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.RelWriter;
+import org.apache.calcite.rel.core.Join;
+import org.apache.calcite.rel.core.JoinRelType;
+import org.apache.calcite.rel.metadata.RelMetadataQuery;
+import org.apache.calcite.rel.type.RelDataType;
+import org.apache.calcite.rex.RexNode;
+import org.apache.druid.java.util.common.IAE;
+import org.apache.druid.java.util.common.Pair;
+import org.apache.druid.java.util.common.StringUtils;
+import org.apache.druid.java.util.common.guava.Sequence;
+import org.apache.druid.query.DataSource;
+import org.apache.druid.query.JoinDataSource;
+import org.apache.druid.query.QueryDataSource;
+import org.apache.druid.query.TableDataSource;
+import org.apache.druid.segment.join.JoinType;
+import org.apache.druid.sql.calcite.expression.DruidExpression;
+import org.apache.druid.sql.calcite.expression.Expressions;
+import org.apache.druid.sql.calcite.planner.Calcites;
+import org.apache.druid.sql.calcite.table.RowSignature;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * DruidRel that uses a {@link JoinDataSource}.
+ */
+public class DruidJoinQueryRel extends DruidRel<DruidJoinQueryRel>
+{
+  private static final TableDataSource DUMMY_DATA_SOURCE = new TableDataSource("__join__");
+  private static final double COST_FACTOR = 100.0;
+
+  private final PartialDruidQuery partialQuery;
+  private final Join joinRel;
+  private RelNode left;
+  private RelNode right;
+
+  private DruidJoinQueryRel(
+      RelOptCluster cluster,
+      RelTraitSet traitSet,
+      Join joinRel,
+      PartialDruidQuery partialQuery,
+      QueryMaker queryMaker
+  )
+  {
+    super(cluster, traitSet, queryMaker);
+    this.joinRel = joinRel;
+    this.left = joinRel.getLeft();
+    this.right = joinRel.getRight();
+    this.partialQuery = partialQuery;
+  }
+
+  public static DruidJoinQueryRel create(final Join joinRel, final QueryMaker queryMaker)
+  {
+    return new DruidJoinQueryRel(
+        joinRel.getCluster(),
+        joinRel.getTraitSet(),
+        joinRel,
+        PartialDruidQuery.create(joinRel),
+        queryMaker
+    );
+  }
+
+  @Override
+  public PartialDruidQuery getPartialDruidQuery()
+  {
+    return partialQuery;
+  }
+
+  @Override
+  public Sequence<Object[]> runQuery()
+  {
+    // runQuery doesn't need to finalize aggregations, because the fact that runQuery is happening suggests this
+    // is the outermost query and it will actually get run as a native query. Druid's native query layer will
+    // finalize aggregations for the outermost query even if we don't explicitly ask it to.
+
+    final DruidQuery query = toDruidQuery(false);
+    return getQueryMaker().runQuery(query);
+  }
+
+  @Override
+  public DruidJoinQueryRel withPartialQuery(final PartialDruidQuery newQueryBuilder)
+  {
+    return new DruidJoinQueryRel(
+        getCluster(),
+        getTraitSet().plusAll(newQueryBuilder.getRelTraits()),
+        joinRel,
+        newQueryBuilder,
+        getQueryMaker()
+    );
+  }
+
+  @Override
+  public int getQueryCount()
+  {
+    return ((DruidRel<?>) left).getQueryCount() + ((DruidRel<?>) right).getQueryCount();
+  }
+
+  @Override
+  public DruidQuery toDruidQuery(final boolean finalizeAggregations)
+  {
+    final DruidRel<?> leftDruidRel = (DruidRel<?>) left;
+    final DruidQuery leftQuery = Preconditions.checkNotNull((leftDruidRel).toDruidQuery(false), "leftQuery");
+    final RowSignature leftSignature = leftQuery.getOutputRowSignature();
+    final DataSource leftDataSource;
+
+    final DruidRel<?> rightDruidRel = (DruidRel<?>) right;
+    final DruidQuery rightQuery = Preconditions.checkNotNull(rightDruidRel.toDruidQuery(false), "rightQuery");
+    final RowSignature rightSignature = rightQuery.getOutputRowSignature();
+    final DataSource rightDataSource;
+
+    // Left rel: allow direct embedding of scans/mappings including those of joins.
+    if (DruidRels.isScanOrMapping(leftDruidRel, true)) {
+      leftDataSource = leftQuery.getDataSource();
+    } else {
+      leftDataSource = new QueryDataSource(leftQuery.getQuery());
+    }
+
+    // Right rel: allow direct embedding of scans/mappings, excluduing joins (those must be done as subqueries).
 
 Review comment:
   excluduing -> excluding

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