| /** |
| * 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.sqoop.mapreduce.db; |
| |
| import java.sql.Connection; |
| import java.sql.PreparedStatement; |
| import java.sql.ResultSet; |
| import java.sql.SQLException; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| /** |
| * Connection failure handler for SQL Server which extends basic retry |
| * mechanism for handling connection failures. Retry settings are embedded |
| * in job configuration |
| */ |
| public class SQLServerConnectionFailureHandler |
| extends BasicRetrySQLFailureHandler { |
| |
| private static final Log LOG = |
| LogFactory.getLog(SQLServerConnectionFailureHandler.class); |
| |
| protected static final String CONNECTION_RESET_ERR_REGEX = |
| "(^Connection reset)(.*?)"; |
| protected static final String SQLSTATE_CODE_CONNECTION_RESET = "08S01"; |
| |
| protected static final String VALIDATION_QUERY = |
| "SELECT CONVERT(NVARCHAR, CONTEXT_INFO()) AS contextInfo"; |
| |
| public SQLServerConnectionFailureHandler() { |
| } |
| |
| /** |
| * Handle only connection reset or TCP exceptions. |
| */ |
| public boolean canHandleFailure(Throwable failureCause) { |
| if (!super.canHandleFailure(failureCause)) { |
| return false; |
| } |
| SQLException sqlEx = (SQLException) failureCause; |
| String errStateCode = sqlEx.getSQLState(); |
| boolean canHandle = false; |
| // By default check SQLState code if available |
| if (errStateCode != null) { |
| canHandle = errStateCode == SQLSTATE_CODE_CONNECTION_RESET; |
| } else { |
| errStateCode = "NULL"; |
| // In case SQLState code is not available, check the exception message |
| String errMsg = sqlEx.getMessage(); |
| canHandle = errMsg.matches(CONNECTION_RESET_ERR_REGEX); |
| } |
| |
| if (!canHandle) { |
| LOG.warn("Cannot handle error with SQL State: " + errStateCode); |
| } |
| return canHandle; |
| } |
| |
| /** |
| * Verify the provided connection is valid. For SQL Server we test the |
| * connection by querying the session context. |
| */ |
| protected boolean validateConnection(Connection connection) |
| throws SQLException { |
| boolean isValid = false; |
| String contextInfo = null; |
| if (super.validateConnection(connection)) { |
| // Execute the validation query |
| PreparedStatement stmt = connection.prepareStatement(VALIDATION_QUERY); |
| ResultSet results = stmt.executeQuery(); |
| |
| // Read the context from the result set |
| if (results.next()) { |
| contextInfo = results.getString("contextInfo"); |
| LOG.info("Session context is: " |
| + ((contextInfo == null) ? "NULL" : contextInfo)); |
| isValid = true; |
| } |
| } |
| return isValid; |
| } |
| } |