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https://issues.apache.org/jira/browse/DRILL-3623?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15007685#comment-15007685
]
ASF GitHub Bot commented on DRILL-3623:
---------------------------------------
Github user sudheeshkatkam commented on a diff in the pull request:
https://github.com/apache/drill/pull/193#discussion_r45006594
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/planner/logical/DrillDirectScanRel.java
---
@@ -0,0 +1,111 @@
+/**
+ * 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.logical;
+
+import com.google.common.collect.Iterators;
+import org.apache.calcite.plan.RelOptCluster;
+import org.apache.calcite.plan.RelTraitSet;
+import org.apache.calcite.rel.AbstractRelNode;
+import org.apache.calcite.rel.RelWriter;
+import org.apache.calcite.rel.type.RelDataType;
+import org.apache.drill.common.logical.data.LogicalOperator;
+import org.apache.drill.exec.physical.base.PhysicalOperator;
+import org.apache.drill.exec.planner.physical.DrillScanPrel;
+import org.apache.drill.exec.planner.physical.PhysicalPlanCreator;
+import org.apache.drill.exec.planner.physical.PlannerSettings;
+import org.apache.drill.exec.planner.physical.Prel;
+import org.apache.drill.exec.planner.physical.PrelUtil;
+import org.apache.drill.exec.planner.physical.visitor.PrelVisitor;
+import org.apache.drill.exec.record.BatchSchema;
+import org.apache.drill.exec.store.direct.DirectGroupScan;
+
+import java.io.IOException;
+import java.util.Iterator;
+
+/**
+ * Logical and physical RelNode representing a {@link DirectGroupScan}.
This is not backed by a {@link DrillTable},
+ * unlike {@link DrillScanRel}.
+ */
+public class DrillDirectScanRel extends AbstractRelNode implements
DrillScanPrel, DrillRel {
--- End diff --
With DrillDirectScanRel, the execution plan is: *Screen <-- Project <--
DrillDirectScanRel*. In my experiments ([TPCDS
queries](https://github.com/mapr/drill-test-framework/tree/master/framework/resources/Functional/tpcds/original/hive)),
the total time did not cross 0.6 s.
With VALUES operator, there needs to be a LIMIT(0) operator on top. Then,
the execution plan is: *Screen <-- Project <-- SVR <-- Limit <-- Values*. In my
experiments, sometimes (seen twice) Project and SVR take ~0.5s to setup, and
the query take 2s to complete, but this is **not reproducible.**
> Hive query hangs with limit 0 clause
> ------------------------------------
>
> Key: DRILL-3623
> URL: https://issues.apache.org/jira/browse/DRILL-3623
> Project: Apache Drill
> Issue Type: Bug
> Components: Storage - Hive
> Affects Versions: 1.1.0
> Environment: MapR cluster
> Reporter: Andries Engelbrecht
> Assignee: Sudheesh Katkam
> Fix For: Future
>
>
> Running a select * from hive.table limit 0 does not return (hangs).
> Select * from hive.table limit 1 works fine
> Hive table is about 6GB with 330 files with parquet using snappy compression.
> Data types are int, bigint, string and double.
> Querying directory with parquet files through the DFS plugin works fine
> select * from dfs.root.`/user/hive/warehouse/database/table` limit 0;
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