/**
* 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.jdbc.test;
import static org.junit.Assert.*;
import static org.hamcrest.CoreMatchers.*;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import org.apache.drill.jdbc.Driver;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Ignore;
import org.junit.Test;
/**
* Tests from DRILL-2288, in which schema information wasn't propagated when a
* scan yielded an empty (zero-row) result set.
*/
public class Drill2288GetColumnsMetadataWhenNoRowsTest {
private static Connection connection;
@BeforeClass
public static void setUpConnection() throws SQLException {
// (Note: Can't use JdbcTest's connect(...) because JdbcTest closes
// Connection--and other JDBC objects--on test method failure, but this test
// class uses some objects across methods.)
connection = new Driver().connect( "jdbc:drill:zk=local", null );
}
@AfterClass
public static void tearDownConnection() throws SQLException {
connection.close();
}
/**
* Tests that an empty JSON file (having zero records) no longer triggers
* breakage in schema propagation. (Case failed before; columns a, b and c
* didn't show up.)
*/
@Test
public void testEmptyJsonFileDoesntSuppressNetSchema1() throws Exception {
Statement stmt = connection.createStatement();
ResultSet results = stmt.executeQuery( "SELECT a, b, c, * FROM cp.`empty.json`" );
// Result set should still have columns even though there are no rows:
ResultSetMetaData metadata = results.getMetaData();
assertThat( "ResultSetMetaData.getColumnCount() should have been > 0",
metadata.getColumnCount(), not( equalTo( 0 ) ) );
assertThat( "Unexpected non-empty results. Test rot?",
false, equalTo( results.next() ) );
}
@Test
public void testEmptyJsonFileDoesntSuppressNetSchema2() throws Exception {
Statement stmt = connection.createStatement();
ResultSet results = stmt.executeQuery( "SELECT a FROM cp.`empty.json`" );
// Result set should still have columns even though there are no rows:
ResultSetMetaData metadata = results.getMetaData();
assertThat( "ResultSetMetaData.getColumnCount() should have been 1",
metadata.getColumnCount(), equalTo( 1 ) );
assertThat( "Unexpected non-empty results. Test rot?",
false, equalTo( results.next() ) );
}
/**
* Tests that an INFORMATION_SCHEMA.TABLES query that has zero rows because of
* a (simple-enough) filter expression using column TABLE_SCHEMA (which
* supports pushdown) still has all columns. (Case failed before; had zero
* columns.)
*/
@Test
public void testInfoSchemaTablesZeroRowsBy_TABLE_SCHEMA_works() throws Exception {
Statement stmt = connection.createStatement();
ResultSet results =
stmt.executeQuery( "SELECT * FROM INFORMATION_SCHEMA.`TABLES`"
+ " WHERE TABLE_SCHEMA = ''" );
// Result set should still have columns even though there are no rows:
ResultSetMetaData metadata = results.getMetaData();
assertThat( "ResultSetMetaData.getColumnCount() should have been > 0",
metadata.getColumnCount(), not( equalTo( 0 ) ) );
assertThat( "Unexpected non-empty results. Test rot?",
false, equalTo( results.next() ) );
}
/** (Worked before (because TABLE_CATALOG test not pushed down).) */
@Test
public void testInfoSchemaTablesZeroRowsBy_TABLE_CATALOG_works() throws Exception {
Statement stmt = connection.createStatement();
ResultSet results =
stmt.executeQuery( "SELECT * FROM INFORMATION_SCHEMA.`TABLES`"
+ " WHERE TABLE_CATALOG = ''" );
// Result set should still have columns even though there are no rows:
ResultSetMetaData metadata = results.getMetaData();
assertThat( "ResultSetMetaData.getColumnCount() should have been > 0",
metadata.getColumnCount(), not( equalTo( 0 ) ) );
assertThat( "Unexpected non-empty results. Test rot?",
false, equalTo( results.next() ) );
}
/** (Failed before (because TABLE_NAME test is pushed down).) */
@Test
public void testInfoSchemaTablesZeroRowsBy_TABLE_NAME_works()
throws Exception {
Statement stmt = connection.createStatement();
ResultSet results =
stmt.executeQuery(
"SELECT * FROM INFORMATION_SCHEMA.`TABLES` WHERE TABLE_NAME = ''" );
// Result set should still have columns even though there are no rows:
ResultSetMetaData metadata = results.getMetaData();
assertThat( "ResultSetMetaData.getColumnCount() should have been > 0",
metadata.getColumnCount(), not( equalTo( 0 ) ) );
assertThat( "Unexpected non-empty results. Test rot?",
false, equalTo( results.next() ) );
}
/** (Worked before.) */
@Test
public void testInfoSchemaTablesZeroRowsByLimitWorks() throws Exception {
Statement stmt = connection.createStatement();
ResultSet results =
stmt.executeQuery(
"SELECT * FROM INFORMATION_SCHEMA.`TABLES` LIMIT 0" );
// Result set should still have columns even though there are no rows:
ResultSetMetaData metadata = results.getMetaData();
assertThat( "ResultSetMetaData.getColumnCount() should have been > 0",
metadata.getColumnCount(), not( equalTo( 0 ) ) );
assertThat( "Unexpected non-empty results. Test rot?",
false, equalTo( results.next() ) );
}
/** (Worked before.) */
@Test
public void testInfoSchemaTablesZeroRowsByWhereFalseWorks() throws Exception {
Statement stmt = connection.createStatement();
ResultSet results =
stmt.executeQuery(
"SELECT * FROM INFORMATION_SCHEMA.`TABLES` WHERE FALSE" );
// Result set should still have columns even though there are no rows:
ResultSetMetaData metadata = results.getMetaData();
assertThat( "ResultSetMetaData.getColumnCount() should have been > 0",
metadata.getColumnCount(), not( equalTo( 0 ) ) );
assertThat( "Unexpected non-empty results. Test rot?",
false, equalTo( results.next() ) );
}
/** (Failed before (because table schema and name tests are pushed down).) */
@Test
public void testGetTablesZeroRowsByTableSchemaOrNameWorks() throws Exception {
DatabaseMetaData dbMetadata = connection.getMetaData();
ResultSet results = dbMetadata.getTables( "NoSuchCatalog", "NoSuchSchema",
"NoSuchTable", new String[0] );
// Result set should still have columns even though there are no rows:
ResultSetMetaData metadata = results.getMetaData();
assertThat( "ResultSetMetaData.getColumnCount() should have been > 0",
metadata.getColumnCount(), not( equalTo( 0 ) ) );
assertThat( "Unexpected non-empty results. Test rot?",
false, equalTo( results.next() ) );
}
}