| /** |
| * 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.hadoop.sqoop.manager; |
| |
| import java.io.IOException; |
| import java.sql.PreparedStatement; |
| import java.sql.ResultSet; |
| import java.sql.SQLException; |
| import java.util.ArrayList; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.sqoop.SqoopOptions; |
| import org.apache.hadoop.sqoop.util.ImportException; |
| |
| /** |
| * Manages connections to Postgresql databases |
| */ |
| public class PostgresqlManager extends GenericJdbcManager { |
| |
| public static final Log LOG = LogFactory.getLog(PostgresqlManager.class.getName()); |
| |
| // driver class to ensure is loaded when making db connection. |
| private static final String DRIVER_CLASS = "org.postgresql.Driver"; |
| |
| private static final int POSTGRESQL_FETCH_SIZE = 50; // Fetch 50 rows at a time. |
| |
| // set to true after we warn the user that we can use direct fastpath. |
| private static boolean warningPrinted = false; |
| |
| public PostgresqlManager(final SqoopOptions opts) { |
| super(DRIVER_CLASS, opts); |
| } |
| |
| protected PostgresqlManager(final SqoopOptions opts, boolean ignored) { |
| // constructor used by subclasses to avoid the --direct warning. |
| super(DRIVER_CLASS, opts); |
| } |
| |
| @Override |
| public void close() throws SQLException { |
| if (this.hasOpenConnection()) { |
| this.getConnection().commit(); // Commit any changes made thus far. |
| } |
| |
| super.close(); |
| } |
| |
| @Override |
| protected String getColNamesQuery(String tableName) { |
| // Use LIMIT to return fast |
| return "SELECT t.* FROM " + escapeTableName(tableName) + " AS t LIMIT 1"; |
| } |
| |
| @Override |
| public void importTable(ImportJobContext context) |
| throws IOException, ImportException { |
| |
| // The user probably should have requested --direct to invoke pg_dump. |
| // Display a warning informing them of this fact. |
| if (!PostgresqlManager.warningPrinted) { |
| String connectString = context.getOptions().getConnectString(); |
| |
| LOG.warn("It looks like you are importing from postgresql."); |
| LOG.warn("This transfer can be faster! Use the --direct"); |
| LOG.warn("option to exercise a postgresql-specific fast path."); |
| |
| PostgresqlManager.warningPrinted = true; // don't display this twice. |
| } |
| |
| // Then run the normal importTable() method. |
| super.importTable(context); |
| } |
| |
| @Override |
| public String getPrimaryKey(String tableName) { |
| // Postgresql stores table names using lower-case internally; need |
| // to always convert to lowercase before querying the metadata dictionary. |
| return super.getPrimaryKey(tableName.toLowerCase()); |
| } |
| |
| /** |
| * Executes an arbitrary SQL statement. Sets the cursor fetch size |
| * to ensure the entire table is not buffered in RAM before reading |
| * any rows. A consequence of this is that every ResultSet returned |
| * by this method *MUST* be close()'d, or read to exhaustion before |
| * another query can be executed from this ConnManager instance. |
| * |
| * @param stmt The SQL statement to execute |
| * @return A ResultSet encapsulating the results or null on error |
| */ |
| protected ResultSet execute(String stmt, Object... args) throws SQLException { |
| PreparedStatement statement = null; |
| statement = this.getConnection().prepareStatement(stmt, |
| ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY); |
| statement.setFetchSize(POSTGRESQL_FETCH_SIZE); |
| if (null != args) { |
| for (int i = 0; i < args.length; i++) { |
| statement.setObject(i + 1, args[i]); |
| } |
| } |
| |
| LOG.info("Executing SQL statement: " + stmt); |
| return statement.executeQuery(); |
| } |
| } |
| |