/EQEmuJSM/mysql-connector-java-5.1.13/src/com/mysql/jdbc/StatementImpl.java

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/*
  Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.

  The MySQL Connector/J is licensed under the terms of the GPL,
  like most MySQL Connectors. There are special exceptions to the
  terms and conditions of the GPL as it is applied to this software,
  see the FLOSS License Exception available on mysql.com.

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; version 2 of the
  License.

  This program is distributed in the hope that it will be useful,  
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  02110-1301 USA
 */
package com.mysql.jdbc;

import java.io.InputStream;
import java.math.BigInteger;
import java.sql.BatchUpdateException;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.Types;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.TimerTask;

import com.mysql.jdbc.exceptions.MySQLStatementCancelledException;
import com.mysql.jdbc.exceptions.MySQLTimeoutException;
import com.mysql.jdbc.profiler.ProfilerEvent;
import com.mysql.jdbc.profiler.ProfilerEventHandler;

/**
 * A Statement object is used for executing a static SQL statement and obtaining
 * the results produced by it.
 *
 * <p>
 * Only one ResultSet per Statement can be open at any point in time. Therefore,
 * if the reading of one ResultSet is interleaved with the reading of another,
 * each must have been generated by different Statements. All statement execute
 * methods implicitly close a statement's current ResultSet if an open one
 * exists.
 * </p>
 *
 * @author Mark Matthews
 * @version $Id: Statement.java 4624 2005-11-28 14:24:29 -0600 (Mon, 28 Nov
 *          2005) mmatthews $
 *
 * @see java.sql.Statement
 * @see ResultSetInternalMethods
 */
public class StatementImpl implements Statement {
        protected static final String PING_MARKER = "/* ping */";
	/**
	 * Thread used to implement query timeouts...Eventually we could be more
	 * efficient and have one thread with timers, but this is a straightforward
	 * and simple way to implement a feature that isn't used all that often.
	 */
	class CancelTask extends TimerTask {

		long connectionId = 0;
		SQLException caughtWhileCancelling = null;
		StatementImpl toCancel;
		
		CancelTask(StatementImpl cancellee) throws SQLException {
			connectionId = connection.getIO().getThreadId();
			toCancel = cancellee;
		}

		public void run() {

			Thread cancelThread = new Thread() {

				public void run() {
					if (connection.getQueryTimeoutKillsConnection()) {
						try {
							toCancel.wasCancelled = true;
							toCancel.wasCancelledByTimeout = true;
							connection.realClose(false, false, true, 
									new MySQLStatementCancelledException(Messages.getString("Statement.ConnectionKilledDueToTimeout")));
						} catch (NullPointerException npe) {
							// not worth guarding against
						} catch (SQLException sqlEx) {
							caughtWhileCancelling = sqlEx;
						}
					} else {
						Connection cancelConn = null;
						java.sql.Statement cancelStmt = null;
	
						try {
							synchronized (cancelTimeoutMutex) {
								cancelConn = connection.duplicate();
								cancelStmt = cancelConn.createStatement();
								cancelStmt.execute("KILL QUERY " + connectionId);
								toCancel.wasCancelled = true;
								toCancel.wasCancelledByTimeout = true;
							}
						} catch (SQLException sqlEx) {
							caughtWhileCancelling = sqlEx;
						} catch (NullPointerException npe) {
							// Case when connection closed while starting to cancel
							// We can't easily synchronize this, because then one thread
							// can't cancel() a running query
	
							// ignore, we shouldn't re-throw this, because the connection's
							// already closed, so the statement has been timed out.
						} finally {
							if (cancelStmt != null) {
								try {
									cancelStmt.close();
								} catch (SQLException sqlEx) {
									throw new RuntimeException(sqlEx.toString());
								}
							}
	
							if (cancelConn != null) {
								try {
									cancelConn.close();
								} catch (SQLException sqlEx) {
									throw new RuntimeException(sqlEx.toString());
								}
							}
							
							toCancel = null;
						}
					}
				}
			};

			cancelThread.start();
		}
	}

	/** Mutex to prevent race between returning query results and noticing
    that we're timed-out or cancelled. */

	protected Object cancelTimeoutMutex = new Object();

	/** Used to generate IDs when profiling. */
	protected static int statementCounter = 1;

	public final static byte USES_VARIABLES_FALSE = 0;

	public final static byte USES_VARIABLES_TRUE = 1;

	public final static byte USES_VARIABLES_UNKNOWN = -1;

	protected boolean wasCancelled = false;
	protected boolean wasCancelledByTimeout = false;

	/** Holds batched commands */
	protected List batchedArgs;

	/** The character converter to use (if available) */
	protected SingleByteCharsetConverter charConverter = null;

	/** The character encoding to use (if available) */
	protected String charEncoding = null;

	/** The connection that created us */
	protected MySQLConnection connection = null;

	protected long connectionId = 0;

	/** The catalog in use */
	protected String currentCatalog = null;

	/** Should we process escape codes? */
	protected boolean doEscapeProcessing = true;

	/** If we're profiling, where should events go to? */
	protected ProfilerEventHandler eventSink = null;

	/** The number of rows to fetch at a time (currently ignored) */
	private int fetchSize = 0;

	/** Has this statement been closed? */
	protected boolean isClosed = false;

	/** The auto_increment value for the last insert */
	protected long lastInsertId = -1;

	/** The max field size for this statement */
	protected int maxFieldSize = MysqlIO.getMaxBuf();

	/**
	 * The maximum number of rows to return for this statement (-1 means _all_
	 * rows)
	 */
	protected int maxRows = -1;

	/** Has someone changed this for this statement? */
	protected boolean maxRowsChanged = false;

	/** Set of currently-open ResultSets */
	protected Set openResults = new HashSet();

	/** Are we in pedantic mode? */
	protected boolean pedantic = false;

	/**
	 * Where this statement was created, only used if profileSql or
	 * useUsageAdvisor set to true.
	 */
	protected Throwable pointOfOrigin;

	/** Should we profile? */
	protected boolean profileSQL = false;

	/** The current results */
	protected ResultSetInternalMethods results = null;

	/** The concurrency for this result set (updatable or not) */
	protected int resultSetConcurrency = 0;

	/** The type of this result set (scroll sensitive or in-sensitive) */
	protected int resultSetType = 0;

	/** Used to identify this statement when profiling. */
	protected int statementId;

	/** The timeout for a query */
	protected int timeoutInMillis = 0;

	/** The update count for this statement */
	protected long updateCount = -1;

	/** Should we use the usage advisor? */
	protected boolean useUsageAdvisor = false;

	/** The warnings chain. */
	protected SQLWarning warningChain = null;

	/**
	 * Should this statement hold results open over .close() irregardless of
	 * connection's setting?
	 */
	protected boolean holdResultsOpenOverClose = false;

	protected ArrayList batchedGeneratedKeys = null;

	protected boolean retrieveGeneratedKeys = false;

	protected boolean continueBatchOnError = false;

	protected PingTarget pingTarget = null;
	
	protected boolean useLegacyDatetimeCode;
	
	private ExceptionInterceptor exceptionInterceptor;
	
	/** Whether or not the last query was of the form ON DUPLICATE KEY UPDATE */
	protected boolean lastQueryIsOnDupKeyUpdate = false;
	
	/**
	 * Constructor for a Statement.
	 *
	 * @param c
	 *            the Connection instantation that creates us
	 * @param catalog
	 *            the database name in use when we were created
	 *
	 * @throws SQLException
	 *             if an error occurs.
	 */
	public StatementImpl(MySQLConnection c, String catalog) throws SQLException {
		if ((c == null) || c.isClosed()) {
			throw SQLError.createSQLException(
					Messages.getString("Statement.0"), //$NON-NLS-1$
					SQLError.SQL_STATE_CONNECTION_NOT_OPEN, null); //$NON-NLS-1$ //$NON-NLS-2$
		}

		this.connection = c;
		this.connectionId = this.connection.getId();
		this.exceptionInterceptor = this.connection
				.getExceptionInterceptor();

		this.currentCatalog = catalog;
		this.pedantic = this.connection.getPedantic();
		this.continueBatchOnError = this.connection.getContinueBatchOnError();
		this.useLegacyDatetimeCode = this.connection.getUseLegacyDatetimeCode();
		
		if (!this.connection.getDontTrackOpenResources()) {
			this.connection.registerStatement(this);
		}

		//
		// Adjust, if we know it
		//

		if (this.connection != null) {
			this.maxFieldSize = this.connection.getMaxAllowedPacket();

			int defaultFetchSize = this.connection.getDefaultFetchSize();

			if (defaultFetchSize != 0) {
				setFetchSize(defaultFetchSize);
			}
		}

		if (this.connection.getUseUnicode()) {
			this.charEncoding = this.connection.getEncoding();

			this.charConverter = this.connection.getCharsetConverter(this.charEncoding);
		}

		boolean profiling = this.connection.getProfileSql()
				|| this.connection.getUseUsageAdvisor() || this.connection.getLogSlowQueries();

		if (this.connection.getAutoGenerateTestcaseScript() || profiling) {
			this.statementId = statementCounter++;
		}

		if (profiling) {
			this.pointOfOrigin = new Throwable();
			this.profileSQL = this.connection.getProfileSql();
			this.useUsageAdvisor = this.connection.getUseUsageAdvisor();
			this.eventSink = ProfilerEventHandlerFactory.getInstance(this.connection);
		}

		int maxRowsConn = this.connection.getMaxRows();

		if (maxRowsConn != -1) {
			setMaxRows(maxRowsConn);
		}
		
		this.holdResultsOpenOverClose = this.connection.getHoldResultsOpenOverStatementClose();
	}

	/**
	 * DOCUMENT ME!
	 *
	 * @param sql
	 *            DOCUMENT ME!
	 *
	 * @throws SQLException
	 *             DOCUMENT ME!
	 */
	public synchronized void addBatch(String sql) throws SQLException {
		if (this.batchedArgs == null) {
			this.batchedArgs = new ArrayList();
		}

		if (sql != null) {
			this.batchedArgs.add(sql);
		}
	}

	/**
	 * Cancels this Statement object if both the DBMS and driver support
	 * aborting an SQL statement. This method can be used by one thread to
	 * cancel a statement that is being executed by another thread.
	 */
	public void cancel() throws SQLException {
		if (!this.isClosed &&
				this.connection != null &&
				this.connection.versionMeetsMinimum(5, 0, 0)) {
			Connection cancelConn = null;
			java.sql.Statement cancelStmt = null;

			try {
				cancelConn = this.connection.duplicate();
				cancelStmt = cancelConn.createStatement();
				cancelStmt.execute("KILL QUERY "
						+ this.connection.getIO().getThreadId());
				this.wasCancelled = true;
			} finally {
				if (cancelStmt != null) {
					cancelStmt.close();
				}

				if (cancelConn != null) {
					cancelConn.close();
				}
			}

		}
	}

	// --------------------------JDBC 2.0-----------------------------

	/**
	 * Checks if closed() has been called, and throws an exception if so
	 *
	 * @throws SQLException
	 *             if this statement has been closed
	 */
	protected void checkClosed() throws SQLException {
		if (this.isClosed) {
			throw SQLError.createSQLException(Messages
					.getString("Statement.49"), //$NON-NLS-1$
					SQLError.SQL_STATE_CONNECTION_NOT_OPEN, getExceptionInterceptor()); //$NON-NLS-1$
		}
	}

	/**
	 * Checks if the given SQL query with the given first non-ws char is a DML
	 * statement. Throws an exception if it is.
	 *
	 * @param sql
	 *            the SQL to check
	 * @param firstStatementChar
	 *            the UC first non-ws char of the statement
	 *
	 * @throws SQLException
	 *             if the statement contains DML
	 */
	protected void checkForDml(String sql, char firstStatementChar)
			throws SQLException {
		if ((firstStatementChar == 'I') || (firstStatementChar == 'U')
				|| (firstStatementChar == 'D') || (firstStatementChar == 'A')
				|| (firstStatementChar == 'C')) {
			String noCommentSql = StringUtils.stripComments(sql,
					"'\"", "'\"", true, false, true, true);

			if (StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "INSERT") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "UPDATE") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "DELETE") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "DROP") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "CREATE") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "ALTER")) { //$NON-NLS-1$
				throw SQLError.createSQLException(Messages
						.getString("Statement.57"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
			}
		}
	}

	/**
	 * Method checkNullOrEmptyQuery.
	 *
	 * @param sql
	 *            the SQL to check
	 *
	 * @throws SQLException
	 *             if query is null or empty.
	 */
	protected void checkNullOrEmptyQuery(String sql) throws SQLException {
		if (sql == null) {
			throw SQLError.createSQLException(Messages
					.getString("Statement.59"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$ //$NON-NLS-2$
		}

		if (sql.length() == 0) {
			throw SQLError.createSQLException(Messages
					.getString("Statement.61"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$ //$NON-NLS-2$
		}
	}

	/**
	 * JDBC 2.0 Make the set of commands in the current batch empty. This method
	 * is optional.
	 *
	 * @exception SQLException
	 *                if a database-access error occurs, or the driver does not
	 *                support batch statements
	 */
	public synchronized void clearBatch() throws SQLException {
		if (this.batchedArgs != null) {
			this.batchedArgs.clear();
		}
	}

	/**
	 * After this call, getWarnings returns null until a new warning is reported
	 * for this Statement.
	 *
	 * @exception SQLException
	 *                if a database access error occurs (why?)
	 */
	public void clearWarnings() throws SQLException {
		this.warningChain = null;
	}

	/**
	 * In many cases, it is desirable to immediately release a Statement's
	 * database and JDBC resources instead of waiting for this to happen when it
	 * is automatically closed. The close method provides this immediate
	 * release.
	 *
	 * <p>
	 * <B>Note:</B> A Statement is automatically closed when it is garbage
	 * collected. When a Statement is closed, its current ResultSet, if one
	 * exists, is also closed.
	 * </p>
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public synchronized void close() throws SQLException {
		realClose(true, true);
	}

	/**
	 * Close any open result sets that have been 'held open'
	 */
	protected synchronized void closeAllOpenResults() {
		if (this.openResults != null) {
			for (Iterator iter = this.openResults.iterator(); iter.hasNext();) {
				ResultSetInternalMethods element = (ResultSetInternalMethods) iter.next();

				try {
					element.realClose(false);
				} catch (SQLException sqlEx) {
					AssertionFailedException.shouldNotHappen(sqlEx);
				}
			}

			this.openResults.clear();
		}
	}

	public synchronized void removeOpenResultSet(ResultSet rs) {
		if (this.openResults != null) {
			this.openResults.remove(rs);
		}
	}
	
	public synchronized int getOpenResultSetCount() {
		if (this.openResults != null) {
			return this.openResults.size();
		}
		
		return 0;
	}
	
	/**
	 * @param sql
	 * @return
	 */
	private ResultSetInternalMethods createResultSetUsingServerFetch(String sql)
			throws SQLException {
		java.sql.PreparedStatement pStmt = this.connection.prepareStatement(
				sql, this.resultSetType, this.resultSetConcurrency);

		pStmt.setFetchSize(this.fetchSize);

		if (this.maxRows > -1) {
			pStmt.setMaxRows(this.maxRows);
		}

		pStmt.execute();

		//
		// Need to be able to get resultset irrespective if we issued DML or
		// not to make this work.
		//
		ResultSetInternalMethods rs = ((com.mysql.jdbc.StatementImpl) pStmt)
				.getResultSetInternal();

		rs
				.setStatementUsedForFetchingRows((com.mysql.jdbc.PreparedStatement) pStmt);

		this.results = rs;

		return rs;
	}

	/**
	 * We only stream result sets when they are forward-only, read-only, and the
	 * fetch size has been set to Integer.MIN_VALUE
	 *
	 * @return true if this result set should be streamed row at-a-time, rather
	 *         than read all at once.
	 */
	protected boolean createStreamingResultSet() {
		return ((this.resultSetType == java.sql.ResultSet.TYPE_FORWARD_ONLY)
				&& (this.resultSetConcurrency == java.sql.ResultSet.CONCUR_READ_ONLY) && (this.fetchSize == Integer.MIN_VALUE));
	}

	private int originalResultSetType = 0;
	private int originalFetchSize = 0;

	/* (non-Javadoc)
	 * @see com.mysql.jdbc.IStatement#enableStreamingResults()
	 */
	public void enableStreamingResults() throws SQLException {
		this.originalResultSetType = this.resultSetType;
		this.originalFetchSize = this.fetchSize;

		setFetchSize(Integer.MIN_VALUE);
		setResultSetType(ResultSet.TYPE_FORWARD_ONLY);
	}

	public void disableStreamingResults() throws SQLException {
		if (this.fetchSize == Integer.MIN_VALUE &&
				this.resultSetType == ResultSet.TYPE_FORWARD_ONLY) {
			setFetchSize(this.originalFetchSize);
			setResultSetType(this.originalResultSetType);
		}
	}

	/**
	 * Execute a SQL statement that may return multiple results. We don't have
	 * to worry about this since we do not support multiple ResultSets. You can
	 * use getResultSet or getUpdateCount to retrieve the result.
	 *
	 * @param sql
	 *            any SQL statement
	 *
	 * @return true if the next result is a ResulSet, false if it is an update
	 *         count or there are no more results
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public boolean execute(String sql) throws SQLException {
		return execute(sql, false);
	}
	
	private boolean execute(String sql, boolean returnGeneratedKeys) throws SQLException {
		checkClosed();

		MySQLConnection locallyScopedConn = this.connection;

		synchronized (locallyScopedConn.getMutex()) {
			this.retrieveGeneratedKeys = returnGeneratedKeys;
			lastQueryIsOnDupKeyUpdate = false;
			if (returnGeneratedKeys)
				lastQueryIsOnDupKeyUpdate = containsOnDuplicateKeyInString(sql);
			
			resetCancelledState();

			checkNullOrEmptyQuery(sql);

			checkClosed();

			char firstNonWsChar = StringUtils.firstAlphaCharUc(sql, findStartOfStatement(sql));

			boolean isSelect = true;

			if (firstNonWsChar != 'S') {
				isSelect = false;

				if (locallyScopedConn.isReadOnly()) {
					throw SQLError.createSQLException(Messages
							.getString("Statement.27") //$NON-NLS-1$
							+ Messages.getString("Statement.28"), //$NON-NLS-1$
							SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
				}
			}

			boolean doStreaming = createStreamingResultSet();

			// Adjust net_write_timeout to a higher value if we're
			// streaming result sets. More often than not, someone runs into
			// an issue where they blow net_write_timeout when using this
			// feature, and if they're willing to hold a result set open
			// for 30 seconds or more, one more round-trip isn't going to hurt
			//
			// This is reset by RowDataDynamic.close().

			if (doStreaming
					&& locallyScopedConn.getNetTimeoutForStreamingResults() > 0) {
				executeSimpleNonQuery(locallyScopedConn, "SET net_write_timeout="
						+ locallyScopedConn.getNetTimeoutForStreamingResults());
			}

			if (this.doEscapeProcessing) {
				Object escapedSqlResult = EscapeProcessor.escapeSQL(sql,
						locallyScopedConn.serverSupportsConvertFn(), locallyScopedConn);

				if (escapedSqlResult instanceof String) {
					sql = (String) escapedSqlResult;
				} else {
					sql = ((EscapeProcessorResult) escapedSqlResult).escapedSql;
				}
			}

			if (this.results != null) {
				if (!locallyScopedConn.getHoldResultsOpenOverStatementClose()) {
					this.results.realClose(false);
				}
			}

			if (sql.charAt(0) == '/') {
				if (sql.startsWith(PING_MARKER)) {
					doPingInstead();
				
					return true;
				}
			}

			CachedResultSetMetaData cachedMetaData = null;

			ResultSetInternalMethods rs = null;

			// If there isn't a limit clause in the SQL
			// then limit the number of rows to return in
			// an efficient manner. Only do this if
			// setMaxRows() hasn't been used on any Statements
			// generated from the current Connection (saves
			// a query, and network traffic).

			this.batchedGeneratedKeys = null;

			if (useServerFetch()) {
				rs = createResultSetUsingServerFetch(sql);
			} else {
				CancelTask timeoutTask = null;

				String oldCatalog = null;

				try {
					if (locallyScopedConn.getEnableQueryTimeouts() &&
							this.timeoutInMillis != 0
							&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
						timeoutTask = new CancelTask(this);
						locallyScopedConn.getCancelTimer().schedule(timeoutTask,
								this.timeoutInMillis);
					}



					if (!locallyScopedConn.getCatalog().equals(
							this.currentCatalog)) {
						oldCatalog = locallyScopedConn.getCatalog();
						locallyScopedConn.setCatalog(this.currentCatalog);
					}

					//
					// Check if we have cached metadata for this query...
					//

					Field[] cachedFields = null;

					if (locallyScopedConn.getCacheResultSetMetadata()) {
						cachedMetaData = locallyScopedConn.getCachedMetaData(sql);

						if (cachedMetaData != null) {
							cachedFields = cachedMetaData.fields;
						}
					}

					//
					// Only apply max_rows to selects
					//
					if (locallyScopedConn.useMaxRows()) {
						int rowLimit = -1;

						if (isSelect) {
							if (StringUtils.indexOfIgnoreCase(sql, "LIMIT") != -1) { //$NON-NLS-1$
								rowLimit = this.maxRows;
							} else {
								if (this.maxRows <= 0) {
									executeSimpleNonQuery(locallyScopedConn,
											"SET OPTION SQL_SELECT_LIMIT=DEFAULT");
								} else {
									executeSimpleNonQuery(locallyScopedConn,
											"SET OPTION SQL_SELECT_LIMIT="
													+ this.maxRows);
								}
							}
						} else {
							executeSimpleNonQuery(locallyScopedConn,
									"SET OPTION SQL_SELECT_LIMIT=DEFAULT");
						}

						// Finally, execute the query
						rs = locallyScopedConn.execSQL(this, sql, rowLimit, null,
								this.resultSetType, this.resultSetConcurrency,
								doStreaming,
								this.currentCatalog, cachedFields);
					} else {
						rs = locallyScopedConn.execSQL(this, sql, -1, null,
								this.resultSetType, this.resultSetConcurrency,
								doStreaming,
								this.currentCatalog, cachedFields);
					}

					if (timeoutTask != null) {
						if (timeoutTask.caughtWhileCancelling != null) {
							throw timeoutTask.caughtWhileCancelling;
						}

						timeoutTask.cancel();
						timeoutTask = null;
					}

					synchronized (this.cancelTimeoutMutex) {
						if (this.wasCancelled) {
							SQLException cause = null;
							
							if (this.wasCancelledByTimeout) {
								cause = new MySQLTimeoutException();
							} else {
								cause = new MySQLStatementCancelledException();
							}
							
							resetCancelledState();
							
							throw cause;
						}
					}
				} finally {
					if (timeoutTask != null) {
						timeoutTask.cancel();
						locallyScopedConn.getCancelTimer().purge();
					}

					if (oldCatalog != null) {
						locallyScopedConn.setCatalog(oldCatalog);
					}
				}
			}

			if (rs != null) {
				this.lastInsertId = rs.getUpdateID();

				this.results = rs;

				rs.setFirstCharOfQuery(firstNonWsChar);

				if (rs.reallyResult()) {
					if (cachedMetaData != null) {
						locallyScopedConn.initializeResultsMetadataFromCache(sql, cachedMetaData,
								this.results);
					} else {
						if (this.connection.getCacheResultSetMetadata()) {
							locallyScopedConn.initializeResultsMetadataFromCache(sql,
									null /* will be created */, this.results);
						}
					}
				}
			}

			return ((rs != null) && rs.reallyResult());
		}
	}

	protected synchronized void resetCancelledState() {
		if (this.cancelTimeoutMutex == null) {
			return;
		}
		
		synchronized (this.cancelTimeoutMutex) {
			this.wasCancelled = false;
			this.wasCancelledByTimeout = false;
		}
	}

	/**
	 * @see StatementImpl#execute(String, int)
	 */
	public boolean execute(String sql, int returnGeneratedKeys)
			throws SQLException {


		if (returnGeneratedKeys == java.sql.Statement.RETURN_GENERATED_KEYS) {
			checkClosed();

			MySQLConnection locallyScopedConn = this.connection;

			synchronized (locallyScopedConn.getMutex()) {
				// If this is a 'REPLACE' query, we need to be able to parse
				// the 'info' message returned from the server to determine
				// the actual number of keys generated.
				boolean readInfoMsgState = this.connection
						.isReadInfoMsgEnabled();
				locallyScopedConn.setReadInfoMsgEnabled(true);

				try {
					return execute(sql, true);
				} finally {
					locallyScopedConn.setReadInfoMsgEnabled(readInfoMsgState);
				}
			}
		}

		return execute(sql);
	}

	/**
	 * @see StatementImpl#execute(String, int[])
	 */
	public boolean execute(String sql, int[] generatedKeyIndices)
			throws SQLException {
		if ((generatedKeyIndices != null) && (generatedKeyIndices.length > 0)) {
			checkClosed();

			MySQLConnection locallyScopedConn = this.connection;

			synchronized (locallyScopedConn.getMutex()) {
				this.retrieveGeneratedKeys = true;
				
				// If this is a 'REPLACE' query, we need to be able to parse
				// the 'info' message returned from the server to determine
				// the actual number of keys generated.
				boolean readInfoMsgState = locallyScopedConn
						.isReadInfoMsgEnabled();
				locallyScopedConn.setReadInfoMsgEnabled(true);

				try {
					return execute(sql, true);
				} finally {
					locallyScopedConn.setReadInfoMsgEnabled(readInfoMsgState);
				}
			}
		}

		return execute(sql);
	}

	/**
	 * @see StatementImpl#execute(String, String[])
	 */
	public boolean execute(String sql, String[] generatedKeyNames)
			throws SQLException {
		if ((generatedKeyNames != null) && (generatedKeyNames.length > 0)) {
			checkClosed();

			MySQLConnection locallyScopedConn = this.connection;

			synchronized (locallyScopedConn.getMutex()) {
				this.retrieveGeneratedKeys = true;
				// If this is a 'REPLACE' query, we need to be able to parse
				// the 'info' message returned from the server to determine
				// the actual number of keys generated.
				boolean readInfoMsgState = this.connection
						.isReadInfoMsgEnabled();
				locallyScopedConn.setReadInfoMsgEnabled(true);

				try {
					return execute(sql, true);
				} finally {
					locallyScopedConn.setReadInfoMsgEnabled(readInfoMsgState);
				}
			}
		}

		return execute(sql);
	}

	/**
	 * JDBC 2.0 Submit a batch of commands to the database for execution. This
	 * method is optional.
	 *
	 * @return an array of update counts containing one element for each command
	 *         in the batch. The array is ordered according to the order in
	 *         which commands were inserted into the batch
	 *
	 * @exception SQLException
	 *                if a database-access error occurs, or the driver does not
	 *                support batch statements
	 * @throws java.sql.BatchUpdateException
	 *             DOCUMENT ME!
	 */
	public synchronized int[] executeBatch() throws SQLException {
		checkClosed();

		MySQLConnection locallyScopedConn = this.connection;

		if (locallyScopedConn.isReadOnly()) {
			throw SQLError.createSQLException(Messages
					.getString("Statement.34") //$NON-NLS-1$
					+ Messages.getString("Statement.35"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
		}

		if (this.results != null) {
			if (!locallyScopedConn.getHoldResultsOpenOverStatementClose()) {
				this.results.realClose(false);
			}
		}

		synchronized (locallyScopedConn.getMutex()) {
			if (this.batchedArgs == null || this.batchedArgs.size() == 0) {
                return new int[0];
            }
			
			// we timeout the entire batch, not individual statements
			int individualStatementTimeout = this.timeoutInMillis;
			this.timeoutInMillis = 0;
			
			CancelTask timeoutTask = null;
			
			try {
				resetCancelledState();

				this.retrieveGeneratedKeys = true; // The JDBC spec doesn't forbid this, but doesn't provide for it either...we do..

				int[] updateCounts = null;

				
				if (this.batchedArgs != null) {
					int nbrCommands = this.batchedArgs.size();

					this.batchedGeneratedKeys = new ArrayList(this.batchedArgs.size());

					boolean multiQueriesEnabled = locallyScopedConn.getAllowMultiQueries();

					if (locallyScopedConn.versionMeetsMinimum(4, 1, 1) &&
							(multiQueriesEnabled ||
							(locallyScopedConn.getRewriteBatchedStatements() &&
									nbrCommands > 4))) {
						return executeBatchUsingMultiQueries(multiQueriesEnabled, nbrCommands, individualStatementTimeout);
					}

					if (locallyScopedConn.getEnableQueryTimeouts() &&
							individualStatementTimeout != 0
							&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
						timeoutTask = new CancelTask(this);
						locallyScopedConn.getCancelTimer().schedule(timeoutTask,
								individualStatementTimeout);
					}
					
					updateCounts = new int[nbrCommands];

					for (int i = 0; i < nbrCommands; i++) {
						updateCounts[i] = -3;
					}

					SQLException sqlEx = null;

					int commandIndex = 0;

					for (commandIndex = 0; commandIndex < nbrCommands; commandIndex++) {
						try {
							String sql = (String) this.batchedArgs.get(commandIndex);
							updateCounts[commandIndex] = executeUpdate(sql, true, true);
							// limit one generated key per OnDuplicateKey statement
							getBatchedGeneratedKeys(containsOnDuplicateKeyInString(sql) ? 1 : 0);
						} catch (SQLException ex) {
							updateCounts[commandIndex] = EXECUTE_FAILED;

							if (this.continueBatchOnError && 
									!(ex instanceof MySQLTimeoutException) && 
									!(ex instanceof MySQLStatementCancelledException) &&
                                    !hasDeadlockOrTimeoutRolledBackTx(ex)) {
								sqlEx = ex;
							} else {
								int[] newUpdateCounts = new int[commandIndex];
								
								if (hasDeadlockOrTimeoutRolledBackTx(ex)) {
									for (int i = 0; i < newUpdateCounts.length; i++) {
										newUpdateCounts[i] = Statement.EXECUTE_FAILED;
									}
								} else {
									System.arraycopy(updateCounts, 0,
										newUpdateCounts, 0, commandIndex);
								}

								throw new java.sql.BatchUpdateException(ex
										.getMessage(), ex.getSQLState(), ex
										.getErrorCode(), newUpdateCounts);
							}
						}
					}

					if (sqlEx != null) {
						throw new java.sql.BatchUpdateException(sqlEx
								.getMessage(), sqlEx.getSQLState(), sqlEx
								.getErrorCode(), updateCounts);
					}
				}

				if (timeoutTask != null) {
					if (timeoutTask.caughtWhileCancelling != null) {
						throw timeoutTask.caughtWhileCancelling;
					}

					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
					timeoutTask = null;
				}
				
				return (updateCounts != null) ? updateCounts : new int[0];
			} finally {
				
				if (timeoutTask != null) {
					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
				}
				
				resetCancelledState();
				
				this.timeoutInMillis = individualStatementTimeout;

				clearBatch();
			}
		}
	}

	protected final boolean hasDeadlockOrTimeoutRolledBackTx(SQLException ex) {
		int vendorCode = ex.getErrorCode();
		
		switch (vendorCode) {
		case MysqlErrorNumbers.ER_LOCK_DEADLOCK:
		case MysqlErrorNumbers.ER_LOCK_TABLE_FULL:
			return true;
		case MysqlErrorNumbers.ER_LOCK_WAIT_TIMEOUT:
			try {
				return !this.connection.versionMeetsMinimum(5, 0, 13);
			} catch (SQLException sqlEx) {
				// won't actually be thrown in this case
				return false;
			}
		default:
			return false;
		}
	}

	/**
	 * Rewrites batch into a single query to send to the server. This method
	 * will constrain each batch to be shorter than max_allowed_packet on the
	 * server.
	 *
	 * @return update counts in the same manner as executeBatch()
	 * @throws SQLException
	 */
	private int[] executeBatchUsingMultiQueries(boolean multiQueriesEnabled,
			int nbrCommands, int individualStatementTimeout) throws SQLException {

		MySQLConnection locallyScopedConn = this.connection;

		if (!multiQueriesEnabled) {
			locallyScopedConn.getIO().enableMultiQueries();
		}

		java.sql.Statement batchStmt = null;

		CancelTask timeoutTask = null;
		
		try {
			int[] updateCounts = new int[nbrCommands];

			for (int i = 0; i < nbrCommands; i++) {
				updateCounts[i] = -3;
			}

			int commandIndex = 0;

			StringBuffer queryBuf = new StringBuffer();

			batchStmt = locallyScopedConn.createStatement();

			if (locallyScopedConn.getEnableQueryTimeouts() &&
					individualStatementTimeout != 0
					&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
				timeoutTask = new CancelTask((StatementImpl)batchStmt);
				locallyScopedConn.getCancelTimer().schedule(timeoutTask,
						individualStatementTimeout);
			}
			
			int counter = 0;

			int numberOfBytesPerChar = 1;

			String connectionEncoding = locallyScopedConn.getEncoding();

			if (StringUtils.startsWithIgnoreCase(connectionEncoding, "utf")) {
				numberOfBytesPerChar = 3;
			} else if (CharsetMapping.isMultibyteCharset(connectionEncoding)) {
				numberOfBytesPerChar = 2;
			}

			int escapeAdjust = 1;

			batchStmt.setEscapeProcessing(this.doEscapeProcessing);
			
			if (this.doEscapeProcessing) {
				
				escapeAdjust = 2; /* We assume packet _could_ grow by this amount, as we're not
				                     sure how big statement will end up after
				                     escape processing */
			}

			SQLException sqlEx = null;
			
			int argumentSetsInBatchSoFar = 0;
			
			for (commandIndex = 0; commandIndex < nbrCommands; commandIndex++) {
				String nextQuery = (String) this.batchedArgs.get(commandIndex);

				if (((((queryBuf.length() + nextQuery.length())
						* numberOfBytesPerChar) + 1 /* for semicolon */
						+ MysqlIO.HEADER_LENGTH) * escapeAdjust)  + 32 > this.connection
						.getMaxAllowedPacket()) {
					try {
						batchStmt.execute(queryBuf.toString(), Statement.RETURN_GENERATED_KEYS);
					} catch (SQLException ex) {
						sqlEx = handleExceptionForBatch(commandIndex,
								argumentSetsInBatchSoFar, updateCounts, ex);
					}

					counter = processMultiCountsAndKeys((StatementImpl)batchStmt, counter, 
							updateCounts);

					queryBuf = new StringBuffer();
					argumentSetsInBatchSoFar = 0;
				}

				queryBuf.append(nextQuery);
				queryBuf.append(";");
				argumentSetsInBatchSoFar++;
			}

			if (queryBuf.length() > 0) {
				try {
					batchStmt.execute(queryBuf.toString(), Statement.RETURN_GENERATED_KEYS);
				} catch (SQLException ex) {
					sqlEx = handleExceptionForBatch(commandIndex - 1,
							argumentSetsInBatchSoFar, updateCounts, ex);
				}

				counter = processMultiCountsAndKeys((StatementImpl)batchStmt, counter, 
						updateCounts);
			}

			if (timeoutTask != null) {
				if (timeoutTask.caughtWhileCancelling != null) {
					throw timeoutTask.caughtWhileCancelling;
				}

				timeoutTask.cancel();
				
				locallyScopedConn.getCancelTimer().purge();
				
				timeoutTask = null;
			}
			
			if (sqlEx != null) {
				throw new java.sql.BatchUpdateException(sqlEx
						.getMessage(), sqlEx.getSQLState(), sqlEx
						.getErrorCode(), updateCounts);
			}
			
			return (updateCounts != null) ? updateCounts : new int[0];
		} finally {
			if (timeoutTask != null) {
				timeoutTask.cancel();
				
				locallyScopedConn.getCancelTimer().purge();
			}
			
			resetCancelledState();
			
			try {
				if (batchStmt != null) {
					batchStmt.close();
				}
			} finally {
				if (!multiQueriesEnabled) {
					locallyScopedConn.getIO().disableMultiQueries();
				}
			}
		}
	}
	
	protected int processMultiCountsAndKeys(
			StatementImpl batchedStatement,
			int updateCountCounter, int[] updateCounts) throws SQLException {
		updateCounts[updateCountCounter++] = batchedStatement.getUpdateCount();
		
		boolean doGenKeys = this.batchedGeneratedKeys != null;

		byte[][] row = null;
		
		if (doGenKeys) {
			long generatedKey = batchedStatement.getLastInsertID();
		
			row = new byte[1][];
			row[0] = Long.toString(generatedKey).getBytes();
			this.batchedGeneratedKeys.add(new ByteArrayRow(row, getExceptionInterceptor()));
		}

		while (batchedStatement.getMoreResults()
				|| batchedStatement.getUpdateCount() != -1) {
			updateCounts[updateCountCounter++] = batchedStatement.getUpdateCount();
			
			if (doGenKeys) {
				long generatedKey = batchedStatement.getLastInsertID();
				
				row = new byte[1][];
				row[0] = Long.toString(generatedKey).getBytes();
				this.batchedGeneratedKeys.add(new ByteArrayRow(row, getExceptionInterceptor()));
			}
		}
		
		return updateCountCounter;
	}
	
	protected SQLException handleExceptionForBatch(int endOfBatchIndex,
			int numValuesPerBatch, int[] updateCounts, SQLException ex)
			throws BatchUpdateException {
		SQLException sqlEx;
	
		for (int j = endOfBatchIndex; j > endOfBatchIndex - numValuesPerBatch; j--) {
			updateCounts[j] = EXECUTE_FAILED;
		}

		if (this.continueBatchOnError && 
				!(ex instanceof MySQLTimeoutException) && 
				!(ex instanceof MySQLStatementCancelledException) &&
				!hasDeadlockOrTimeoutRolledBackTx(ex)) {
			sqlEx = ex;
		} else {
			int[] newUpdateCounts = new int[endOfBatchIndex];
			System.arraycopy(updateCounts, 0,
					newUpdateCounts, 0, endOfBatchIndex);

			throw new java.sql.BatchUpdateException(ex
					.getMessage(), ex.getSQLState(), ex
					.getErrorCode(), newUpdateCounts);
		}
		
		return sqlEx;
	}
	
	/**
	 * Execute a SQL statement that retruns a single ResultSet
	 *
	 * @param sql
	 *            typically a static SQL SELECT statement
	 *
	 * @return a ResulSet that contains the data produced by the query
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public java.sql.ResultSet executeQuery(String sql)
			throws SQLException {
		checkClosed();

		MySQLConnection locallyScopedConn = this.connection;

		synchronized (locallyScopedConn.getMutex()) {
			this.retrieveGeneratedKeys = false;
			
			resetCancelledState();

			checkNullOrEmptyQuery(sql);

			boolean doStreaming = createStreamingResultSet();

			// Adjust net_write_timeout to a higher value if we're
			// streaming result sets. More often than not, someone runs into
			// an issue where they blow net_write_timeout when using this
			// feature, and if they're willing to hold a result set open
			// for 30 seconds or more, one more round-trip isn't going to hurt
			//
			// This is reset by RowDataDynamic.close().

			if (doStreaming
					&& this.connection.getNetTimeoutForStreamingResults() > 0) {
				executeSimpleNonQuery(locallyScopedConn, "SET net_write_timeout="
						+ this.connection.getNetTimeoutForStreamingResults());
			}

			if (this.doEscapeProcessing) {
				Object escapedSqlResult = EscapeProcessor.escapeSQL(sql,
						locallyScopedConn.serverSupportsConvertFn(), this.connection);

				if (escapedSqlResult instanceof String) {
					sql = (String) escapedSqlResult;
				} else {
					sql = ((EscapeProcessorResult) escapedSqlResult).escapedSql;
				}
			}

			char firstStatementChar = StringUtils.firstNonWsCharUc(sql,
					findStartOfStatement(sql));

			if (sql.charAt(0) == '/') {
				if (sql.startsWith(PING_MARKER)) {
					doPingInstead();
				
					return this.results;
				}
			}
			
			checkForDml(sql, firstStatementChar);

			if (this.results != null) {
				if (!locallyScopedConn.getHoldResultsOpenOverStatementClose()) {
					this.results.realClose(false);
				}
			}

			CachedResultSetMetaData cachedMetaData = null;

			// If there isn't a limit clause in the SQL
			// then limit the number of rows to return in
			// an efficient manner. Only do this if
			// setMaxRows() hasn't been used on any Statements
			// generated from the current Connection (saves
			// a query, and network traffic).

			if (useServerFetch()) {
				this.results = createResultSetUsingServerFetch(sql);

				return this.results;
			}

			CancelTask timeoutTask = null;

			String oldCatalog = null;

			try {
				if (locallyScopedConn.getEnableQueryTimeouts() &&
						this.timeoutInMillis != 0
						&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
					timeoutTask = new CancelTask(this);
					locallyScopedConn.getCancelTimer().schedule(timeoutTask,
							this.timeoutInMillis);
				}

				if (!locallyScopedConn.getCatalog().equals(this.currentCatalog)) {
					oldCatalog = locallyScopedConn.getCatalog();
					locallyScopedConn.setCatalog(this.currentCatalog);
				}

				//
				// Check if we have cached metadata for this query...
				//

				Field[] cachedFields = null;

				if (locallyScopedConn.getCacheResultSetMetadata()) {
					cachedMetaData = locallyScopedConn.getCachedMetaData(sql);

					if (cachedMetaData != null) {
						cachedFields = cachedMetaData.fields;
					}
				}

				if (locallyScopedConn.useMaxRows()) {
					// We need to execute this all together
					// So synchronize on the Connection's mutex (because
					// even queries going through there synchronize
					// on the connection
					if (StringUtils.indexOfIgnoreCase(sql, "LIMIT") != -1) { //$NON-NLS-1$
						this.results = locallyScopedConn.execSQL(this, sql,
								this.maxRows, null, this.resultSetType,
								this.resultSetConcurrency,
								doStreaming,
								this.currentCatalog, cachedFields);
					} else {
						if (this.maxRows <= 0) {
							executeSimpleNonQuery(locallyScopedConn,
									"SET OPTION SQL_SELECT_LIMIT=DEFAULT");
						} else {
							executeSimpleNonQuery(locallyScopedConn,
											"SET OPTION SQL_SELECT_LIMIT=" + this.maxRows);
						}

						this.results = locallyScopedConn.execSQL(this, sql, -1,
								null, this.resultSetType,
								this.resultSetConcurrency,
								doStreaming,
								this.currentCatalog, cachedFields);

						if (oldCatalog != null) {
							locallyScopedConn.setCatalog(oldCatalog);
						}
					}
				} else {
					this.results = locallyScopedConn.execSQL(this, sql, -1, null,
							this.resultSetType, this.resultSetConcurrency,
							doStreaming,
							this.currentCatalog, cachedFields);
				}

				if (timeoutTask != null) {
					if (timeoutTask.caughtWhileCancelling != null) {
						throw timeoutTask.caughtWhileCancelling;
					}

					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
					
					timeoutTask = null;
				}

				synchronized (this.cancelTimeoutMutex) {
					if (this.wasCancelled) {
						SQLException cause = null;
						
						if (this.wasCancelledByTimeout) {
							cause = new MySQLTimeoutException();
						} else {
							cause = new MySQLStatementCancelledException();
						}
						
						resetCancelledState();
						
						throw cause;
					}
				}
			} finally {
				if (timeoutTask != null) {
					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
				}

				if (oldCatalog != null) {
					locallyScopedConn.setCatalog(oldCatalog);
				}
			}

			this.lastInsertId = this.results.getUpdateID();

			if (cachedMetaData != null) {
				locallyScopedConn.initializeResultsMetadataFromCache(sql, cachedMetaData,
						this.results);
			} else {
				if (this.connection.getCacheResultSetMetadata()) {
					locallyScopedConn.initializeResultsMetadataFromCache(sql,
							null /* will be created */, this.results);
				}
			}

			return this.results;
		}
	}

	protected void doPingInstead() throws SQLException {
		if (this.pingTarget != null) {
			this.pingTarget.doPing();
		} else {
			this.connection.ping();
		}

		ResultSetInternalMethods fakeSelectOneResultSet = generatePingResultSet();
		this.results = fakeSelectOneResultSet;
	}

	protected ResultSetInternalMethods generatePingResultSet() throws SQLException {
		Field[] fields = { new Field(null, "1", Types.BIGINT, 1) };
		ArrayList rows = new ArrayList();
		byte[] colVal = new byte[] { (byte) '1' };

		rows.add(new ByteArrayRow(new byte[][] { colVal }, getExceptionInterceptor()));

		return (ResultSetInternalMethods) DatabaseMetaData.buildResultSet(fields, rows,
				this.connection);
	}
	
	protected void executeSimpleNonQuery(MySQLConnection c, String nonQuery)
			throws SQLException {
		c.execSQL(this, nonQuery,
				-1, null, ResultSet.TYPE_FORWARD_ONLY,
				ResultSet.CONCUR_READ_ONLY, false, this.currentCatalog,
				null, false).close();
	}

	/**
	 * Execute a SQL INSERT, UPDATE or DELETE statement. In addition SQL
	 * statements that return nothing such as SQL DDL statements can be executed
	 * Any IDs generated for AUTO_INCREMENT fields can be retrieved by casting
	 * this Statement to org.gjt.mm.mysql.Statement and calling the
	 * getLastInsertID() method.
	 *
	 * @param sql
	 *            a SQL statement
	 *
	 * @return either a row count, or 0 for SQL commands
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public int executeUpdate(String sql) throws SQLException {
		return executeUpdate(sql, false, false);
	}

	protected int executeUpdate(String sql, boolean isBatch, boolean returnGeneratedKeys)
		throws SQLException {
		checkClosed();

		MySQLConnection locallyScopedConn = this.connection;

		char firstStatementChar = StringUtils.firstAlphaCharUc(sql,
				findStartOfStatement(sql));

		ResultSetInternalMethods rs = null;

		synchronized (locallyScopedConn.getMutex()) {
			this.retrieveGeneratedKeys = returnGeneratedKeys;
			
			resetCancelledState();

			checkNullOrEmptyQuery(sql);

			if (this.doEscapeProcessing) {
				Object escapedSqlResult = EscapeProcessor.escapeSQL(sql,
						this.connection.serverSupportsConvertFn(), this.connection);

				if (escapedSqlResult instanceof String) {
					sql = (String) escapedSqlResult;
				} else {
					sql = ((EscapeProcessorResult) escapedSqlResult).escapedSql;
				}
			}

			if (locallyScopedConn.isReadOnly()) {
				throw SQLError.createSQLException(Messages
						.getString("Statement.42") //$NON-NLS-1$
						+ Messages.getString("Statement.43"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
			}

			if (StringUtils.startsWithIgnoreCaseAndWs(sql, "select")) { //$NON-NLS-1$
				throw SQLError.createSQLException(Messages
						.getString("Statement.46"), //$NON-NLS-1$
				"01S03", getExceptionInterceptor()); //$NON-NLS-1$
			}

			if (this.results != null) {
				if (!locallyScopedConn.getHoldResultsOpenOverStatementClose()) {
					this.results.realClose(false);
				}
			}

			// The checking and changing of catalogs
			// must happen in sequence, so synchronize
			// on the same mutex that _conn is using

			CancelTask timeoutTask = null;

			String oldCatalog = null;

			try {
				if (locallyScopedConn.getEnableQueryTimeouts() &&
						this.timeoutInMillis != 0
						&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
					timeoutTask = new CancelTask(this);
					locallyScopedConn.getCancelTimer().schedule(timeoutTask,
							this.timeoutInMillis);
				}

				if (!locallyScopedConn.getCatalog().equals(this.currentCatalog)) {
					oldCatalog = locallyScopedConn.getCatalog();
					locallyScopedConn.setCatalog(this.currentCatalog);
				}

				//
				// Only apply max_rows to selects
				//
				if (locallyScopedConn.useMaxRows()) {
					executeSimpleNonQuery(locallyScopedConn,
							"SET OPTION SQL_SELECT_LIMIT=DEFAULT");
				}

				rs = locallyScopedConn.execSQL(this, sql, -1, null,
						java.sql.ResultSet.TYPE_FORWARD_ONLY,
						java.sql.ResultSet.CONCUR_READ_ONLY, false,
						this.currentCatalog,
						null /* force read of field info on DML */,
						isBatch);

				if (timeoutTask != null) {
					if (timeoutTask.caughtWhileCancelling != null) {
						throw timeoutTask.caughtWhileCancelling;
					}

					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
					
					timeoutTask = null;
				}

				synchronized (this.cancelTimeoutMutex) {
					if (this.wasCancelled) {
						SQLException cause = null;
						
						if (this.wasCancelledByTimeout) {
							cause = new MySQLTimeoutException();
						} else {
							cause = new MySQLStatementCancelledException();
						}
						
						resetCancelledState();
						
						throw cause;
					}
				}
			} finally {
				if (timeoutTask != null) {
					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
				}

				if (oldCatalog != null) {
					locallyScopedConn.setCatalog(oldCatalog);
				}
			}
		}

		this.results = rs;

		rs.setFirstCharOfQuery(firstStatementChar);

		this.updateCount = rs.getUpdateCount();

		int truncatedUpdateCount = 0;

		if (this.updateCount > Integer.MAX_VALUE) {
			truncatedUpdateCount = Integer.MAX_VALUE;
		} else {
			truncatedUpdateCount = (int) this.updateCount;
		}

		this.lastInsertId = rs.getUpdateID();

		return truncatedUpdateCount;
	}


	/**
	 * @see StatementImpl#executeUpdate(String, int)
	 */
	public int executeUpdate(String sql, int returnGeneratedKeys)
			throws SQLException {
		if (returnGeneratedKe…