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https://issues.apache.org/jira/browse/TAJO-1658?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14604436#comment-14604436
]
ASF GitHub Bot commented on TAJO-1658:
--------------------------------------
Github user jihoonson commented on a diff in the pull request:
https://github.com/apache/tajo/pull/613#discussion_r33417550
--- Diff:
tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/EmptyScanIterator.java
---
@@ -0,0 +1,40 @@
+/*
+ * 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.tajo.engine.planner.physical;
+
+import org.apache.tajo.storage.Tuple;
+
+import java.io.IOException;
+
+/**
+ * Empty Iterator
+ */
+public class EmptyScanIterator implements ScanIterator {
+
+ @Override
+ public boolean hasNext() throws IOException {
+ return false;
+ }
+
+ @Override
+ public Tuple next() throws IOException {
+ throw new IOException(this.getClass().getSimpleName() + "::next() is
invoked.");
--- End diff --
I'm wondering that throwing an exception is better than returning a null.
> Filter push down to underlying storages
> ---------------------------------------
>
> Key: TAJO-1658
> URL: https://issues.apache.org/jira/browse/TAJO-1658
> Project: Tajo
> Issue Type: Sub-task
> Components: physical operator, storage
> Reporter: Hyunsik Choi
> Assignee: Hyunsik Choi
> Fix For: 0.11.0
>
>
> Some storages can filter unqualified rows. For it, SeqScanner should support
> the filter push down to underlying scanners.
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