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https://issues.apache.org/jira/browse/DRILL-6791?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16686539#comment-16686539
]
ASF GitHub Bot commented on DRILL-6791:
---------------------------------------
arina-ielchiieva commented on a change in pull request #1501: DRILL-6791: Scan
projection framework
URL: https://github.com/apache/drill/pull/1501#discussion_r233455585
##########
File path:
exec/java-exec/src/test/java/org/apache/drill/exec/physical/impl/scan/project/TestNullColumnLoader.java
##########
@@ -0,0 +1,329 @@
+/*
+ * 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.physical.impl.scan.project;
+
+import static org.junit.Assert.assertSame;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.drill.common.types.TypeProtos.DataMode;
+import org.apache.drill.common.types.TypeProtos.MajorType;
+import org.apache.drill.common.types.TypeProtos.MinorType;
+import org.apache.drill.common.types.Types;
+import org.apache.drill.exec.physical.impl.scan.project.NullColumnBuilder;
+import org.apache.drill.exec.physical.impl.scan.project.NullColumnLoader;
+import org.apache.drill.exec.physical.impl.scan.project.ResolvedNullColumn;
+import org.apache.drill.exec.physical.rowSet.ResultVectorCache;
+import org.apache.drill.exec.physical.rowSet.impl.NullResultVectorCacheImpl;
+import org.apache.drill.exec.physical.rowSet.impl.ResultVectorCacheImpl;
+import org.apache.drill.exec.record.BatchSchema;
+import org.apache.drill.exec.record.VectorContainer;
+import org.apache.drill.exec.vector.ValueVector;
+import org.apache.drill.test.SubOperatorTest;
+import org.apache.drill.test.rowSet.RowSet.SingleRowSet;
+import org.apache.drill.test.rowSet.schema.SchemaBuilder;
+import org.apache.drill.test.rowSet.RowSetComparison;
+import org.junit.Test;
+
+/**
+ * Test the mechanism that handles all-null columns during projection.
+ * An all-null column is one projected in the query, but which does
+ * not actually exist in the underlying data source (or input
+ * operator.)
+ * <p>
+ * In anticipation of having type information, this mechanism
+ * can create the classic nullable Int null column, or one of
+ * any other type and mode.
+ */
+
+public class TestNullColumnLoader extends SubOperatorTest {
+
+ private ResolvedNullColumn makeNullCol(String name, MajorType nullType) {
+
+ // For this test, we don't need the projection, so just
+ // set it to null.
+
+ return new ResolvedNullColumn(name, nullType, null, 0);
+ }
+
+ private ResolvedNullColumn makeNullCol(String name) {
+ return makeNullCol(name, null);
+ }
+
+ /**
+ * Test the simplest case: default null type, nothing in the vector
+ * cache. Specify no column type, the special NULL type, or a
+ * predefined type. Output types should be set accordingly.
+ */
+
+ @Test
+ public void testBasics() {
+
+ final List<ResolvedNullColumn> defns = new ArrayList<>();
+ defns.add(makeNullCol("unspecified", null));
+ defns.add(makeNullCol("nullType", Types.optional(MinorType.NULL)));
+ defns.add(makeNullCol("specifiedOpt", Types.optional(MinorType.VARCHAR)));
+ defns.add(makeNullCol("specifiedReq", Types.required(MinorType.VARCHAR)));
+ defns.add(makeNullCol("specifiedArray",
Types.repeated(MinorType.VARCHAR)));
+
+ final ResultVectorCache cache = new
NullResultVectorCacheImpl(fixture.allocator());
+ final NullColumnLoader staticLoader = new NullColumnLoader(cache, defns,
null, false);
+
+ // Create a batch
+
+ final VectorContainer output = staticLoader.load(2);
+
+ // Verify values and types
+
+ final BatchSchema expectedSchema = new SchemaBuilder()
+ .add("unspecified", NullColumnLoader.DEFAULT_NULL_TYPE)
+ .add("nullType", NullColumnLoader.DEFAULT_NULL_TYPE)
+ .addNullable("specifiedOpt", MinorType.VARCHAR)
+ .addNullable("specifiedReq", MinorType.VARCHAR)
+ .addArray("specifiedArray", MinorType.VARCHAR)
+ .build();
+ final SingleRowSet expected = fixture.rowSetBuilder(expectedSchema)
+ .addRow(null, null, null, null, new String[] {})
+ .addRow(null, null, null, null, new String[] {})
+ .build();
+
+ new RowSetComparison(expected)
+ .verifyAndClearAll(fixture.wrap(output));
+ staticLoader.close();
+ }
+
+ /**
+ * Test the ability to use a type other than nullable INT for null
+ * columns. This occurs, for example, in the CSV reader where no
+ * column is ever INT (nullable or otherwise) and we want our null
+ * columns to be (non-nullable) VARCHAR.
+ */
+
+ @Test
+ public void testCustomNullType() {
+
+ final List<ResolvedNullColumn> defns = new ArrayList<>();
+ defns.add(makeNullCol("unspecified", null));
+ defns.add(makeNullCol("nullType", MajorType.newBuilder()
+ .setMinorType(MinorType.NULL)
+ .setMode(DataMode.OPTIONAL)
+ .build()));
+ defns.add(makeNullCol("nullTypeReq", MajorType.newBuilder()
+ .setMinorType(MinorType.NULL)
+ .setMode(DataMode.REQUIRED)
Review comment:
How null can be required?
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> Merge scan projection framework into master
> -------------------------------------------
>
> Key: DRILL-6791
> URL: https://issues.apache.org/jira/browse/DRILL-6791
> Project: Apache Drill
> Issue Type: Improvement
> Affects Versions: 1.15.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Priority: Major
> Fix For: 1.15.0
>
>
> Merge the next set of "result set loader" code into master via a PR. This one
> covers the "schema projection" mechanism which:
> * Handles none (SELECT COUNT\(*)), some (SELECT a, b, x) and all (SELECT *)
> projection.
> * Handles null columns (for projection a column "x" that does not exist in
> the base table.)
> * Handles constant columns as used for file metadata (AKA "implicit" columns).
> * Handle schema persistence: the need to reuse the same vectors across
> different scanners
> * Provides a framework for consuming externally-supplied metadata
> * Since we don't yet have a way to provide "real" metadata, obtains metadata
> hints from previous batches and from the projection list (a.b implies that
> "a" is a map, c[0] implies that "c" is an array, etc.)
> * Handles merging the set of data source columns and null columns to create
> the final output batch.
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