Github user amansinha100 commented on a diff in the pull request:
https://github.com/apache/drill/pull/1066#discussion_r157854723
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/planner/DrillRelBuilder.java
---
@@ -0,0 +1,69 @@
+/*
+ * 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.drill.exec.planner;
+
+import org.apache.calcite.plan.Context;
+import org.apache.calcite.plan.Contexts;
+import org.apache.calcite.plan.RelOptCluster;
+import org.apache.calcite.plan.RelOptSchema;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.core.RelFactories;
+import org.apache.calcite.tools.RelBuilder;
+import org.apache.calcite.tools.RelBuilderFactory;
+import org.apache.calcite.util.Util;
+
+public class DrillRelBuilder extends RelBuilder {
+ private final RelFactories.FilterFactory filterFactory;
+
+ protected DrillRelBuilder(Context context, RelOptCluster cluster,
RelOptSchema relOptSchema) {
+ super(context, cluster, relOptSchema);
+ this.filterFactory =
+ Util.first(context.unwrap(RelFactories.FilterFactory.class),
+ RelFactories.DEFAULT_FILTER_FACTORY);
+ }
+
+ /**
+ * Original method {@link RelBuilder#empty} returns empty values rel.
+ * In the order to preserve dara row types, filter with false predicate
is created.
+ */
+ @Override
+ public RelBuilder empty() {
--- End diff --
Is a separate DrillRelBuilder absolutely needed ? Should the original
behavior of empty() in Calcite be changed to preserve the RowType of the input
? The fewer things we extend in Drill the better.
---
