1. MySQL Connector/J

1.1. Basic JDBC concepts
1.2. Installing Connector/J
1.3. JDBC Reference
1.4. Using Connector/J with J2EE and Other Java Frameworks
1.5. Diagnosing Connector/J Problems
1.6. Changelog

MySQL provides connectivity for client applications developed in the Java programming language via a JDBC driver, which is called MySQL Connector/J.

MySQL Connector/J is a JDBC-3.0 "Type 4" driver, which means that is is pure Java, implements version 3.0 of the JDBC specification, and communicates directly with the MySQL server using the MySQL protocol.

This document is arranged for a beginning JDBC developer. If you are already experienced with using JDBC, you might consider starting with the section "Installing Connector/J".

While JDBC is useful by itself, we would hope that if you are not familiar with JDBC that after reading the first few sections of this manual, that you would avoid using "naked" JDBC for all but the most trivial problems and consider using one of the popular persistence frameworks such as Hibernate, Spring's JDBC templates or Ibatis SQL Maps to do the majority of repetitive work and heavier lifting that is sometimes required with JDBC.

This section is not designed to be a complete JDBC tutorial. If you need more information about using JDBC you might be interested in the following online tutorials that are more in-depth than the information presented here:

1.1. Basic JDBC concepts

This section provides some general JDBC background.

1.1.1. Connecting to MySQL using the DriverManager Interface

When you are using JDBC outside of an application server, the DriverManager class manages the establishment of Connections.

The DriverManager needs to be told which JDBC drivers it should try to make Connections with. The easiest way to do this is to use Class.forName() on the class that implements the java.sql.Driver interface. With MySQL Connector/J, the name of this class is com.mysql.jdbc.Driver. With this method, you could use an external configuration file to supply the driver class name and driver parameters to use when connecting to a database.

The following section of Java code shows how you might register MySQL Connector/J from the main() method of your application:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

// Notice, do not import com.mysql.jdbc.*
// or you will have problems!

public class LoadDriver {
    public static void main(String[] args) {
        try {
            // The newInstance() call is a work around for some
            // broken Java implementations

        } catch (Exception ex) {
            // handle the error

After the driver has been registered with the DriverManager, you can obtain a Connection instance that is connected to a particular database by calling DriverManager.getConnection():

Example 1. Obtaining a Connection From the DriverManager

This example shows how you can obtain a Connection instance from the DriverManager. There are a few different signatures for the getConnection() method. You should see the API documentation that comes with your JDK for more specific information on how to use them.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

    ... try {
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/test?user=monty&password=greatsqldb");

            // Do something with the Connection

        } catch (SQLException ex) {
            // handle any errors
            System.out.println("SQLException: " + ex.getMessage());
            System.out.println("SQLState: " + ex.getSQLState());
            System.out.println("VendorError: " + ex.getErrorCode());

Once a Connection is established, it can be used to create Statements and PreparedStatements, as well as retrieve metadata about the database. This is explained in the following sections.

1.1.2. Using Statements to Execute SQL

Statements allow you to execute basic SQL queries and retrieve the results through the ResultSet class which is described later.

To create a Statement instance, you call the createStatement() method on the Connection object you have retrieved via one of the DriverManager.getConnection() or DataSource.getConnection() methods described earlier.

Once you have a Statement instance, you can execute a SELECT query by calling the executeQuery(String) method with the SQL you want to use.

To update data in the database use the executeUpdate(String SQL) method. This method returns the number of rows affected by the update statement.

If you don't know ahead of time whether the SQL statement will be a SELECT or an UPDATE/INSERT, then you can use the execute(String SQL) method. This method will return true if the SQL query was a SELECT, or false if an UPDATE/INSERT/DELETE query. If the query was a SELECT query, you can retrieve the results by calling the getResultSet() method. If the query was an UPDATE/INSERT/DELETE query, you can retrieve the affected rows count by calling getUpdateCount() on the Statement instance.

Example 2. Using java.sql.Statement to Execute a SELECT Query

// assume conn is an already created JDBC connection
Statement stmt = null;
ResultSet rs = null;

try {
    stmt = conn.createStatement();
    rs = stmt.executeQuery("SELECT foo FROM bar");

    // or alternatively, if you don't know ahead of time that
    // the query will be a SELECT...

    if (stmt.execute("SELECT foo FROM bar")) {
        rs = stmt.getResultSet();

    // Now do something with the ResultSet ....
} finally {
    // it is a good idea to release
    // resources in a finally{} block
    // in reverse-order of their creation
    // if they are no-longer needed

    if (rs != null) {
        try {
        } catch (SQLException sqlEx) { // ignore }

        rs = null;

    if (stmt != null) {
        try {
        } catch (SQLException sqlEx) { // ignore }

        stmt = null;

1.1.3. Using CallableStatements to Execute Stored Procedures

Starting with MySQL server version 5.0 when used with Connector/J 3.1.1 or newer, the java.sql.CallableStatement interface is fully implemented with the exception of the getParameterMetaData() method.

MySQL's stored procedure syntax is documented in the "Stored Procedures and Functions" section of the MySQL Reference Manual.

Connector/J exposes stored procedure functionality through JDBC's CallableStatement interface.

The following example shows a stored procedure that returns the value of inOutParam incremented by 1, and the string passed in via inputParam as a ResultSet :

Example 3. Stored Procedure Example

CREATE PROCEDURE demoSp(IN inputParam VARCHAR(255), INOUT inOutParam INT)
    SET z = inOutParam + 1;
    SET inOutParam = z;

    SELECT inputParam;

    SELECT CONCAT('zyxw', inputParam);

To use the demoSp procedure with Connector/J, follow these steps:

  1. Prepare the callable statement by using Connection.prepareCall() .

    Notice that you have to use JDBC escape syntax, and that the parentheses surrounding the parameter placeholders are not optional:

    Example 4. Using Connection.prepareCall()

    import java.sql.CallableStatement;
        // Prepare a call to the stored procedure 'demoSp'
        // with two parameters
        // Notice the use of JDBC-escape syntax ({call ...})
        CallableStatement cStmt = conn.prepareCall("{call demoSp(?, ?)}");
        cStmt.setString(1, "abcdefg");


    Connection.prepareCall() is an expensive method, due to the metadata retrieval that the driver performs to support output parameters. For performance reasons, you should try to minimize unnecessary calls to Connection.prepareCall() by reusing CallableStatement instances in your code.

  2. Register the output parameters (if any exist)

    To retrieve the values of output parameters (parameters specified as OUT or INOUT when you created the stored procedure), JDBC requires that they be specified before statement execution using the various registerOutputParameter() methods in the CallableStatement interface:

    Example 5. Registering Output Parameters

    import java.sql.Types;
        // Connector/J supports both named and indexed
        // output parameters. You can register output
        // parameters using either method, as well
        // as retrieve output parameters using either
        // method, regardless of what method was
        // used to register them.
        // The following examples show how to use
        // the various methods of registering
        // output parameters (you should of course
        // use only one registration per parameter).
        // Registers the second parameter as output
        // Registers the second parameter as output, and
        // uses the type 'INTEGER' for values returned from
        // getObject()
        cStmt.registerOutParameter(2, Types.INTEGER);
        // Registers the named parameter 'inOutParam'
        // Registers the named parameter 'inOutParam', and
        // uses the type 'INTEGER' for values returned from
        // getObject()
        cStmt.registerOutParameter("inOutParam", Types.INTEGER);

  3. Set the input parameters (if any exist)

    Input and in/out parameters are set as for PreparedStatement objects. However, CallableStatement also supports setting parameters by name:

    Example 6. Setting CallableStatement Input Parameters

        // Set a parameter by index
        cStmt.setString(1, "abcdefg");
        // Alternatively, set a parameter using
        // the parameter name
        cStmt.setString("inputParameter", "abcdefg");
        // Set the 'in/out' parameter using an index
        cStmt.setInt(2, 1);
        // Alternatively, set the 'in/out' parameter
        // by name
        cStmt.setInt("inOutParam", 1);

  4. Execute the CallableStatement , and retrieve any result sets or output parameters.

    While CallableStatement supports calling any of the Statement execute methods ( executeUpdate(), executeQuery() or execute() ), the most flexible method to call is execute(), as you do not need to know ahead of time if the stored procedure returns result sets:

    Example 7. Retrieving Results and Output Parameter Values

        boolean hadResults = cStmt.execute();
        // Process all returned result sets
        while (hadResults) {
            ResultSet rs = cStmt.getResultSet();
            // process result set
            hadResults = cStmt.getMoreResults();
        // Retrieve output parameters
        // Connector/J supports both index-based and
        // name-based retrieval
        int outputValue = cStmt.getInt(1); // index-based
        outputValue = cStmt.getInt("inOutParam"); // name-based

1.1.4. Retrieving AUTO_INCREMENT Column Values

Before version 3.0 of the JDBC API, there was no standard way of retrieving key values from databases that supported 'auto increment' or identity columns. With older JDBC drivers for MySQL, you could always use a MySQL- specific method on the Statement interface, or issue the query 'SELECT LAST_INSERT_ID()' after issuing an 'INSERT' to a table that had an AUTO_INCREMENT key. Using the MySQL-specific method call isn't portable, and issuing a 'SELECT' to get the AUTO_INCREMENT key's value requires another round- trip to the database, which isn't as efficient as possible. The following code snippets demonstrate the three different ways to retrieve AUTO_INCREMENT values. First, we demonstrate the use of the new JDBC-3.0 method 'getGeneratedKeys()' which is now the preferred method to use if you need to retrieve AUTO_INCREMENT keys and have access to JDBC-3.0. The second example shows how you can retrieve the same value using a standard 'SELECT LAST_INSERT_ID()' query. The final example shows how updatable result sets can retrieve the AUTO_INCREMENT value when using the method 'insertRow()'.

Example 8. Retrieving AUTO_INCREMENT Column Values using Statement.getGeneratedKeys()

   Statement stmt = null;
   ResultSet rs = null;

   try {

    // Create a Statement instance that we can use for
    // 'normal' result sets assuming you have a
    // Connection 'conn' to a MySQL database already
    // available

    stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,

    // Issue the DDL queries for the table for this example

    stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial");
            "CREATE TABLE autoIncTutorial ("
            + "priKey INT NOT NULL AUTO_INCREMENT, "
            + "dataField VARCHAR(64), PRIMARY KEY (priKey))");

    // Insert one row that will generate an AUTO INCREMENT
    // key in the 'priKey' field

            "INSERT INTO autoIncTutorial (dataField) "
            + "values ('Can I Get the Auto Increment Field?')",

    // Example of using Statement.getGeneratedKeys()
    // to retrieve the value of an auto-increment
    // value

    int autoIncKeyFromApi = -1;

    rs = stmt.getGeneratedKeys();

    if (rs.next()) {
        autoIncKeyFromApi = rs.getInt(1);
    } else {

        // throw an exception from here


    rs = null;

    System.out.println("Key returned from getGeneratedKeys():"
        + autoIncKeyFromApi);
} finally {

    if (rs != null) {
        try {
        } catch (SQLException ex) {
            // ignore

    if (stmt != null) {
        try {
        } catch (SQLException ex) {
            // ignore

Example 9. Retrieving AUTO_INCREMENT Column Values using 'SELECT LAST_INSERT_ID()'

   Statement stmt = null;
   ResultSet rs = null;

   try {

    // Create a Statement instance that we can use for
    // 'normal' result sets.

    stmt = conn.createStatement();

    // Issue the DDL queries for the table for this example

    stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial");
            "CREATE TABLE autoIncTutorial ("
            + "priKey INT NOT NULL AUTO_INCREMENT, "
            + "dataField VARCHAR(64), PRIMARY KEY (priKey))");

    // Insert one row that will generate an AUTO INCREMENT
    // key in the 'priKey' field

            "INSERT INTO autoIncTutorial (dataField) "
            + "values ('Can I Get the Auto Increment Field?')");

    // Use the MySQL LAST_INSERT_ID()
    // function to do the same thing as getGeneratedKeys()

    int autoIncKeyFromFunc = -1;
    rs = stmt.executeQuery("SELECT LAST_INSERT_ID()");

    if (rs.next()) {
        autoIncKeyFromFunc = rs.getInt(1);
    } else {
        // throw an exception from here


    System.out.println("Key returned from " + "'SELECT LAST_INSERT_ID()': "
        + autoIncKeyFromFunc);

} finally {

    if (rs != null) {
        try {
        } catch (SQLException ex) {
            // ignore

    if (stmt != null) {
        try {
        } catch (SQLException ex) {
            // ignore

Example 10. Retrieving AUTO_INCREMENT Column Values in Updatable ResultSets

   Statement stmt = null;
   ResultSet rs = null;

   try {

    // Create a Statement instance that we can use for
    // 'normal' result sets as well as an 'updatable'
    // one, assuming you have a Connection 'conn' to
    // a MySQL database already available

    stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,

    // Issue the DDL queries for the table for this example

    stmt.executeUpdate("DROP TABLE IF EXISTS autoIncTutorial");
            "CREATE TABLE autoIncTutorial ("
            + "priKey INT NOT NULL AUTO_INCREMENT, "
            + "dataField VARCHAR(64), PRIMARY KEY (priKey))");

    // Example of retrieving an AUTO INCREMENT key
    // from an updatable result set

    rs = stmt.executeQuery("SELECT priKey, dataField "
       + "FROM autoIncTutorial");


    rs.updateString("dataField", "AUTO INCREMENT here?");

    // the driver adds rows at the end


    // We should now be on the row we just inserted

    int autoIncKeyFromRS = rs.getInt("priKey");


    rs = null;

    System.out.println("Key returned for inserted row: "
        + autoIncKeyFromRS);

} finally {

    if (rs != null) {
        try {
        } catch (SQLException ex) {
            // ignore

    if (stmt != null) {
        try {
        } catch (SQLException ex) {
            // ignore


When you run the example code above, you should get the following output: Key returned from getGeneratedKeys(): 1 Key returned from 'SELECT LAST_INSERT_ID()': 1 Key returned for inserted row: 2 You should be aware, that at times, it can be tricky to use the 'SELECT LAST_INSERT_ID()' query, as that function's value is scoped to a connection. So, if some other query happens on the same connection, the value will be overwritten. On the other hand, the 'getGeneratedKeys()' method is scoped by the Statement instance, so it can be used even if other queries happen on the same connection, but not on the same Statement instance.

1.2. Installing Connector/J

Use the following instructions to install Connector/J

1.2.1. Required Software Versions Java Versions Supported

MySQL Connector/J supports Java-2 JVMs, including JDK-1.2.x, JDK-1.3.x, JDK-1.4.x and JDK-1.5.x, and requires JDK-1.4.x or newer to compile (but not run). MySQL Connector/J does not support JDK-1.1.x or JDK-1.0.x

Because of the implementation of java.sql.Savepoint, Connector/J 3.1.0 and newer will not run on JDKs older than 1.4 unless the class verifier is turned off (-Xverify:none), as the class verifier will try to load the class definition for java.sql.Savepoint even though it is not accessed by the driver unless you actually use savepoint functionality.

Caching functionality provided by Connector/J 3.1.0 or newer is also not available on JVMs older than 1.4.x, as it relies on java.util.LinkedHashMap which was first available in JDK-1.4.0. MySQL Server Version Guidelines

MySQL Connector/J supports all known MySQL server versions. Some features (foreign keys, updatable result sets) require more recent versions of MySQL to operate.

When connecting to MySQL server version 4.1 or newer, it is best to use MySQL Connector/J version 3.1, as it has full support for features in the newer versions of the server, including Unicode characters, views, stored procedures and server-side prepared statements.

While Connector/J version 3.0 will connect to MySQL server, version 4.1 or newer, and implements Unicode characters and the new authorization mechanism, Connector/J 3.0 will not be updated to support new features in current and future server versions. Installing the Driver and Configuring the CLASSPATH

MySQL Connector/J is distributed as a .zip or .tar.gz archive containing the sources, the class files a class-file only "binary" .jar archive named "mysql-connector-java-[version]-bin.jar", and starting with Connector/J 3.1.8 a "debug" build of the driver in a file named "mysql-connector-java-[version]-bin-g.jar".

Starting with Connector/J 3.1.9, we don't ship the .class files "unbundled", they are only available in the JAR archives that ship with the driver.

You should not use the "debug" build of the driver unless instructed do do so when reporting a problem or bug to MySQL AB, as it is not designed to be run in production environments, and will have adverse performance impact when used. The debug binary also depends on the Aspect/J runtime library, which is located in the src/lib/aspectjrt.jar file that comes with the Connector/J distribution.

You will need to use the appropriate gui or command-line utility to un-archive the distribution (for example, WinZip for the .zip archive, and "tar" for the .tar.gz archive). Because there are potentially long filenames in the distribution, we use the GNU tar archive format. You will need to use GNU tar (or an application that understands the GNU tar archive format) to unpack the .tar.gz variant of the distribution.

Once you have extracted the distribution archive, you can install the driver by placing mysql-connector-java-[version]-bin.jar in your classpath, either by adding the FULL path to it to your CLASSPATH enviornment variable, or by directly specifying it with the commandline switch -cp when starting your JVM

If you are going to use the driver with the JDBC DriverManager, you would use "com.mysql.jdbc.Driver" as the class that implements java.sql.Driver.

Example 11. Setting the CLASSPATH Under UNIX

The following command works for 'csh' under UNIX:

$ setenv CLASSPATH /path/to/mysql-connector-java-[version]-bin.jar:$CLASSPATH

The above command can be added to the appropriate startup file for the login shell to make MySQL Connector/J available to all Java applications.

If you want to use MySQL Connector/J with an application server such as Tomcat or JBoss, you will have to read your vendor's documentation for more information on how to configure third-party class libraries, as most application servers ignore the CLASSPATH environment variable. This document does contain configuration examples for some J2EE application servers in the section named "Using Connector/J with J2EE and Other Java Frameworks", however the authoritative source for JDBC connection pool configuration information for your particular application server is the documentation for that application server.

If you are developing servlets and/or JSPs, and your application server is J2EE-compliant, you can put the driver's .jar file in the WEB-INF/lib subdirectory of your webapp, as this is a standard location for third party class libraries in J2EE web applications.

You can also use the MysqlDataSource or MysqlConnectionPoolDataSource classes in the com.mysql.jdbc.jdbc2.optional package, if your J2EE application server supports or requires them. The various MysqlDataSource classes support the following parameters (through standard "set" mutators):

  • user

  • password

  • serverName (see the previous section about fail-over hosts)

  • databaseName

  • port

1.2.2. Upgrading from an Older Version

MySQL AB tries to keep the upgrade process as easy as possible, however as is the case with any software, sometimes changes need to be made in new versions to support new features, improve existing functionality, or comply with new standards.

This section has information about what users who are upgrading from one version of Connector/J to another (or to a new version of the MySQL server, with respect to JDBC functionality) should be aware of. Upgrading from MySQL Connector/J 3.0 to 3.1

Connector/J 3.1 is designed to be backwards-compatible with Connector/J 3.0 as much as possible. Major changes are isolated to new functionality exposed in MySQL-4.1 and newer, which includes Unicode character sets, server-side prepared statements, SQLState codes returned in error messages by the server and various performance enhancements that can be enabled or disabled via configuration properties.

  • Unicode Character Sets - See the next section, as well as the "Character Sets" section in the server manual for information on this new feature of MySQL. If you have something misconfigured, it will usually show up as an error with a message similar to 'Illegal mix of collations'.

  • Server-side Prepared Statements - Connector/J 3.1 will automatically detect and use server-side prepared statements when they are available (MySQL server version 4.1.0 and newer).

    Starting with version 3.1.7, the driver scans SQL you are preparing via all variants of Connection.prepareStatement() to determine if it is a supported type of statement to prepare on the server side, and if it is not supported by the server, it instead prepares it as a client-side emulated prepared statement. You can disable this feature by passing 'emulateUnsupportedPstmts=false' in your JDBC URL.

    If your application encounters issues with server-side prepared statements, you can revert to the older client-side emulated prepared statement code that is still presently used for MySQL servers older than 4.1.0 with the following connection property:


  • Datetimes with all-zero components ('0000-00-00 ...') - These values can not be represented reliably in Java. Connector/J 3.0.x always converted them to NULL when being read from a ResultSet.

    Connector/J 3.1 throws an exception by default when these values are encountered as this is the most correct behavior according to the JDBC and SQL standards. This behavior can be modified using the ' zeroDateTimeBehavior ' configuration property. The allowable values are: 'exception' (the default), which throws a SQLException with a SQLState of 'S1009', 'convertToNull', which returns NULL instead of the date, and 'round', which rounds the date to the nearest closest value which is '0001-01-01'.

    Starting with Connector/J 3.1.7, ResultSet.getString() can be decoupled from this behavior via ' noDatetimeStringSync=true ' (the default value is 'false') so that you can get retrieve the unaltered all-zero value as a String. It should be noted that this also precludes using any timezone conversions, therefore the driver will not allow you to enable noDatetimeStringSync and useTimezone at the same time.

  • New SQLState Codes - Connector/J 3.1 uses SQL:1999 SQLState codes returned by the MySQL server (if supported), which are different than the "legacy" X/Open state codes that Connector/J 3.0 uses. If connected to a MySQL server older than MySQL-4.1.0 (the oldest version to return SQLStates as part of the error code), the driver will use a built-in mapping. You can revert to the old mapping by using the following configuration property:


  • Calling ResultSet.getString() on a BLOB column will now return the address of the byte[] array that represents it, instead of a String representation of the BLOB. BLOBs have no character set, so they can't be converted to java.lang.Strings without data loss or corruption.

    To store strings in MySQL with LOB behavior, use one of the TEXT types, which the driver will treat as a java.sql.Clob.

  • Starting with Connector/J 3.1.8 a "debug" build of the driver in a file named "mysql-connector-java-[version]-bin-g.jar" is shipped alongside the normal "binary" jar file that is named "mysql-connector-java-[version]-bin.jar".

    Starting with Connector/J 3.1.9, we don't ship the .class files "unbundled", they are only available in the JAR archives that ship with the driver.

    You should not use the "debug" build of the driver unless instructed do do so when reporting a problem or bug to MySQL AB, as it is not designed to be run in production environments, and will have adverse performance impact when used. The debug binary also depends on the Aspect/J runtime library, which is located in the src/lib/aspectjrt.jar file that comes with the Connector/J distribution. JDBC-Specific Issues When Upgrading to MySQL Server Version 4.1 or Newer
  • Using the UTF-8 Character Encoding - Prior to MySQL server version 4.1, the UTF-8 character encoding was not supported by the server, however the JDBC driver could use it, allowing storage of multiple character sets in latin1 tables on the server.

    Starting with MySQL-4.1, this functionality is deprecated. If you have applications that rely on this functionality, and can not upgrade them to use the official Unicode character support in MySQL server version 4.1 or newer, you should add the following property to your connection URL:


  • Server-side Prepared Statements - Connector/J 3.1 will automatically detect and use server-side prepared statements when they are available (MySQL server version 4.1.0 and newer). If your application encounters issues with server-side prepared statements, you can revert to the older client-side emulated prepared statement code that is still presently used for MySQL servers older than 4.1.0 with the following connection property:


1.3. JDBC Reference

1.3.1. Driver/Datasource Class Names, URL Syntax and Configuration Properties for Connector/J

The name of the class that implements java.sql.Driver in MySQL Connector/J is 'com.mysql.jdbc.Driver'. The 'org.gjt.mm.mysql.Driver' class name is also usable to remain backwards-compatible with MM.MySQL. You should use this class name when registering the driver, or when otherwise configuring software to use MySQL Connector/J.

The JDBC URL format for MySQL Connector/J is as follows, with items in square brackets ([, ]) being optional:


If the hostname is not specified, it defaults to ''. If the port is not specified, it defaults to '3306', the default port number for MySQL servers.


If the database is not specified, the connection will be made with no 'current' database. In this case, you will need to either call the 'setCatalog()' method on the Connection instance or fully-specify table names using the database name (i.e. 'SELECT dbname.tablename.colname FROM dbname.tablename...') in your SQL. Not specifying the database to use upon connection is generally only useful when building tools that work with multiple databases, such as GUI database managers.

MySQL Connector/J has fail-over support. This allows the driver to fail-over to any number of "slave" hosts and still perform read-only queries. Fail-over only happens when the connection is in an autoCommit(true) state, because fail-over can not happen reliably when a transaction is in progress. Most application servers and connection pools set autoCommit to 'true' at the end of every transaction/connection use.

The fail-over functionality has the following behavior:

If the URL property "autoReconnect" is false: Failover only happens at connection initialization, and failback occurs when the driver determines that the first host has become available again.

If the URL property "autoReconnect" is true: Failover happens when the driver determines that the connection has failed (before every query), and falls back to the first host when it determines that the host has become available again (after queriesBeforeRetryMaster queries have been issued).

In either case, whenever you are connected to a "failed-over" server, the connection will be set to read-only state, so queries that would modify data will have exceptions thrown (the query will never be processed by the MySQL server).

Configuration properties define how Connector/J will make a connection to a MySQL server. Unless otherwise noted, properties can be set for a DataSource object or for a Connection object.

Configuration Properties can be set in one of the following ways:

  • Using the set*() methods on MySQL implementations of java.sql.DataSource (which is the preferred method when using implementations of java.sql.DataSource):

    • com.mysql.jdbc.jdbc2.optional.MysqlDataSource

    • com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource

  • As a key/value pair in the java.util.Properties instance passed to DriverManager.getConnection() or Driver.connect()

  • As a JDBC URL parameter in the URL given to java.sql.DriverManager.getConnection(), java.sql.Driver.connect() or the MySQL implementations of javax.sql.DataSource's setURL() method.


    If the mechanism you use to configure a JDBC URL is XML-based, you will need to use the XML character literal & to separate configuration parameters, as the ampersand is a reserved character for XML.

The properties are listed in the following table:

Table 1. Connection Properties

Property NameDefinitionRequired?Default ValueSince Version
userThe user to connect asNo all
passwordThe password to use when connectingNo all
socketFactoryThe name of the class that the driver should use for creating socket connections to the server. This class must implement the interface 'com.mysql.jdbc.SocketFactory' and have public no-args constructor.Nocom.mysql.jdbc.StandardSocketFactory3.0.3
connectTimeoutTimeout for socket connect (in milliseconds), with 0 being no timeout. Only works on JDK-1.4 or newer. Defaults to '0'.No03.0.1
socketTimeoutTimeout on network socket operations (0, the default means no timeout).No03.0.1
useConfigsLoad the comma-delimited list of configuration properties before parsing the URL or applying user-specified properties. These configurations are explained in the 'Configurations' of the documentation.No 3.1.5
interactiveClientSet the CLIENT_INTERACTIVE flag, which tells MySQL to timeout connections based on INTERACTIVE_TIMEOUT instead of WAIT_TIMEOUTNofalse3.1.0
propertiesTransformAn implementation of com.mysql.jdbc.ConnectionPropertiesTransform that the driver will use to modify URL properties passed to the driver before attempting a connectionNo 3.1.4
useCompressionUse zlib compression when communicating with the server (true/false)? Defaults to 'false'.Nofalse3.0.17
High Availability and Clustering
autoReconnectShould the driver try to re-establish stale and/or dead connections? If enabled the driver will throw an exception for a queries issued on a stale or dead connection, which belong to the current transaction, but will attempt reconnect before the next query issued on the connection in a new transaction. The use of this feature is not recommended, because it has side effects related to session state and data consistency when applications don'thandle SQLExceptions properly, and is only designed to be used when you are unable to configure your application to handle SQLExceptions resulting from dead and/or stale connections properly. Alternatively, investigate setting the MySQL server variable "wait_timeout"to some high value rather than the default of 8 hours.Nofalse1.1
autoReconnectForPoolsUse a reconnection strategy appropriate for connection pools (defaults to 'false')Nofalse3.1.3
failOverReadOnlyWhen failing over in autoReconnect mode, should the connection be set to 'read-only'?Notrue3.0.12
reconnectAtTxEndIf autoReconnect is set to true, should the driver attempt reconnectionsat the end of every transaction?Nofalse3.0.10
roundRobinLoadBalanceWhen autoReconnect is enabled, and failoverReadonly is false, should we pick hosts to connect to on a round-robin basis?Nofalse3.1.2
queriesBeforeRetryMasterNumber of queries to issue before falling back to master when failed over (when using multi-host failover). Whichever condition is met first, 'queriesBeforeRetryMaster' or 'secondsBeforeRetryMaster' will cause an attempt to be made to reconnect to the master. Defaults to 50.No503.0.2
secondsBeforeRetryMasterHow long should the driver wait, when failed over, before attempting to reconnect to the master server? Whichever condition is met first, 'queriesBeforeRetryMaster' or 'secondsBeforeRetryMaster' will cause an attempt to be made to reconnect to the master. Time in seconds, defaults to 30No303.0.2
enableDeprecatedAutoreconnectAuto-reconnect functionality is deprecated starting with version 3.2, and will be removed in version 3.3. Set this property to 'true' to disable the check for the feature being configured.Nofalse3.2.1
allowMultiQueriesAllow the use of ';' to delimit multiple queries during one statement (true/false, defaults to 'false'Nofalse3.1.1
useSSLUse SSL when communicating with the server (true/false), defaults to 'false'Nofalse3.0.2
requireSSLRequire SSL connection if useSSL=true? (defaults to 'false').Nofalse3.1.0
allowUrlInLocalInfileShould the driver allow URLs in 'LOAD DATA LOCAL INFILE' statements?Nofalse3.1.4
paranoidTake measures to prevent exposure sensitive information in error messages and clear data structures holding sensitive data when possible? (defaults to 'false')Nofalse3.0.1
Performance Extensions
metadataCacheSizeThe number of queries to cacheResultSetMetadata for if cacheResultSetMetaData is set to 'true' (default 50)No503.1.1
prepStmtCacheSizeIf prepared statement caching is enabled, how many prepared statements should be cached?No253.0.10
prepStmtCacheSqlLimitIf prepared statement caching is enabled, what's the largest SQL the driver will cache the parsing for?No2563.0.10
maintainTimeStatsShould the driver maintain various internal timers to enable idle time calculations as well as more verbose error messages when the connection to the server fails? Setting this property to false removes at least two calls to System.getCurrentTimeMillis() per query.Notrue3.1.9
blobSendChunkSizeChunk to use when sending BLOB/CLOBs via ServerPreparedStatementsNo10485763.1.9
cacheCallableStmtsShould the driver cache the parsing stage of CallableStatementsNofalse3.1.2
cachePrepStmtsShould the driver cache the parsing stage of PreparedStatements of client-side prepared statements, the "check" for suitability of server-side prepared and server-side prepared statements themselves?Nofalse3.0.10
cacheResultSetMetadataShould the driver cache ResultSetMetaData for Statements and PreparedStatements? (Req. JDK-1.4+, true/false, default 'false')Nofalse3.1.1
cacheServerConfigurationShould the driver cache the results of 'SHOW VARIABLES' and 'SHOW COLLATION' on a per-URL basis?Nofalse3.1.5
dontTrackOpenResourcesThe JDBC specification requires the driver to automatically track and close resources, however if your application doesn't do a good job of explicitly calling close() on statements or result sets, this can cause memory leakage. Setting this property to true relaxes this constraint, and can be more memory efficient for some applications.Nofalse3.1.7
dynamicCalendarsShould the driver retrieve the default calendar when required, or cache it per connection/session?Nofalse3.1.5
elideSetAutoCommitsIf using MySQL-4.1 or newer, should the driver only issue 'set autocommit=n' queries when the server's state doesn't match the requested state by Connection.setAutoCommit(boolean)?Nofalse3.1.3
holdResultsOpenOverStatementCloseShould the driver close result sets on Statement.close() as required by the JDBC specification?Nofalse3.1.7
locatorFetchBufferSizeIf 'emulateLocators' is configured to 'true', what size buffer should be used when fetching BLOB data for getBinaryInputStream?No10485763.2.1
useFastIntParsingUse internal String->Integer conversion routines to avoid excessive object creation?Notrue3.1.4
useLocalSessionStateShould the driver refer to the internal values of autocommit and transaction isolation that are set by Connection.setAutoCommit() and Connection.setTransactionIsolation(), rather than querying the database?Nofalse3.1.7
useNewIOShould the driver use the java.nio.* interfaces for network communication (true/false), defaults to 'false'Nofalse3.1.0
useReadAheadInputUse newer, optimized non-blocking, buffered input stream when reading from the server?Notrue3.1.5
loggerThe name of a class that implements 'com.mysql.jdbc.log.Log' that will be used to log messages to.(default is 'com.mysql.jdbc.log.StandardLogger', which logs to STDERR)Nocom.mysql.jdbc.log.StandardLogger3.1.1
profileSQLTrace queries and their execution/fetch times to the configured logger (true/false) defaults to 'false'Nofalse3.1.0
reportMetricsIntervalMillisIf 'gatherPerfMetrics' is enabled, how often should they be logged (in ms)?No300003.1.2
maxQuerySizeToLogControls the maximum length/size of a query that will get logged when profiling or tracingNo20483.1.3
packetDebugBufferSizeThe maximum number of packets to retain when 'enablePacketDebug' is trueNo203.1.3
slowQueryThresholdMillisIf 'logSlowQueries' is enabled, how long should a query (in ms) before it is logged as 'slow'?No20003.1.2
useUsageAdvisorShould the driver issue 'usage' warnings advising proper and efficient usage of JDBC and MySQL Connector/J to the log (true/false, defaults to 'false')?Nofalse3.1.1
autoGenerateTestcaseScriptShould the driver dump the SQL it is executing, including server-side prepared statements to STDERR?Nofalse3.1.9
dumpQueriesOnExceptionShould the driver dump the contents of the query sent to the server in the message for SQLExceptions?Nofalse3.1.3
enablePacketDebugWhen enabled, a ring-buffer of 'packetDebugBufferSize' packets will be kept, and dumped when exceptions are thrown in key areas in the driver's codeNofalse3.1.3
explainSlowQueriesIf 'logSlowQueries' is enabled, should the driver automatically issue an 'EXPLAIN' on the server and send the results to the configured log at a WARN level?Nofalse3.1.2
logSlowQueriesShould queries that take longer than 'slowQueryThresholdMillis' be logged?Nofalse3.1.2
traceProtocolShould trace-level network protocol be logged?Nofalse3.1.2
useUnicodeShould the driver use Unicode character encodings when handling strings? Should only be used when the driver can't determine the character set mapping, or you are trying to 'force' the driver to use a character set that MySQL either doesn't natively support (such as UTF-8), true/false, defaults to 'true'Nofalse1.1g
characterEncodingIf 'useUnicode' is set to true, what character encoding should the driver use when dealing with strings? (defaults is to 'autodetect')No 1.1g
characterSetResultsCharacter set to tell the server to return results as.No 3.0.13
connectionCollationIf set, tells the server to use this collation via 'set collation_connection'No 3.0.13
sessionVariablesA comma-separated list of name/value pairs to be sent as SET SESSION ... to the server when the driver connects.No 3.1.8
allowNanAndInfShould the driver allow NaN or +/- INF values in PreparedStatement.setDouble()?Nofalse3.1.5
autoDeserializeShould the driver automatically detect and de-serialize objects stored in BLOB fields?Nofalse3.1.5
capitalizeTypeNamesCapitalize type names in DatabaseMetaData? (usually only useful when using WebObjects, true/false, defaults to 'false')Nofalse2.0.7
clobberStreamingResultsThis will cause a 'streaming' ResultSet to be automatically closed, and any outstanding data still streaming from the server to be discarded if another query is executed before all the data has been read from the server.Nofalse3.0.9
continueBatchOnErrorShould the driver continue processing batch commands if one statement fails. The JDBC spec allows either way (defaults to 'true').Notrue3.0.3
createDatabaseIfNotExistCreates the database given in the URL if it doesn't yet exist. Assumes the configured user has permissions to create databases.Nofalse3.1.9
emptyStringsConvertToZeroShould the driver allow conversions from empty string fields to numeric values of '0'?Notrue3.1.8
emulateUnsupportedPstmtsShould the driver detect prepared statements that are not supported by the server, and replace them with client-side emulated versions?Notrue3.1.7
ignoreNonTxTablesIgnore non-transactional table warning for rollback? (defaults to 'false').Nofalse3.0.9
jdbcCompliantTruncationShould the driver throw java.sql.DataTruncation exceptions when data is truncated as is required by the JDBC specification when connected to a server that supports warnings(MySQL 4.1.0 and newer)?Notrue3.1.2
maxRowsThe maximum number of rows to return (0, the default means return all rows).No-1all versions
noDatetimeStringSyncDon't ensure that ResultSet.getDatetimeType().toString().equals(ResultSet.getString())Nofalse3.1.7
nullCatalogMeansCurrentWhen DatabaseMetadataMethods ask for a 'catalog' parameter, does the value null mean use the current catalog? (this is not JDBC-compliant, but follows legacy behavior from earlier versions of the driver)Notrue3.1.8
nullNamePatternMatchesAllShould DatabaseMetaData methods that accept *pattern parameters treat null the same as '%' (this is not JDBC-compliant, however older versions of the driver accepted this departure from the specification)Notrue3.1.8
pedanticFollow the JDBC spec to the letter.Nofalse3.0.0
relaxAutoCommitIf the version of MySQL the driver connects to does not support transactions, still allow calls to commit(), rollback() and setAutoCommit() (true/false, defaults to 'false')?Nofalse2.0.13
retainStatementAfterResultSetCloseShould the driver retain the Statement reference in a ResultSet after ResultSet.close() has been called. This is not JDBC-compliant after JDBC-4.0.Nofalse3.1.11
rollbackOnPooledCloseShould the driver issue a rollback() when the logical connection in a pool is closed?Notrue3.0.15
runningCTS13Enables workarounds for bugs in Sun's JDBC compliance testsuite version 1.3Nofalse3.1.7
serverTimezoneOverride detection/mapping of timezone. Used when timezone from server doesn't map to Java timezoneNo 3.0.2
strictFloatingPointUsed only in older versions of compliance testNofalse3.0.0
strictUpdatesShould the driver do strict checking (all primary keys selected) of updatable result sets (true, false, defaults to 'true')?Notrue3.0.4
tinyInt1isBitShould the driver treat the datatype TINYINT(1) as the BIT type (because the server silently converts BIT -> TINYINT(1) when creating tables)?Notrue3.0.16
transformedBitIsBooleanIf the driver converts TINYINT(1) to a different type, should it use BOOLEAN instead of BIT for future compatibility with MySQL-5.0, as MySQL-5.0 has a BIT type?Nofalse3.1.9
ultraDevHackCreate PreparedStatements for prepareCall() when required, because UltraDev is broken and issues a prepareCall() for _all_ statements? (true/false, defaults to 'false')Nofalse2.0.3
useHostsInPrivilegesAdd '@hostname' to users in DatabaseMetaData.getColumn/TablePrivileges() (true/false), defaults to 'true'.Notrue3.0.2
useOldUTF8BehaviorUse the UTF-8 behavior the driver did when communicating with 4.0 and older serversNofalse3.1.6
useOnlyServerErrorMessagesDon't prepend 'standard' SQLState error messages to error messages returned by the server.Notrue3.0.15
useServerPrepStmtsUse server-side prepared statements if the server supports them? (defaults to 'true').Notrue3.1.0
useSqlStateCodesUse SQL Standard state codes instead of 'legacy' X/Open/SQL state codes (true/false), default is 'true'Notrue3.1.3
useStreamLengthsInPrepStmtsHonor stream length parameter in PreparedStatement/ResultSet.setXXXStream() method calls (true/false, defaults to 'true')?Notrue3.0.2
useTimezoneConvert time/date types between client and server timezones (true/false, defaults to 'false')?Nofalse3.0.2
useUnbufferedInputDon't use BufferedInputStream for reading data from the serverNotrue3.0.11
yearIsDateTypeShould the JDBC driver treat the MySQL type "YEAR" as a java.sql.Date, or as a SHORT?Notrue3.1.9
zeroDateTimeBehaviorWhat should happen when the driver encounters DATETIME values that are composed entirely of zeroes (used by MySQL to represent invalid dates)? Valid values are 'exception', 'round' and 'convertToNull'.Noexception3.1.4

Connector/J also supports access to MySQL via named pipes on Windows NT/2000/XP using the 'NamedPipeSocketFactory' as a plugin-socket factory via the 'socketFactory' property. If you don't use a 'namedPipePath' property, the default of '\\.\pipe\MySQL' will be used. If you use the NamedPipeSocketFactory, the hostname and port number values in the JDBC url will be ignored.

Adding the following property to your URL will enable the NamedPipeSocketFactory:


Named pipes only work when connecting to a MySQL server on the same physical machine as the one the JDBC driver is being used on. In simple performance tests, it appears that named pipe access is between 30%-50% faster than the standard TCP/IP access.

You can create your own socket factories by following the example code in com.mysql.jdbc.NamedPipeSocketFactory , or com.mysql.jdbc.StandardSocketFactory .

1.3.2. JDBC API Implementation Notes

MySQL Connector/J passes all of the tests in the publicly-available version of Sun's JDBC compliance testsuite. However, in many places the JDBC specification is vague about how certain functionality should be implemented, or the specification allows leeway in implementation.

This section gives details on a interface-by-interface level about how certain implementation decisions may affect how you use MySQL Connector/J.

  • Blob

    The Blob implementation does not allow in-place modification (they are 'copies', as reported by the DatabaseMetaData.locatorsUpdateCopies() method). Because of this, you should use the corresponding PreparedStatement.setBlob() or ResultSet.updateBlob() (in the case of updatable result sets) methods to save changes back to the database.

    Starting with Connector/J version 3.1.0, you can emulate Blobs with locators by adding the property 'emulateLocators=true' to your JDBC URL. You must then use a column alias with the value of the column set to the actual name of the Blob column in the SELECT that you write to retrieve the Blob. The SELECT must also reference only one table, the table must have a primary key, and the SELECT must cover all columns that make up the primary key. The driver will then delay loading the actual Blob data until you retrieve the Blob and call retrieval methods (getInputStream(), getBytes(), etc) on it.

  • CallableStatement

    Starting with Connector/J 3.1.1, stored procedures are supported when connecting to MySQL version 5.0 or newer via the CallableStatement interface. Currently, the getParameterMetaData() method of CallableStatement is not supported.

  • Clob

    The Clob implementation does not allow in-place modification (they are 'copies', as reported by the DatabaseMetaData.locatorsUpdateCopies() method). Because of this, you should use the PreparedStatement.setClob() method to save changes back to the database. The JDBC API does not have a ResultSet.updateClob() method.

  • Connection

    Unlike older versions of MM.MySQL the 'isClosed()' method does not "ping" the server to determine if it is alive. In accordance with the JDBC specification, it only returns true if 'closed()' has been called on the connection. If you need to determine if the connection is still valid, you should issue a simple query, such as "SELECT 1". The driver will throw an exception if the connection is no longer valid.

  • DatabaseMetaData

    Foreign Key information (getImported/ExportedKeys() and getCrossReference()) is only available from 'InnoDB'-type tables. However, the driver uses 'SHOW CREATE TABLE' to retrieve this information, so when other table types support foreign keys, the driver will transparently support them as well.

  • Driver

  • PreparedStatement

    PreparedStatements are implemented by the driver, as MySQL does not have a prepared statement feature. Because of this, the driver does not implement getParameterMetaData() or getMetaData() as it would require the driver to have a complete SQL parser in the client.

    Starting with version 3.1.0 MySQL Connector/J, server-side prepared statements and 'binary-encoded' result sets are used when the server supports them.

    Take care when using a server-side prepared statement with "large" parameters that are set via setBinaryStream(), setAsciiStream(), setUnicodeStream(), setBlob(), or setClob(). If you want to re-execute the statement with any "large" parameter changed to a non-"large" parameter, it is necessary to call clearParameters() and set all parameters again. The reason for this is as follows:

    • The driver streams the 'large' data 'out-of-band' to the prepared statement on the server side when the parameter is set (before execution of the prepared statement).

    • Once that has been done, the stream used to read the data on the client side is closed (as per the JDBC spec), and can't be read from again.

    • If a parameter changes from "large" to non-"large", the driver must reset the server-side state of the prepared statement to allow the parameter that is being changed to take the place of the prior "large" value. This removes all of the 'large' data that has already been sent to the server, thus requiring the data to be re-sent, via the setBinaryStream(), setAsciiStream(), setUnicodeStream(), setBlob() or setClob() methods.

    Consequently, if you want to change the "type" of a parameter to a non-"large" one, you must call clearParameters() and set all parameters of the prepared statement again before it can be re-executed.

  • ResultSet

    By default, ResultSets are completely retrieved and stored in memory. In most cases this is the most efficient way to operate, and due to the design of the MySQL network protocol is easier to implement. If you are working with ResultSets that have a large number of rows or large values, and can not allocate heap space in your JVM for the memory required, you can tell the driver to 'stream' the results back one row at-a-time.

    To enable this functionality, you need to create a Statement instance in the following manner:

    stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,

    The combination of a forward-only, read-only result set, with a fetch size of Integer.MIN_VALUE serves as a signal to the driver to "stream" result sets row-by-row. After this any result sets created with the statement will be retrieved row-by-row.

    There are some caveats with this approach. You will have to read all of the rows in the result set (or close it) before you can issue any other queries on the connection, or an exception will be thrown.

    The earliest the locks these statements hold can be released (whether they be MyISAM table-level locks or row-level locks in some other storage engine such as InnoDB) is when the statement completes.

    If the statement is within scope of a transaction, then locks are released when the transaction completes (which implies that the statement needs to complete first). As with most other databases, statements are not complete until all the results pending on the statement are read or the active result set for the statement is closed.

    Therefore, if using "streaming" results, you should process them as quickly as possible if you want to maintain concurrent access to the tables referenced by the statement producing the result set.

  • ResultSetMetaData

    The "isAutoIncrement()" method only works when using MySQL servers 4.0 and newer.

  • Statement

    When using versions of the JDBC driver earlier than 3.2.1, and connected to server versions earlier than 5.0.3, the "setFetchSize()" method has no effect, other than to toggle result set streaming as described above.

    MySQL does not support SQL cursors, and the JDBC driver doesn't emulate them, so "setCursorName()" has no effect.

1.3.3. Java, JDBC and MySQL Types

MySQL Connector/J is flexible in the way it handles conversions between MySQL data types and Java data types.

In general, any MySQL data type can be converted to a java.lang.String, and any numerical type can be converted to any of the Java numerical types, although round-off, overflow, or loss of precision may occur.

Starting with Connector/J 3.1.0, the JDBC driver will issue warnings or throw DataTruncation exceptions as is required by the JDBC specification unless the connection was configured not to do so by using the property "jdbcCompliantTruncation" and setting it to "false".

The conversions that are always guaranteed to work are listed in the following table:

Table 2. Conversion Table

These MySQL Data TypesCan always be converted to these Java types
CHAR, VARCHAR, BLOB, TEXT, ENUM, and SETjava.lang.String, java.io.InputStream, java.io.Reader, java.sql.Blob, java.sql.Clob
FLOAT, REAL, DOUBLE PRECISION, NUMERIC, DECIMAL, TINYINT, SMALLINT, MEDIUMINT, INTEGER, BIGINTjava.lang.String, java.lang.Short, java.lang.Integer, java.lang.Long, java.lang.Double, java.math.BigDecimal


round-off, overflow or loss of precision may occur if you choose a Java numeric data type that has less precision or capacity than the MySQL data type you are converting to/from.

DATE, TIME, DATETIME, TIMESTAMPjava.lang.String, java.sql.Date, java.sql.Timestamp

The ResultSet.getObject() method uses the following type conversions between MySQL and Java types, following the JDBC specification where appropriate:

Table 3. MySQL Types to Java Types for ResultSet.getObject()

MySQL Type NameReturned as Java Class
BIT(1) (new in MySQL-5.0)java.lang.Boolean
BIT( > 1) (new in MySQL-5.0)byte[]
TINYINTjava.lang.Boolean if the configuration property "tinyInt1isBit" is set to "true" (the default) and the storage size is "1", or java.lang.Integer if not.
BOOL , BOOLEANSee TINYINT , above as these are aliases for TINYINT(1) , currently.
SMALLINT[(M)] [UNSIGNED]java.lang.Integer (regardless if UNSIGNED or not)
MEDIUMINT[(M)] [UNSIGNED]java.lang.Integer (regardless if UNSIGNED or not)
INT,INTEGER[(M)] [UNSIGNED]java.lang.Integer , if UNSIGNED java.lang.Long
BIGINT[(M)] [UNSIGNED]java.lang.Long , if UNSIGNED java.math.BigInteger
YEAR[(2|4)]java.sql.Date (with the date set two January 1st, at midnight)
CHAR(M)java.lang.String (unless the character set for the column is BINARY , then byte[] is returned.
VARCHAR(M) [BINARY]java.lang.String (unless the character set for the column is BINARY , then byte[] is returned.

1.3.4. Using Character Sets and Unicode

All strings sent from the JDBC driver to the server are converted automatically from native Java Unicode form to the client character encoding, including all queries sent via Statement.execute(), Statement.executeUpdate(), Statement.executeQuery() as well as all PreparedStatement and CallableStatement parameters with the exclusion of parameters set using setBytes(), setBinaryStream(), setAsiiStream(), setUnicodeStream() and setBlob() .

Prior to MySQL Server 4.1, Connector/J supported a single character encoding per connection, which could either be automatically detected from the server configuration, or could be configured by the user through the useUnicode and characterEncoding properties.

Starting with MySQL Server 4.1, Connector/J supports a single character encoding between client and server, and any number of character encodings for data returned by the server to the client in ResultSets .

The character encoding between client and server is automatically detected upon connection. The encoding used by the driver is specified on the server via the configuration variable ' character_set ' for server versions older than 4.1.0 and ' character_set_server ' for server versions 4.1.0 and newer. See the "Server Character Set and Collation" section in the MySQL server manual for more information.

To override the automatically-detected encoding on the client side, use the characterEncoding property in the URL used to connect to the server.

When specifying character encodings on the client side, Java-style names should be used. The following table lists Java-style names for MySQL character sets:

Table 4. MySQL to Java Encoding Name Translations

MySQL Character Set NameJava-Style Character Encoding Name


Do not issue the query 'set names' with Connector/J, as the driver will not detect that the character set has changed, and will continue to use the character set detected during the initial connection setup.

To allow multiple character sets to be sent from the client, the "UTF-8" encoding should be used, either by configuring "utf8" as the default server character set, or by configuring the JDBC driver to use "UTF-8" through the characterEncoding property.

1.3.5. Connecting Securely Using SSL

SSL in MySQL Connector/J encrypts all data (other than the initial handshake) between the JDBC driver and the server. The performance penalty for enabling SSL is an increase in query processing time between 35% and 50%, depending on the size of the query, and the amount of data it returns.

For SSL Support to work, you must have the following:

You will first need to import the MySQL server CA Certificate into a Java truststore. A sample MySQL server CA Certificate is located in the 'SSL' subdirectory of the MySQL source distribution. This is what SSL will use to determine if you are communicating with a secure MySQL server.

To use Java's 'keytool' to create a truststore in the current directory , and import the server's CA certificate ('cacert.pem'), you can do the following (assuming that'keytool' is in your path. It's located in the 'bin' subdirectory of your JDK or JRE):

shell> keytool -import -alias mysqlServerCACert -file cacert.pem -keystore truststore

Keytool will respond with the following information:

Enter keystore password:  *********
Owner: EMAILADDRESS=walrus@example.com, CN=Walrus, O=MySQL AB, L=Orenburg, ST=Some
-State, C=RU
Issuer: EMAILADDRESS=walrus@example.com, CN=Walrus, O=MySQL AB, L=Orenburg, ST=Som
e-State, C=RU
Serial number: 0
Valid from: Fri Aug 02 16:55:53 CDT 2002 until: Sat Aug 02 16:55:53 CDT 2003
Certificate fingerprints:
         MD5:  61:91:A0:F2:03:07:61:7A:81:38:66:DA:19:C4:8D:AB
         SHA1: 25:77:41:05:D5:AD:99:8C:14:8C:CA:68:9C:2F:B8:89:C3:34:4D:6C
Trust this certificate? [no]:  yes
Certificate was added to keystore

You will then need to generate a client certificate, so that the MySQL server knows that it is talking to a secure client:

 shell> keytool -genkey -keyalg rsa -alias mysqlClientCertificate -keystore keystore 

Keytool will prompt you for the following information, and create a keystore named 'keystore' in the current directory.

You should respond with information that is appropriate for your situation:

Enter keystore password:  *********
What is your first and last name?
  [Unknown]:  Matthews
What is the name of your organizational unit?
  [Unknown]:  Software Development
What is the name of your organization?
  [Unknown]:  MySQL AB
What is the name of your City or Locality?
  [Unknown]:  Flossmoor
What is the name of your State or Province?
  [Unknown]:  IL
What is the two-letter country code for this unit?
  [Unknown]:  US
Is <CN=Matthews, OU=Software Development, O=MySQL AB,
 L=Flossmoor, ST=IL, C=US> correct?
  [no]:  y

Enter key password for <mysqlClientCertificate>
        (RETURN if same as keystore password):

Finally, to get JSSE to use the keystore and truststore that you have generated, you need to set the following system properties when you start your JVM, replacing 'path_to_keystore_file' with the full path to the keystore file you created, 'path_to_truststore_file' with the path to the truststore file you created, and using the appropriate password values for each property.


You will also need to set 'useSSL' to 'true' in your connection parameters for MySQL Connector/J, either by adding 'useSSL=true' to your URL, or by setting the property 'useSSL' to 'true' in the java.util.Properties instance you pass to DriverManager.getConnection().

You can test that SSL is working by turning on JSSE debugging (as detailed below), and look for the following key events:

 *** ClientHello, v3.1
 RandomCookie:  GMT: 1018531834 bytes = { 199, 148, 180, 215, 74, 12, 54, 244, 0, 168, 55, 103, 215, 64, 16, 138, 225, 190, 132, 153, 2, 217, 219, 239, 202, 19, 121, 78 }
 Session ID:  {}
 Cipher Suites:  { 0, 5, 0, 4, 0, 9, 0, 10, 0, 18, 0, 19, 0, 3, 0, 17 }
 Compression Methods:  { 0 }
 [write] MD5 and SHA1 hashes:  len = 59
 0000: 01 00 00 37 03 01 3D B6   90 FA C7 94 B4 D7 4A 0C  ...7..=.......J.
 0010: 36 F4 00 A8 37 67 D7 40   10 8A E1 BE 84 99 02 D9  6...7g.@........
 0020: DB EF CA 13 79 4E 00 00   10 00 05 00 04 00 09 00  ....yN..........
 0030: 0A 00 12 00 13 00 03 00   11 01 00                 ...........
 main, WRITE:  SSL v3.1 Handshake, length = 59
 main, READ:  SSL v3.1 Handshake, length = 74
 *** ServerHello, v3.1
 RandomCookie:  GMT: 1018577560 bytes = { 116, 50, 4, 103, 25, 100, 58, 202, 79, 185, 178, 100, 215, 66, 254, 21, 83, 187, 190, 42, 170, 3, 132, 110, 82, 148, 160, 92 }
 Session ID:  {163, 227, 84, 53, 81, 127, 252, 254, 178, 179, 68, 63, 182, 158, 30, 11, 150, 79, 170, 76, 255, 92, 15, 226, 24, 17, 177, 219, 158, 177, 187, 143}
 Cipher Suite:  { 0, 5 }
 Compression Method: 0
 %% Created:  [Session-1, SSL_RSA_WITH_RC4_128_SHA]
 [read] MD5 and SHA1 hashes:  len = 74
 0000: 02 00 00 46 03 01 3D B6   43 98 74 32 04 67 19 64  ...F..=.C.t2.g.d
 0010: 3A CA 4F B9 B2 64 D7 42   FE 15 53 BB BE 2A AA 03  :.O..d.B..S..*..
 0020: 84 6E 52 94 A0 5C 20 A3   E3 54 35 51 7F FC FE B2  .nR..\ ..T5Q....
 0030: B3 44 3F B6 9E 1E 0B 96   4F AA 4C FF 5C 0F E2 18  .D?.....O.L.\...
 0040: 11 B1 DB 9E B1 BB 8F 00   05 00                    ..........
 main, READ:  SSL v3.1 Handshake, length = 1712

JSSE provides debugging (to STDOUT) when you set the following system property: -Djavax.net.debug=all This will tell you what keystores and truststores are being used, as well as what is going on during the SSL handshake and certificate exchange. It will be helpful when trying to determine what is not working when trying to get an SSL connection to happen.

1.3.6. Using Master/Slave Replication with ReplicationConnection

Starting with Connector/J 3.1.7, we've made available a variant of the driver that will automatically send queries to a read/write master, or a failover or round-robin loadbalanced set of slaves based on the state of Connection.getReadOnly() .

An application signals that it wants a transaction to be read-only by calling Connection.setReadOnly(true), this "replication-aware" connection will use one of the slave connections, which are load-balanced per-vm using a round-robin scheme (a given connection is "sticky" to a slave unless that slave is removed from service). If you have a write transaction, or if you have a read that is "time-sensitive" (remember, replication in MySQL is asynchronous), set the connection to be not read-only, by calling Connection.setReadOnly(false) and the driver will ensure that further calls are sent to the "master" MySQL server. The driver takes care of propagating the current state of autocommit, isolation level, and catalog between all of the connections that it uses to accomplish this load balancing functionality.

To enable this functionality, use the " com.mysql.jdbc.ReplicationDriver " class when configuring your application server's connection pool or when creating an instance of a JDBC driver for your standalone application. Because it accepts the same URL format as the standard MySQL JDBC driver, ReplicationDriver does not currently work with java.sql.DriverManager -based connection creation unless it is the only MySQL JDBC driver registered with the DriverManager .

Here is a short, simple example of how ReplicationDriver might be used in a standalone application.

import java.sql.Connection;
import java.sql.ResultSet;
import java.util.Properties;

import com.mysql.jdbc.ReplicationDriver;

public class ReplicationDriverDemo {

    public static void main(String[] args) throws Exception {
        ReplicationDriver driver = new ReplicationDriver();

        Properties props = new Properties();

        // We want this for failover on the slaves
        props.put("autoReconnect", "true");

        // We want to load balance between the slaves
        props.put("roundRobinLoadBalance", "true");

        props.put("user", "foo");
        props.put("password", "bar");

        // Looks like a normal MySQL JDBC url, with a comma-separated list
        // of hosts, the first being the 'master', the rest being any number
        // of slaves that the driver will load balance against

        Connection conn =

        // Perform read/write work on the master
        // by setting the read-only flag to "false"

        conn.createStatement().executeUpdate("UPDATE some_table ....");

        // Now, do a query from a slave, the driver automatically picks one
        // from the list


        ResultSet rs = conn.createStatement().executeQuery("SELECT a,b,c FROM some_other_table");


1.4. Using Connector/J with J2EE and Other Java Frameworks

This section describes how to use Connector/J in several contexts.

1.4.1. General J2EE Concepts

This section provides general background on J2EE concepts that pertain to use of Connector/J. Understanding Connection Pooling

Connection pooling is a technique of creating and managing a pool of connections that are ready for use by any thread that needs them.

This technique of "pooling" connections is based on the fact that most applications only need a thread to have access to a JDBC connection when they are actively processing a transaction, which usually take only milliseconds to complete. When not processing a transaction, the connection would otherwise sit idle. Instead, connection pooling allows the idle connection to be used by some other thread to do useful work.

In practice, when a thread needs to do work against a MySQL or other database with JDBC, it requests a connection from the pool. When the thread is finished using the connection, it returns it to the pool, so that it may be used by any other threads that want to use it.

When the connection is "loaned out" from the pool, it is used exclusively by the thread that requested it. From a programming point of view, it is the same as if your thread called DriverManager.getConnection() every time it needed a JDBC connection, however with connection pooling, your thread may end up using either a new, or already-existing connection.

Connection pooling can greatly increase the performance of your Java application, while reducing overall resource usage. The main benefits to connection pooling are:

  • Reduced connection creation time

    While this is not usually an issue with the quick connection setup that MySQL offers compared to other databases, creating new JDBC connections still incurs networking and JDBC driver overhead that will be avoided if connections are "recycled."

  • Simplified programming model

    When using connection pooling, each individual thread can act as though it has created its own JDBC connection, allowing you to use straight-forward JDBC programming techniques.

  • Controlled resource usage

    If you don't use connection pooling, and instead create a new connection every time a thread needs one, your application's resource usage can be quite wasteful and lead to unpredictable behavior under load.

Remember that each connection to MySQL has overhead (memory, CPU, context switches, etc) on both the client and server side. Every connection limits how many resources there are available to your application as well as the MySQL server. Many of these resources will be used whether or not the connection is actually doing any useful work!

Connection pools can be tuned to maximize performance, while keeping resource utilization below the point where your application will start to fail rather than just run slower.

Luckily, Sun has standardized the concept of connection pooling in JDBC through the JDBC-2.0 "Optional" interfaces, and all major application servers have implementations of these APIs that work fine with MySQL Connector/J.

Generally, you configure a connection pool in your application server configuration files, and access it via the Java Naming and Directory Interface (JNDI). The following code shows how you might use a connection pool from an application deployed in a J2EE application server:

Example 12. Using a Connection Pool with a J2EE Application Server

import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;

import javax.naming.InitialContext;
import javax.sql.DataSource;

public class MyServletJspOrEjb {

    public void doSomething() throws Exception {
         * Create a JNDI Initial context to be able to
         *  lookup  the DataSource
         * In production-level code, this should be cached as
         * an instance or static variable, as it can
         * be quite expensive to create a JNDI context.
         * Note: This code only works when you are using servlets
         * or EJBs in a J2EE application server. If you are
         * using connection pooling in standalone Java code, you
         * will have to create/configure datasources using whatever
         * mechanisms your particular connection pooling library
         * provides.

        InitialContext ctx = new InitialContext();

          * Lookup the DataSource, which will be backed by a pool
          * that the application server provides. DataSource instances
          * are also a good candidate for caching as an instance
          * variable, as JNDI lookups can be expensive as well.

        DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/MySQLDB");

         * The following code is what would actually be in your
         * Servlet, JSP or EJB 'service' method...where you need
         * to work with a JDBC connection.

        Connection conn = null;
        Statement stmt = null;

        try {
            conn = ds.getConnection();

             * Now, use normal JDBC programming to work with
             * MySQL, making sure to close each resource when you're
             * finished with it, which allows the connection pool
             * resources to be recovered as quickly as possible

            stmt = conn.createStatement();
            stmt.execute("SOME SQL QUERY");

            stmt = null;

            conn = null;
        } finally {
             * close any jdbc instances here that weren't
             * explicitly closed during normal code path, so
             * that we don't 'leak' resources...

            if (stmt != null) {
                try {
                } catch (sqlexception sqlex) {
                    // ignore -- as we can't do anything about it here

                stmt = null;

            if (conn != null) {
                try {
                } catch (sqlexception sqlex) {
                    // ignore -- as we can't do anything about it here

                conn = null;

As shown in the example above, after obtaining the JNDI InitialContext, and looking up the DataSource, the rest of the code should look familiar to anyone who has done JDBC programming in the past.

The most important thing to remember when using connection pooling is to make sure that no matter what happens in your code (exceptions, flow-of-control, etc), connections, and anything created by them (statements, result sets, etc) are closed, so that they may be re-used, otherwise they will be "stranded," which in the best case means that the MySQL server resources they represent (buffers, locks, sockets, etc) may be tied up for some time, or worst case, may be tied up forever.

What's the Best Size for my Connection Pool?

As with all other configuration rules-of-thumb, the answer is "It depends." While the optimal size depends on anticipated load and average database transaction time, the optimum connection pool size is smaller than you might expect. If you take Sun's Java Petstore blueprint application for example, a connection pool of 15-20 connections can serve a relatively moderate load (600 concurrent users) using MySQL and Tomcat with response times that are acceptable.

To correctly size a connection pool for your application, you should create load test scripts with tools such as Apache JMeter or The Grinder, and load test your application.

An easy way to determine a starting point is to configure your connection pool's maximum number of connections to be "unbounded," run a load test, and measure the largest amount of concurrently used connections. You can then work backwards from there to determine what values of minimum and maximum pooled connections give the best performance for your particular application.

1.4.2. Using Connector/J with Tomcat

The following instructions are based on the instructions for Tomcat-5.x, available at http://jakarta.apache.org/tomcat/tomcat-5.0-doc/jndi-datasource-examples-howto.html which is current at the time this document was written.

First, install the .jar file that comes with Connector/J in $CATALINA_HOME/common/lib so that it is available to all applications installed in the container.

Next, Configure the JNDI DataSource by adding a declaration resource to $CATALINA_HOME/conf/server.xml in the context that defines your web application:

<Context ....>


  <Resource name="jdbc/MySQLDB"

  <!-- The name you used above, must match _exactly_ here!

       The connection pool will be bound into JNDI with the name

  <ResourceParams name="jdbc/MySQLDB">

    <!-- Don't set this any higher than max_connections on your
         MySQL server, usually this should be a 10 or a few 10's
         of connections, not hundreds or thousands -->


    <!-- You don't want to many idle connections hanging around
         if you can avoid it, only enough to soak up a spike in
         the load -->


    <!-- Don't use autoReconnect=true, it's going away eventually
         and it's a crutch for older connection pools that couldn't
         test connections. You need to decide if your application is
         supposed to deal with SQLExceptions (hint, it should), and
         how much of a performance penalty you're willing to pay
         to ensure 'freshness' of the connection -->

      <value>SELECT 1</value>

   <!-- The most conservative approach is to test connections
        before they're given to your application. For most applications
        this is okay, the query used above is very small and takes
        no real server resources to process, other than the time used
        to traverse the network.

        If you have a high-load application you'll need to rely on
        something else. -->


   <!-- Otherwise, or in addition to testOnBorrow, you can test
        while connections are sitting idle -->


    <!-- You have to set this value, otherwise even though
         you've asked connections to be tested while idle,
         the idle evicter thread will never run -->


    <!-- Don't allow connections to hang out idle too long,
         never longer than what wait_timeout is set to on the
         server...A few minutes or even fraction of a minute
         is sometimes okay here, it depends on your application
         and how much spikey load it will see -->


    <!-- Username and password used when connecting to MySQL -->



    <!-- Class name for the Connector/J driver -->


    <!-- The JDBC connection url for connecting to MySQL, notice
         that if you want to pass any other MySQL-specific parameters
         you should pass them here in the URL, setting them using the
         parameter tags above will have no effect, you will also
         need to use &amp; to separate parameter values as the
         ampersand is a reserved character in XML -->



In general, you should follow the installation instructions that come with your version of Tomcat, as the way you configure datasources in Tomcat changes from time-to-time, and unfortunately if you use the wrong syntax in your XML file, you will most likely end up with an exception similar to the following:

Error: java.sql.SQLException: Cannot load JDBC driver class 'null ' SQL
state: null 

1.4.3. Using Connector/J with JBoss

These instructions cover JBoss-4.x. To make the JDBC driver classes available to the application server, copy the .jar file that comes with Connector/J to the lib directory for your server configuration (which is usually called "default"). Then, in the same configuration directory, in the subdirectory named "deploy", create a datasource configuration file that ends with "-ds.xml", which tells JBoss to deploy this file as a JDBC Datasource. The file should have the following contents:

        <!-- This connection pool will be bound into JNDI with the name
             "java:/MySQLDB" -->



        <!-- Don't set this any higher than max_connections on your
         MySQL server, usually this should be a 10 or a few 10's
         of connections, not hundreds or thousands -->


        <!-- Don't allow connections to hang out idle too long,
         never longer than what wait_timeout is set to on the
         server...A few minutes is usually okay here,
         it depends on your application
         and how much spikey load it will see -->


        <!-- If you're using Connector/J 3.1.8 or newer, you can use
             our implementation of these to increase the robustness
             of the connection pool. -->



1.5. Diagnosing Connector/J Problems

This section describes how to solve problems that you may encounter when using Connector/J.

1.5.1. Common Problems and Solutions

There are a few issues that seem to be commonly encountered often by users of MySQL Connector/J. This section deals with their symptoms, and their resolutions. If you have further issues, see the "SUPPORT" section.


When I try to connect to the database with MySQL Connector/J, I get the following exception:

SQLException: Server configuration denies access to data source
SQLState: 08001
VendorError: 0

What's going on? I can connect just fine with the MySQL command-line client.


MySQL Connector/J must use TCP/IP sockets to connect to MySQL, as Java does not support Unix Domain Sockets. Therefore, when MySQL Connector/J connects to MySQL, the security manager in MySQL server will use its grant tables to determine whether or not the connection should be allowed.

You must add grants to allow this to happen. The following is an example of how to do this (but not the most secure).

From the mysql command-line client, logged in as a user that can grant privileges, issue the following command:

                '[user]'@'[hostname]' identified by

replacing [dbname] with the name of your database, [user] with the user name, [hostname] with the host that MySQL Connector/J will be connecting from, and [password] with the password you want to use. Be aware that RedHat Linux is broken with respect to the hostname portion for the case when you are connecting from localhost. You need to use "localhost.localdomain" for the [hostname] value in this case. Follow this by issuing the "FLUSH PRIVILEGES" command.


Testing your connectivity with the "mysql" command-line client will not work unless you add the "--host" flag, and use something other than "localhost" for the host. The "mysql" command-line client will use Unix domain sockets if you use the special hostname "localhost". If you are testing connectivity to "localhost", use "" as the hostname instead.


If you don't understand what the 'GRANT' command does, or how it works, you should read and understand the 'General Security Issues and the MySQL Access Privilege System' section of the MySQL manual before attempting to change privileges.

Changing privileges and permissions improperly in MySQL can potentially cause your server installation to not have optimal security properties.


My application throws a SQLException 'No Suitable Driver'. Why is this happening?


One of two things are happening. Either the driver is not in your CLASSPATH (see the "INSTALLATION" section above), or your URL format is incorrect (see "Developing Applications with MySQL Connector/J").


I'm trying to use MySQL Connector/J in an applet or application and I get an exception similar to:

SQLException: Cannot connect to MySQL server on host:3306.
Is there a MySQL server running on the machine/port you
are trying to connect to?

SQLState: 08S01
VendorError: 0 


Either you're running an Applet, your MySQL server has been installed with the "--skip-networking" option set, or your MySQL server has a firewall sitting in front of it.

Applets can only make network connections back to the machine that runs the web server that served the .class files for the applet. This means that MySQL must run on the same machine (or you must have some sort of port re-direction) for this to work. This also means that you will not be able to test applets from your local file system, you must always deploy them to a web server.

MySQL Connector/J can only communicate with MySQL using TCP/IP, as Java does not support Unix domain sockets. TCP/IP communication with MySQL might be affected if MySQL was started with the "--skip-networking" flag, or if it is firewalled.

If MySQL has been started with the "--skip-networking" option set (the Debian Linux package of MySQL server does this for example), you need to comment it out in the file /etc/mysql/my.cnf or /etc/my.cnf. Of course your my.cnf file might also exist in the "data" directory of your MySQL server, or anywhere else (depending on how MySQL was compiled for your system). Binaries created by MySQL AB always look in /etc/my.cnf and [datadir]/my.cnf. If your MySQL server has been firewalled, you will need to have the firewall configured to allow TCP/IP connections from the host where your Java code is running to the MySQL server on the port that MySQL is listening to (by default, 3306).


I have a servlet/application that works fine for a day, and then stops working overnight


MySQL closes connections after 8 hours of inactivity. You either need to use a connection pool that handles stale connections or use the "autoReconnect" parameter (see "Developing Applications with MySQL Connector/J").

Also, you should be catching SQLExceptions in your application and dealing with them, rather than propagating them all the way until your application exits, this is just good programming practice. MySQL Connector/J will set the SQLState (see java.sql.SQLException.getSQLState() in your APIDOCS) to "08S01" when it encounters network-connectivity issues during the processing of a query. Your application code should then attempt to re-connect to MySQL at this point.

The following (simplistic) example shows what code that can handle these exceptions might look like:

Example 13. Example of transaction with retry logic

public void doBusinessOp() throws SQLException {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;

        // How many times do you want to retry the transaction
        // (or at least _getting_ a connection)?
        int retryCount = 5;

        boolean transactionCompleted = false;

        do {
            try {
                conn = getConnection(); // assume getting this from a
                                        // javax.sql.DataSource, or the
                                        // java.sql.DriverManager


                // Okay, at this point, the 'retry-ability' of the
                // transaction really depends on your application logic,
                // whether or not you're using autocommit (in this case
                // not), and whether you're using transacational storage
                // engines
                // For this example, we'll assume that it's _not_ safe
                // to retry the entire transaction, so we set retry count
                // to 0 at this point
                // If you were using exclusively transaction-safe tables,
                // or your application could recover from a connection going
                // bad in the middle of an operation, then you would not
                // touch 'retryCount' here, and just let the loop repeat
                // until retryCount == 0.
                retryCount = 0;

                stmt = conn.createStatement();

                String query = "SELECT foo FROM bar ORDER BY baz";

                rs = stmt.executeQuery(query);

                while (rs.next()) {

                rs = null;

                stmt = null;

                conn = null;

                transactionCompleted = true;
            } catch (SQLException sqlEx) {

                // The two SQL states that are 'retry-able' are 08S01
                // for a communications error, and 41000 for deadlock.
                // Only retry if the error was due to a stale connection,
                // communications problem or deadlock

                String sqlState = sqlEx.getSQLState();

                if ("08S01".equals(sqlState) || "41000".equals(sqlState)) {
                } else {
                    retryCount = 0;
            } finally {
                if (rs != null) {
                    try {
                    } catch (SQLException sqlEx) {
                        // You'd probably want to log this . . .

                if (stmt != null) {
                    try {
                    } catch (SQLException sqlEx) {
                        // You'd probably want to log this as well . . .

                if (conn != null) {
                    try {
                        // If we got here, and conn is not null, the
                        // transaction should be rolled back, as not
                        // all work has been done

                        try {
                        } finally {
                    } catch (SQLException sqlEx) {
                        // If we got an exception here, something
                        // pretty serious is going on, so we better
                        // pass it up the stack, rather than just
                        // logging it. . .

                        throw sqlEx;
        } while (!transactionCompleted && (retryCount > 0));


I'm trying to use JDBC-2.0 updatable result sets, and I get an exception saying my result set is not updatable.


Because MySQL does not have row identifiers, MySQL Connector/J can only update result sets that have come from queries on tables that have at least one primary key, the query must select all of the primary key(s) and the query can only span one table (i.e. no joins). This is outlined in the JDBC specification.

1.5.2. How to Report Bugs or Problems

The normal place to report bugs is http://bugs.mysql.com/, which is the address for our bugs database. This database is public, and can be browsed and searched by anyone. If you log in to the system, you will also be able to enter new reports.

If you have found a sensitive security bug in MySQL, you can send email to security@mysql.com.

Writing a good bug report takes patience, but doing it right the first time saves time both for us and for yourself. A good bug report, containing a full test case for the bug, makes it very likely that we will fix the bug in the next release.

This section will help you write your report correctly so that you don't waste your time doing things that may not help us much or at all.

If you have a repeatable bug report, please report it to the bugs database at http://bugs.mysql.com/.

Any bug that we are able to repeat has a high chance of being fixed in the next MySQL release.

To report other problems, you can use one of the MySQL mailing lists.

Remember that it is possible for us to respond to a message containing too much information, but not to one containing too little. People often omit facts because they think they know the cause of a problem and assume that some details don't matter.

A good principle is this: If you are in doubt about stating something, state it. It is faster and less troublesome to write a couple more lines in your report than to wait longer for the answer if we must ask you to provide information that was missing from the initial report.

The most common errors made in bug reports are (a) not including the version number of Connector/J or MySQL used, and (b) not fully describing the platform on which Connector/J is installed (including the JVM version, and the platform type and version number that MySQL itself is installed on).

This is highly relevant information, and in 99 cases out of 100, the bug report is useless without it. Very often we get questions like, ``Why doesn't this work for me?'' Then we find that the feature requested wasn't implemented in that MySQL version, or that a bug described in a report has already been fixed in newer MySQL versions.

Sometimes the error is platform-dependent; in such cases, it is next to impossible for us to fix anything without knowing the operating system and the version number of the platform.

If at all possible, you should create a repeatable, stanalone testcase that doesn't involve any third-party classes.

To streamline this process, we ship a base class for testcases with Connector/J, named ' com.mysql.jdbc.util.BaseBugReport '. To create a testcase for Connector/J using this class, create your own class that inherits from com.mysql.jdbc.util.BaseBugReport and override the methods setUp(), tearDown() and runTest ().

In the setUp() method, create code that creates your tables, and populates them with any data needed to demonstrate the bug.

In the runTest () method, create code that demonstrates the bug using the tables and data you created in the 'setUp' method.

In the tearDown() method, drop any tables you created in the setUp() method.

In any of the above three methods, you should use one of the variants of the getConnection () method to create a JDBC connection to MySQL:

  • getConnection() - Provides a connection to the JDBC URL specified in getUrl(). If a connection already exists, that connection is returned, otherwise a new connection is created.

  • getNewConnection() - Use this if you need to get a new connection for your bug report (i.e. there's more than one connection involved).

  • getConnection(String url) - Returns a connection using the given URL.

  • getConnection(String url, Properties props) - Returns a connection using the given URL and properties.

If you need to use a JDBC URL that is different than 'jdbc:mysql:///test', then override the method getUrl() as well.

Use the assertTrue(boolean expression) and assertTrue(String failureMessage, boolean expression) methods to create conditions that must be met in your testcase demonstrating the behavior you are expecting (vs. the behavior you are observing, which is why you are most likely filing a bug report).

Finally, create a main () method that creates a new instance of your testcase, and calls the run method:

public static void main(String[] args) throws Exception {
      new MyBugReport().run();

Once you have finished your testcase, and have verified that it demonstrates the bug you are reporting, upload it with your bug report to http://bugs.mysql.com/.

1.6. Changelog

# Changelog
# $Id: CHANGES,v 2005/05/12 15:25:54 mmatthews Exp $

05-17-05 - Version 3.2.1-alpha

    - Autoreconnect functionality (i.e. autoReconnect=true) is now deprecated.
      An exception will be thrown if you try and use it, use 
      'enableDeprecatedAutoreconnect=true' to still use autoReconnect. However
      this feature will be removed in Connector/J 3.3, see the manual for 
      solutions that don't require autoReconnect to be used.

    - Driver now checks if server variable 'init_connect' is set, and if so
      checks autocommit setting, and applies it.
    - If connected to server > 5.0.x, and Statement.setFetchSize( > 0), the
      driver will try and use server prepared statements and fetch
      statements using result set 'cursors'.
    - ServerPreparedStatements now correctly 'stream' BLOB/CLOB data to the
      server. You can configure the threshold chunk size using the
      JDBC URL property 'blobSendChunkSize' (the default is one megabyte).
    - Support sql mode NO_BACKSLASH_ESCAPES with non-server-side prepared

12-23-04 - Version 3.2.0-alpha

    - Fixed incorrect return values from DatabaseMetaData.supportsCatalogIn*().
    - Support for 'cursor' based result sets when using ServerPreparedStatements
      and MySQL 5.0 or newer. Result set needs to be forward-only, and a non-zero
      fetch size for this feature to be enabled.
    - Refactoring of where logic for prepared statement, server-prepared 
      statement lives.

10-07-05 - Version 3.1.11-stable

    - Fixed BUG#11629 - Spurious "!" on console when character
      encoding is "utf8".
    - Fixed statements generated for testcases missing ";" for
      "plain" statements.
    - Fixed BUG#11663 - Incorrect generation of testcase scripts 
      for server-side prepared statements.
    - Fixed regression caused by fix for BUG#11552 that caused driver
      to return incorrect values for unsigned integers when those 
      integers where within the range of the positive signed type.
    - Moved source code to svn repo.
    - Fixed BUG#11797 - Escape tokenizer doesn't respect stacked single quotes
      for escapes.
    - GEOMETRY type not recognized when using server-side prepared statements.
    - Fixed BUG#11879 -- ReplicationConnection won't switch to slave, throws 
      "Catalog can't be null" exception.
    - Fixed BUG#12218, properties shared between master and slave with 
      replication connection.
    - Fixed BUG#10630, Statement.getWarnings() fails with NPE if statement 
      has been closed.
    - Only get char[] from SQL in PreparedStatement.ParseInfo() when needed.
    - Fixed BUG#12104 - Geometry types not handled with server-side prepared 
    - Fixed BUG#11614 - StringUtils.getBytes() doesn't work when using 
      multibyte character encodings and a length in  _characters_ is 
    - Fixed BUG#11798 - Pstmt.setObject(...., Types.BOOLEAN) throws exception.
    - Fixed BUG#11976 - maxPerformance.properties mis-spells 
    - Fixed BUG#11575 -- DBMD.storesLower/Mixed/UpperIdentifiers()
      reports incorrect values for servers deployed on Windows.
    - Fixed BUG#11190 - ResultSet.moveToCurrentRow() fails to work when 
      preceeded by a call to ResultSet.moveToInsertRow().
    - Fixed BUG#11115, VARBINARY data corrupted when using server-side
      prepared statements and .setBytes().

    - Fixed BUG#12229 - explainSlowQueries hangs with server-side
      prepared statements.
    - Fixed BUG#11498 - Escape processor didn't honor strings demarcated
      with double quotes.
    - Lifted restriction of changing streaming parameters with server-side
      prepared statements. As long as _all_ streaming parameters were set
      before execution, .clearParameters() does not have to be called. 
      (due to limitation of client/server protocol, prepared statements
       can not reset _individual_ stream data on the server side).
    - Reworked Field class, *Buffer, and MysqlIO to be aware of field
      lengths > Integer.MAX_VALUE.
    - Updated DBMD.supportsCorrelatedQueries() to return true for versions > 
      4.1, supportsGroupByUnrelated() to return true and 
      getResultSetHoldability() to return HOLD_CURSORS_OVER_COMMIT.
    - Fixed BUG#12541 - Handling of catalog argument in 
      DatabaseMetaData.getIndexInfo(), which also means changes to the following
      methods in DatabaseMetaData:
    - getBestRowIdentifier()
    - getColumns()
    - getCrossReference()
    - getExportedKeys()
    - getImportedKeys()
    - getIndexInfo()
    - getPrimaryKeys()
    - getProcedures() (and thus indirectly getProcedureColumns())
    - getTables()
      The "catalog" argument in all of these methods now behaves in the following
        - Specifying NULL means that catalog will not be used to filter the
          results (thus all databases will be searched), unless you've
          set "nullCatalogMeansCurrent=true" in your JDBC URL properties.
        - Specifying "" means "current" catalog, even though this isn't quite
          JDBC spec compliant, it's there for legacy users.
        - Specifying a catalog works as stated in the API docs.
        - Made Connection.clientPrepare() available from "wrapped" connections
          in the jdbc2.optional package (connections built by 
          ConnectionPoolDataSource instances).
    - Added Connection.isMasterConnection() for clients to be able to determine
      if a multi-host master/slave connection is connected to the first host
      in the list.
    - Fixed BUG#12753 - Tokenizer for "=" in URL properties was causing
      sessionVariables=.... to be parameterized incorrectly.

    - Fixed BUG#11781, foreign key information that is quoted is 
      parsed incorrectly when DatabaseMetaData methods use that
    - The "sendBlobChunkSize" property is now clamped to "max_allowed_packet"
      with consideration of stream buffer size and packet headers to avoid
      PacketTooBigExceptions when "max_allowed_packet" is similar in size
      to the default "sendBlobChunkSize" which is 1M.
    - CallableStatement.clearParameters() now clears resources associated
      with INOUT/OUTPUT parameters as well as INPUT parameters.
    - Fixed BUG#12417 - Connection.prepareCall() is database name 
      case-sensitive (on Windows systems).
    - Fixed BUG#12752 - Cp1251 incorrectly mapped to win1251 for 
      servers newer than 4.0.x.
    - Fixed BUG#12970 - java.sql.Types.OTHER returned for 
      BINARY and VARBINARY columns when using 
    - ServerPreparedStatement.getBinding() now checks if the statement
      is closed before attempting to reference the list of parameter
      bindings, to avoid throwing a NullPointerException.
    - Fixed BUG#13277 - ResultSetMetaData from 
      Statement.getGeneratedKeys() caused NullPointerExceptions to be
      thrown whenever a method that required a connection reference
      was called.
    - Backport of Field class, ResultSetMetaData.getColumnClassName(),
      and ResultSet.getObject(int) changes from 5.0 branch to fix
      behavior surrounding VARCHAR BINARY/VARBINARY and related
    - Fixed NullPointerException when converting "catalog" parameter
      in many DatabaseMetaDataMethods to byte[]s (for the result set)
      when the parameter is null. ("null" isn't technically allowed
      by the JDBC specification, but we've historically allowed it).
    - Backport of VAR[BINARY|CHAR] [BINARY] types detection from 
      5.0 branch.
    - Read response in MysqlIO.sendFileToServer(), even if the 
      local file can't be opened, otherwise next query issued
      will fail, because it's reading the response to the empty
      LOAD DATA INFILE packet sent to the server.
    - Workaround for BUG#13374 - ResultSet.getStatement() 
      on closed result set returns NULL (as per JDBC 4.0 spec,
      but not backwards-compatible). Set the connection property
      "retainStatementAfterResultSetClose" to "true" to be able
      to retrieve a ResultSet's statement after the ResultSet has
      been closed via .getStatement() (the default is "false", to
      be JDBC-compliant and to reduce the chance that code using
      JDBC leaks Statement instances).
    - Fixed BUG#13453 - URL configuration parameters don't allow
      '&' or '=' in their values. The JDBC driver now parses 
      configuration parameters as if they are encoded using the 
      application/x-www-form-urlencoded format as specified
      by java.net.URLDecoder - 
      If the '%' character is present in a configuration property,
      it must now be represented as %25, which is the encoded form
      of '%' when using application/x-www-form-urlencoded encoding.
    - The configuration property "sessionVariables" now allows you to
      specify variables that start with the "@" sign.
    - Fixed BUG#13043 - when 'gatherPerfMetrics' is enabled for 
      servers older than 4.1.0, a NullPointerException is thrown from 
      the constructor of ResultSet if the query doesn't use any tables.

06-23-05 - Version 3.1.10-stable

    - Fixed connecting without a database specified raised an exception
      in MysqlIO.changeDatabaseTo().
    - Initial implemention of ParameterMetadata for 
      PreparedStatement.getParameterMetadata(). Only works fully
      for CallableStatements, as current server-side prepared statements
      return every parameter as a VARCHAR type.
06-22-05 - Version 3.1.9-stable

    - Overhaul of character set configuration, everything now
      lives in a properties file.
    - Driver now correctly uses CP932 if available on the server
      for Windows-31J, CP932 and MS932 java encoding names, 
      otherwise it resorts to SJIS, which is only a close 
      approximation. Currently only MySQL-5.0.3 and newer (and
      MySQL-4.1.12 or .13, depending on when the character set
      gets backported) can reliably support any variant of CP932.

    - Fixed BUG#9064 - com.mysql.jdbc.PreparedStatement.ParseInfo 
      does unnecessary call to toCharArray().

    - Fixed Bug#10144 - Memory leak in ServerPreparedStatement if 
      serverPrepare() fails.
    - Actually write manifest file to correct place so it ends up
      in the binary jar file.

    - Added "createDatabaseIfNotExist" property (default is "false"),
      which will cause the driver to ask the server to create the 
      database specified in the URL if it doesn't exist. You must have
      the appropriate privileges for database creation for this to

    - Fixed BUG#10156 - Unsigned SMALLINT treated as signed for ResultSet.getInt(),
      fixed all cases for UNSIGNED integer values and server-side prepared statements,
      as well as ResultSet.getObject() for UNSIGNED TINYINT.
    - Fixed BUG#10155, double quotes not recognized when parsing 
      client-side prepared statements.
    - Made enableStreamingResults() visible on 
    - Made ServerPreparedStatement.asSql() work correctly so auto-explain
      functionality would work with server-side prepared statements.
    - Made JDBC2-compliant wrappers public in order to allow access to
      vendor extensions.
    - Cleaned up logging of profiler events, moved code to dump a profiler
      event as a string to com.mysql.jdbc.log.LogUtils so that third
      parties can use it.
    - DatabaseMetaData.supportsMultipleOpenResults() now returns true. The
      driver has supported this for some time, DBMD just missed that fact.
    - Fixed BUG#10310 - Driver doesn't support {?=CALL(...)} for calling
      stored functions. This involved adding support for function retrieval
      to DatabaseMetaData.getProcedures() and getProcedureColumns() as well.
    - Fixed BUG#10485, SQLException thrown when retrieving YEAR(2) 
      with ResultSet.getString(). The driver will now always treat YEAR types
      as java.sql.Dates and return the correct values for getString(). 
      Alternatively, the "yearIsDateType" connection property can be set to
      "false" and the values will be treated as SHORTs.
    - The datatype returned for TINYINT(1) columns when "tinyInt1isBit=true" 
      (the default) can be switched between Types.BOOLEAN and Types.BIT
      using the new configuration property "transformedBitIsBoolean", which
      defaults to "false". If set to "false" (the default), 
      DatabaseMetaData.getColumns() and ResultSetMetaData.getColumnType() 
      will return Types.BOOLEAN for TINYINT(1) columns. If "true", 
      Types.BOOLEAN will be returned instead. Irregardless of this configuration
      property, if "tinyInt1isBit" is enabled, columns with the type TINYINT(1)
      will be returned as java.lang.Boolean instances from 
      ResultSet.getObject(..), and ResultSetMetaData.getColumnClassName()
      will return "java.lang.Boolean".

    - Fixed BUG#10496 - SQLException is thrown when using property 
      "characterSetResults" with cp932 or eucjpms.
    - Reorganized directory layout, sources now in "src" folder,
      don't pollute parent directory when building, now output goes
      to "./build", distribution goes to "./dist".
    - Added support/bug hunting feature that generates .sql test
      scripts to STDERR when "autoGenerateTestcaseScript" is set
      to "true".
    - Fixed BUG#10850 - 0-length streams not sent to server when
      using server-side prepared statements.
    - Setting "cachePrepStmts=true" now causes the Connection to also 
      cache the check the driver performs to determine if a prepared 
      statement can be server-side or not, as well as caches server-side
      prepared statements for the lifetime of a connection. As before,
      the "prepStmtCacheSize" parameter controls the size of these
    - Try to handle OutOfMemoryErrors more gracefully. Although not
      much can be done, they will in most cases close the connection
      they happened on so that further operations don't run into 
      a connection in some unknown state. When an OOM has happened, 
      any further operations on the connection will fail with a 
      "Connection closed" exception that will also list the OOM exception
      as the reason for the implicit connection close event.
    - Don't send COM_RESET_STMT for each execution of a server-side
      prepared statement if it isn't required.
    - Driver detects if you're running MySQL-5.0.7 or later, and does
      not scan for "LIMIT ?[,?]" in statements being prepared, as the
      server supports those types of queries now.
    - Fixed BUG#11115, Varbinary data corrupted when using server-side
      prepared statements and ResultSet.getBytes().
    - Connection.setCatalog() is now aware of the "useLocalSessionState"
      configuration property, which when set to true will prevent
      the driver from sending "USE ..." to the server if the requested
      catalog is the same as the current catalog.
    - Added the following configuration bundles, use one or many via
      the "useConfigs" configuration property:
        * maxPerformance -- maximum performance without being reckless
        * solarisMaxPerformance -- maximum performance for Solaris,
                                   avoids syscalls where it can
        * 3-0-Compat -- Compatibility with Connector/J 3.0.x functionality
    - Added "maintainTimeStats" configuration property (defaults to "true"),
      which tells the driver whether or not to keep track of the last query time
      and the last successful packet sent to the server's time. If set to
      false, removes two syscalls per query.
    - Fixed BUG#11259, autoReconnect ping causes exception on connection 
    - Fixed BUG#11360 Connector/J dumping query into SQLException twice
    - Fixed PreparedStatement.setClob() not accepting null as a parameter.
    - Fixed BUG#11411 - Production package doesn't include JBoss integration 
    - Removed nonsensical "costly type conversion" warnings when using 
      usage advisor.

04-14-05 - Version 3.1.8-stable

    - Fixed DatabaseMetaData.getTables() returning views when they were
      not asked for as one of the requested table types.

    - Added support for new precision-math DECIMAL type in MySQL >= 5.0.3.

    - Fixed ResultSet.getTime() on a NULL value for server-side prepared
      statements throws NPE.

    - Made Connection.ping() a public method.

    - Fixed Bug#8868, DATE_FORMAT() queries returned as BLOBs from getObject().

    - ServerPreparedStatements now correctly 'stream' BLOB/CLOB data to the
      server. You can configure the threshold chunk size using the
      JDBC URL property 'blobSendChunkSize' (the default is one megabyte).

    - BlobFromLocator now uses correct identifier quoting when generating
      prepared statements.

    - Server-side session variables can be preset at connection time by
      passing them as a comma-delimited list for the connection property

    - Fixed regression in ping() for users using autoReconnect=true.

    - Fixed BUG#9040 - PreparedStatement.addBatch() doesn't work with server-side
      prepared statements and streaming BINARY data.

    - Fixed BUG#8800 - DBMD.supportsMixedCase*Identifiers() returns wrong
      value on servers running on case-sensitive filesystems.

    - Fixed BUG#9206, can not use 'UTF-8' for characterSetResults
      configuration property.

    - Fixed BUG#9236, a continuation of BUG#8868, where functions used in queries
      that should return non-string types when resolved by temporary tables suddenly
      become opaque binary strings (work-around for server limitation). Also fixed
      fields with type of CHAR(n) CHARACTER SET BINARY to return correct/matching
      classes for RSMD.getColumnClassName() and ResultSet.getObject().

    - Fixed BUG#8792 - DBMD.supportsResultSetConcurrency() not returning
      true for forward-only/read-only result sets (we obviously support this).

    - Fixed BUG#8803, 'DATA_TYPE' column from DBMD.getBestRowIdentifier()
      causes ArrayIndexOutOfBoundsException when accessed (and in fact, didn't
      return any value).

    - Check for empty strings ('') when converting char/varchar column data to numbers,
      throw exception if 'emptyStringsConvertToZero' configuration property is set
      to 'false' (for backwards-compatibility with 3.0, it is now set to 'true'
      by default, but will most likely default to 'false' in 3.2).

    - Fixed BUG#9320 - PreparedStatement.getMetaData() inserts blank row in database
      under certain conditions when not using server-side prepared statements.

    - Connection.canHandleAsPreparedStatement() now makes 'best effort' to distinguish
      LIMIT clauses with placeholders in them from ones without in order to have fewer
      false positives when generating work-arounds for statements the server cannot
      currently handle as server-side prepared statements.

    - Fixed build.xml to not compile log4j logging if log4j not available.

    - Added support for the c3p0 connection pool's (http://c3p0.sf.net/)
      validation/connection checker interface which uses the lightweight
      'COM_PING' call to the server if available. To use it, configure your
      c3p0 connection pool's 'connectionTesterClassName' property to use

    - Better detection of LIMIT inside/outside of quoted strings so that
      the driver can more correctly determine whether a prepared statement
      can be prepared on the server or not.

    - Fixed BUG#9319 - Stored procedures with same name in
      different databases confuse the driver when it tries to determine
      parameter counts/types.

    - Added finalizers to ResultSet and Statement implementations to be JDBC
      spec-compliant, which requires that if not explicitly closed, these
      resources should be closed upon garbage collection.

    - Fixed BUG#9682 - Stored procedures with DECIMAL parameters with
      storage specifications that contained "," in them would fail.

    - PreparedStatement.setObject(int, Object, int type, int scale) now
      uses scale value for BigDecimal instances.

    - Fixed BUG#9704 - Statement.getMoreResults() could throw NPE when
      existing result set was .close()d.

    - The performance metrics feature now gathers information about
      number of tables referenced in a SELECT.

    - The logging system is now automatically configured. If the value has
      been set by the user, via the URL property "logger" or the system
      property "com.mysql.jdbc.logger", then use that, otherwise, autodetect
      it using the following steps:

         Log4j, if it's available,
         Then JDK1.4 logging,
         Then fallback to our STDERR logging.

    - Fixed BUG#9778, DBMD.getTables() shouldn't return tables if views
      are asked for, even if the database version doesn't support views.

    - Fixed driver not returning 'true' for '-1' when ResultSet.getBoolean()
      was called on result sets returned from server-side prepared statements.

    - Added a Manifest.MF file with implementation information to the .jar

    - More tests in Field.isOpaqueBinary() to distinguish opaque binary (i.e.
      fields with type CHAR(n) and CHARACTER SET BINARY) from output of
      various scalar and aggregate functions that return strings.

    - Fixed BUG#9917 - Should accept null for catalog (meaning use current)
      in DBMD methods, even though it's not JDBC-compliant for legacy's sake.
      Disable by setting connection property "nullCatalogMeansCurrent" to "false"
      (which will be the default value in C/J 3.2.x).

    - Fixed BUG#9769 - Should accept null for name patterns in DBMD (meaning "%"),
      even though it isn't JDBC compliant, for legacy's sake. Disable by setting
      connection property "nullNamePatternMatchesAll" to "false" (which will be
      the default value in C/J 3.2.x).

02-18-05 - Version 3.1.7-stable

    - Fixed BUG#7686, Timestamp key column data needed "_binary'"
      stripped for UpdatableResultSet.refreshRow().

    - Fixed BUG#7715 - Timestamps converted incorrectly to strings
      with Server-side prepared statements and updatable result sets.

    - Detect new sql_mode variable in string form (it used to be
      integer) and adjust quoting method for strings appropriately.

    - Added 'holdResultsOpenOverStatementClose' property (default is
      false), that keeps result sets open over statement.close() or new
      execution on same statement (suggested by Kevin Burton).

    - Fixed BUG#7952 -- Infinite recursion when 'falling back' to master
      in failover configuration.

    - Disable multi-statements (if enabled) for MySQL-4.1 versions prior
      to version 4.1.10 if the query cache is enabled, as the server
      returns wrong results in this configuration.

    - Fixed duplicated code in configureClientCharset() that prevented
      useOldUTF8Behavior=true from working properly.

    - Removed 'dontUnpackBinaryResults' functionality, the driver now
      always stores results from server-side prepared statements as-is
      from the server and unpacks them on demand.

    - Fixed BUG#8096 where emulated locators corrupt binary data
      when using server-side prepared statements.

    - Fixed synchronization issue with
      ServerPreparedStatement.serverPrepare() that could cause
      deadlocks/crashes if connection was shared between threads.

    - By default, the driver now scans SQL you are preparing via all
      variants of Connection.prepareStatement() to determine if it is a
      supported type of statement to prepare on the server side, and if
      it is not supported by the server, it instead prepares it as a
      client-side emulated prepared statement (BUG#4718). You can
      disable this by passing 'emulateUnsupportedPstmts=false' in your
      JDBC URL.

    - Remove _binary introducer from parameters used as in/out
      parameters in CallableStatement.

    - Always return byte[]s for output parameters registered as *BINARY.

    - Send correct value for 'boolean' "true" to server for
      PreparedStatement.setObject(n, "true", Types.BIT).

    - Fixed bug with Connection not caching statements from
      prepareStatement() when the statement wasn't a server-side
      prepared statement.

    - Choose correct 'direction' to apply time adjustments when both
      client and server are in GMT timezone when using
      ResultSet.get(..., cal) and PreparedStatement.set(...., cal).

    - Added 'dontTrackOpenResources' option (default is false, to be
      JDBC compliant), which helps with memory use for non-well-behaved
      apps (i.e applications which don't close Statements when they

    - Fixed BUG#8428 - ResultSet.getString() doesn't maintain format
      stored on server, bug fix only enabled when 'noDatetimeStringSync'
      property is set to 'true' (the default is 'false').

    - Fixed NPE in ResultSet.realClose() when using usage advisor and
      result set was already closed.

    - Fixed BUG#8487 - PreparedStatements not creating streaming result

    - Don't pass NULL to String.valueOf() in
      ResultSet.getNativeConvertToString(), as it stringifies it (i.e.
      returns "null"), which is not correct for the method in question.

    - Fixed BUG#8484 - ResultSet.getBigDecimal() throws exception
      when rounding would need to occur to set scale. The driver now
      chooses a rounding mode of 'half up' if non-rounding
      BigDecimal.setScale() fails.

    - Added 'useLocalSessionState' configuration property, when set to
      'true' the JDBC driver trusts that the application is well-behaved
      and only sets autocommit and transaction isolation levels using
      the methods provided on java.sql.Connection, and therefore can
      manipulate these values in many cases without incurring
      round-trips to the database server.

    - Added enableStreamingResults() to Statement for connection pool
      implementations that check Statement.setFetchSize() for
      specification-compliant values. Call Statement.setFetchSize(>=0)
      to disable the streaming results for that statement.

    - Added support for BIT type in MySQL-5.0.3. The driver will treat
      BIT(1-8) as the JDBC standard BIT type (which maps to
      java.lang.Boolean), as the server does not currently send enough
      information to determine the size of a bitfield when < 9 bits are
      declared. BIT(>9) will be treated as VARBINARY, and will return
      byte[] when getObject() is called.

12-23-04 - Version 3.1.6-stable

    - Fixed hang on SocketInputStream.read() with Statement.setMaxRows() and
      multiple result sets when driver has to truncate result set directly,
      rather than tacking a 'LIMIT n' on the end of it.

    - Fixed BUG#7026 - DBMD.getProcedures() doesn't respect catalog parameter.

12-02-04 - Version 3.1.5-gamma

    - Fix comparisons made between string constants and dynamic strings that
      are either toUpperCase()d or toLowerCase()d to use Locale.ENGLISH, as
      some locales 'override' case rules for English. Also use
      StringUtils.indexOfIgnoreCase() instead of .toUpperCase().indexOf(),
      avoids creating a very short-lived transient String instance.

    - Fixed BUG#5235 - Server-side prepared statements did not honor
      'zeroDateTimeBehavior' property, and would cause class-cast
      exceptions when using ResultSet.getObject(), as the all-zero string
      was always returned.

    - Fixed batched updates with server prepared statements weren't looking if
      the types had changed for a given batched set of parameters compared
      to the previous set, causing the server to return the error
      'Wrong arguments to mysql_stmt_execute()'.

    - Handle case when string representation of timestamp contains trailing '.'
      with no numbers following it.

    - Fixed BUG#5706 - Inefficient detection of pre-existing string instances
      in ResultSet.getNativeString().

    - Don't throw exceptions for Connection.releaseSavepoint().

    - Use a per-session Calendar instance by default when decoding dates
      from ServerPreparedStatements (set to old, less performant behavior by
      setting property 'dynamicCalendars=true').

    - Added experimental configuration property 'dontUnpackBinaryResults',
      which delays unpacking binary result set values until they're asked for,
      and only creates object instances for non-numerical values (it is set
      to 'false' by default). For some usecase/jvm combinations, this is
      friendlier on the garbage collector.

    - Fixed BUG#5729 - UNSIGNED BIGINT unpacked incorrectly from
      server-side prepared statement result sets.

    - Fixed BUG#6225 - ServerSidePreparedStatement allocating short-lived
      objects un-necessarily.

    - Removed un-wanted new Throwable() in ResultSet constructor due to bad
      merge (caused a new object instance that was never used for every result
      set created) - Found while profiling for BUG#6359.

    - Fixed too-early creation of StringBuffer in EscapeProcessor.escapeSQL(),
      also return String when escaping not needed (to avoid unnecssary object
      allocations). Found while profiling for BUG#6359.

    - Use null-safe-equals for key comparisons in updatable result sets.

    - Fixed BUG#6537, SUM() on Decimal with server-side prepared statement ignores
      scale if zero-padding is needed (this ends up being due to conversion to DOUBLE
      by server, which when converted to a string to parse into BigDecimal, loses all
      'padding' zeros).

    - Use DatabaseMetaData.getIdentifierQuoteString() when building DBMD

    - Use 1MB packet for sending file for LOAD DATA LOCAL INFILE if that
      is < 'max_allowed_packet' on server.

    - Fixed BUG#6399, ResultSetMetaData.getColumnDisplaySize() returns incorrect
      values for multi-byte charsets.

    - Make auto-deserialization of java.lang.Objects stored in BLOBs
      configurable via 'autoDeserialize' property (defaults to 'false').

    - Re-work Field.isOpaqueBinary() to detect 'CHAR(n) CHARACTER SET BINARY'
      to support fixed-length binary fields for ResultSet.getObject().

    - Use our own implementation of buffered input streams to get around
      blocking behavior of java.io.BufferedInputStream. Disable this with

    - Fixed BUG#6348, failing to connect to the server when one of the
      addresses for the given host name is IPV6 (which the server does
      not yet bind on). The driver now loops through _all_ IP addresses
      for a given host, and stops on the first one that accepts() a

09-04-04 - Version 3.1.4-beta

    - Fixed BUG#4510 - connector/j 3.1.3 beta does not handle integers
      correctly (caused by changes to support unsigned reads in
      Buffer.readInt() -> Buffer.readShort()).

    - Added support in DatabaseMetaData.getTables() and getTableTypes()
      for VIEWs which are now available in MySQL server version 5.0.x.

    - Fixed BUG#4642 -- ServerPreparedStatement.execute*() sometimes
      threw ArrayIndexOutOfBoundsException when unpacking field metadata.

    - Optimized integer number parsing, enable 'old' slower integer parsing
      using JDK classes via 'useFastIntParsing=false' property.

    - Added 'useOnlyServerErrorMessages' property, which causes message text
      in exceptions generated by the server to only contain the text sent by
      the server (as opposed to the SQLState's 'standard' description, followed
      by the server's error message). This property is set to 'true' by default.

    - Fixed BUG#4689 - ResultSet.wasNull() does not work for primatives if a
      previous null was returned.

    - Track packet sequence numbers if enablePacketDebug=true, and throw an
      exception if packets received out-of-order.

    - Fixed BUG#4482, ResultSet.getObject() returns wrong type for strings
      when using prepared statements.

    - Calling MysqlPooledConnection.close() twice (even though an application
      error), caused NPE. Fixed.

    - Fixed BUG#5012 -- ServerPreparedStatements dealing with return of
      DECIMAL type don't work.

    - Fixed BUG#5032 -- ResultSet.getObject() doesn't return
      type Boolean for pseudo-bit types from prepared statements on 4.1.x
      (shortcut for avoiding extra type conversion when using binary-encoded
      result sets obscurred test in getObject() for 'pseudo' bit type)

    - You can now use URLs in 'LOAD DATA LOCAL INFILE' statements, and the
      driver will use Java's built-in handlers for retreiving the data and
      sending it to the server. This feature is not enabled by default,
      you must set the 'allowUrlInLocalInfile' connection property to 'true'.

    - The driver is more strict about truncation of numerics on
      ResultSet.get*(), and will throw a SQLException when truncation is
      detected. You can disable this by setting 'jdbcCompliantTruncation' to
      false (it is enabled by default, as this functionality is required
      for JDBC compliance).

    - Added three ways to deal with all-zero datetimes when reading them from
      a ResultSet, 'exception' (the default), which throws a SQLException
      with a SQLState of 'S1009', 'convertToNull', which returns NULL instead of
      the date, and 'round', which rounds the date to the nearest closest value
      which is '0001-01-01'.

    - Fixed ServerPreparedStatement to read prepared statement metadata off
      the wire, even though it's currently a placeholder instead of using
      MysqlIO.clearInputStream() which didn't work at various times because
      data wasn't available to read from the server yet. This fixes sporadic
      errors users were having with ServerPreparedStatements throwing

    - Use com.mysql.jdbc.Message's classloader when loading resource bundle,
      should fix sporadic issues when the caller's classloader can't locate
      the resource bundle.

07-07-04 - Version 3.1.3-beta

    - Mangle output parameter names for CallableStatements so they
      will not clash with user variable names.

    - Added support for INOUT parameters in CallableStatements.

    - Fix for BUG#4119, null bitmask sent for server-side prepared
      statements was incorrect.

    - Use SQL Standard SQL states by default, unless 'useSqlStateCodes'
      property is set to 'false'.

    - Added packet debuging code (see the 'enablePacketDebug' property

    - Added constants for MySQL error numbers (publicly-accessible,
      see com.mysql.jdbc.MysqlErrorNumbers), and the ability to
      generate the mappings of vendor error codes to SQLStates
      that the driver uses (for documentation purposes).

    - Externalized more messages (on-going effort).

    - Fix for BUG#4311 - Error in retrieval of mediumint column with
      prepared statements and binary protocol.

    - Support new timezone variables in MySQL-4.1.3 when

    - Support for unsigned numerics as return types from prepared statements.
      This also causes a change in ResultSet.getObject() for the 'bigint unsigned'
      type, which used to return BigDecimal instances, it now returns instances
      of java.lang.BigInteger.

06-09-04 - Version 3.1.2-alpha

    - Fixed stored procedure parameter parsing info when size was
      specified for a parameter (i.e. char(), varchar()).

    - Enabled callable statement caching via 'cacheCallableStmts'

    - Fixed case when no output parameters specified for a
      stored procedure caused a bogus query to be issued
      to retrieve out parameters, leading to a syntax error
      from the server.

    - Fixed case when no parameters could cause a NullPointerException
      in CallableStatement.setOutputParameters().

    - Removed wrapping of exceptions in MysqlIO.changeUser().

    - Fixed sending of split packets for large queries, enabled nio
      ability to send large packets as well.

    - Added .toString() functionality to ServerPreparedStatement,
      which should help if you're trying to debug a query that is
      a prepared statement (it shows SQL as the server would process).

    - Added 'gatherPerformanceMetrics' property, along with properties
      to control when/where this info gets logged (see docs for more

    - ServerPreparedStatements weren't actually de-allocating
      server-side resources when .close() was called.

    - Added 'logSlowQueries' property, along with property
      'slowQueriesThresholdMillis' to control when a query should
      be considered 'slow'.

    - Correctly map output parameters to position given in
      prepareCall() vs. order implied during registerOutParameter() -
      fixes BUG#3146.

    - Correctly detect initial character set for servers >= 4.1.0

    - Cleaned up detection of server properties.

    - Support placeholder for parameter metadata for server >= 4.1.2

    - Fix for BUG#3539 getProcedures() does not return any procedures in
      result set

    - Fix for BUG#3540 getProcedureColumns() doesn't work with wildcards
      for procedure name

    - Fixed BUG#3520 -- DBMD.getSQLStateType() returns incorrect value.

    - Added 'connectionCollation' property to cause driver to issue
      'set collation_connection=...' query on connection init if default
      collation for given charset is not appropriate.

    - Fixed DatabaseMetaData.getProcedures() when run on MySQL-5.0.0 (output of
    'show procedure status' changed between 5.0.1 and 5.0.0.

    - Fixed BUG#3804 -- getWarnings() returns SQLWarning instead of DataTruncation

    - Don't enable server-side prepared statements for server version 5.0.0 or 5.0.1,
    as they aren't compatible with the '4.1.2+' style that the driver uses (the driver
    expects information to come back that isn't there, so it hangs).

02-14-04 - Version 3.1.1-alpha

    - Fixed bug with UpdatableResultSets not using client-side
    prepared statements.

    - Fixed character encoding issues when converting bytes to
      ASCII when MySQL doesn't provide the character set, and
      the JVM is set to a multi-byte encoding (usually affecting
      retrieval of numeric values).

    - Unpack 'unknown' data types from server prepared statements
      as Strings.

    - Implemented long data (Blobs, Clobs, InputStreams, Readers)
      for server prepared statements.

    - Implemented Statement.getWarnings() for MySQL-4.1 and newer
      (using 'SHOW WARNINGS').

    - Default result set type changed to TYPE_FORWARD_ONLY
      (JDBC compliance).

    - Centralized setting of result set type and concurrency.

    - Re-factored how connection properties are set and exposed
      as DriverPropertyInfo as well as Connection and DataSource

    - Support for NIO. Use 'useNIO=true' on platforms that support

    - Support for SAVEPOINTs (MySQL >= 4.0.14 or 4.1.1).

    - Support for mysql_change_user()...See the changeUser() method
      in com.mysql.jdbc.Connection.

    - Reduced number of methods called in average query to be more

    - Prepared Statements will be re-prepared on auto-reconnect. Any errors
      encountered are postponed until first attempt to re-execute the
      re-prepared statement.

    - Ensure that warnings are cleared before executing queries
      on prepared statements, as-per JDBC spec (now that we support

    - Support 'old' profileSql capitalization in ConnectionProperties.
      This property is deprecated, you should use 'profileSQL' if possible.

    - Optimized Buffer.readLenByteArray() to return shared empty byte array
      when length is 0.

    - Allow contents of PreparedStatement.setBlob() to be retained
      between calls to .execute*().

    - Deal with 0-length tokens in EscapeProcessor (caused by callable
      statement escape syntax).

    - Check for closed connection on delete/update/insert row operations in

    - Fix support for table aliases when checking for all primary keys in

    - Removed useFastDates connection property.

    - Correctly initialize datasource properties from JNDI Refs, including
      explicitly specified URLs.

    - DatabaseMetaData now reports supportsStoredProcedures() for
      MySQL versions >= 5.0.0

    - Fixed stack overflow in Connection.prepareCall() (bad merge).

    - Fixed IllegalAccessError to Calendar.getTimeInMillis() in DateTimeValue
      (for JDK < 1.4).

    - Fix for BUG#1673, where DatabaseMetaData.getColumns() is not
      returning correct column ordinal info for non '%' column name patterns.

    - Merged fix of datatype mapping from MySQL type 'FLOAT' to
      java.sql.Types.REAL from 3.0 branch.

    - Detect collation of column for RSMD.isCaseSensitive().

    - Fixed sending of queries > 16M.

    - Added named and indexed input/output parameter support to CallableStatement.
      MySQL-5.0.x or newer.

    - Fixed NullPointerException in ServerPreparedStatement.setTimestamp(),
      as well as year and month descrepencies in
      ServerPreparedStatement.setTimestamp(), setDate().

    - Added ability to have multiple database/JVM targets for compliance
      and regression/unit tests in build.xml.

    - Fixed NPE and year/month bad conversions when accessing some
      datetime functionality in ServerPreparedStatements and their
      resultant result sets.

    - Display where/why a connection was implicitly closed (to
      aid debugging).

    - CommunicationsException implemented, that tries to determine
      why communications was lost with a server, and displays
      possible reasons when .getMessage() is called.

    - Fixed BUG#2359, NULL values for numeric types in binary
      encoded result sets causing NullPointerExceptions.

    - Implemented Connection.prepareCall(), and DatabaseMetaData.
      getProcedures() and getProcedureColumns().

    - Reset 'long binary' parameters in ServerPreparedStatement when
      clearParameters() is called, by sending COM_RESET_STMT to the

    - Merged prepared statement caching, and .getMetaData() support
      from 3.0 branch.

    - Fixed off-by-1900 error in some cases for
      years in TimeUtil.fastDate/TimeCreate() when unpacking results
      from server-side prepared statements.

    - Fixed BUG#2502 -- charset conversion issue in getTables().

    - Implemented multiple result sets returned from a statement
      or stored procedure.

    - Fixed BUG#2606 -- Server side prepared statements not returning
      datatype 'YEAR' correctly.

    - Enabled streaming of result sets from server-side prepared

    - Fixed BUG#2623 -- Class-cast exception when using
      scrolling result sets and server-side prepared statements.

    - Merged unbuffered input code from 3.0.

    - Fixed ConnectionProperties that weren't properly exposed
      via accessors, cleaned up ConnectionProperties code.

    - Fixed BUG#2671, NULL fields not being encoded correctly in
      all cases in server side prepared statements.

    - Fixed rare buffer underflow when writing numbers into buffers
      for sending prepared statement execution requests.

    - Use DocBook version of docs for shipped versions of drivers.

02-18-03 - Version 3.1.0-alpha

    - Added 'requireSSL' property.

    - Added 'useServerPrepStmts' property (default 'false'). The
      driver will use server-side prepared statements when the
      server version supports them (4.1 and newer) when this
      property is set to 'true'. It is currently set to 'false'
      by default until all bind/fetch functionality has been
      implemented. Currently only DML prepared statements are
      implemented for 4.1 server-side prepared statements.

    - Track open Statements, close all when Connection.close()
      is called (JDBC compliance).

06-23-05 - Version 3.0.17-ga

    - Fixed BUG#5874, Timestamp/Time conversion goes in the wrong 'direction'
      when useTimeZone='true' and server timezone differs from client timezone.

    - Fixed BUG#7081, DatabaseMetaData.getIndexInfo() ignoring 'unique'

    - Support new protocol type 'MYSQL_TYPE_VARCHAR'.

    - Added 'useOldUTF8Behavoior' configuration property, which causes
      JDBC driver to act like it did with MySQL-4.0.x and earlier when
      the character encoding is 'utf-8' when connected to MySQL-4.1 or

    - Fixed BUG#7316 - Statements created from a pooled connection were
      returning physical connection instead of logical connection when
      getConnection() was called.

    - Fixed BUG#7033 - PreparedStatements don't encode Big5 (and other
      multi-byte) character sets correctly in static SQL strings.

    - Fixed BUG#6966, connections starting up failed-over (due to down master)
      never retry master.

    - Fixed BUG#7061, PreparedStatement.fixDecimalExponent() adding extra
      '+', making number unparseable by MySQL server.

    - Fixed BUG#7686, Timestamp key column data needed "_binary'" stripped for

    - Backported SQLState codes mapping from Connector/J 3.1, enable with
      'useSqlStateCodes=true' as a connection property, it defaults to
      'false' in this release, so that we don't break legacy applications (it
      defaults to 'true' starting with Connector/J 3.1).

    - Fixed BUG#7601, PreparedStatement.fixDecimalExponent() adding extra
      '+', making number unparseable by MySQL server.

    - Escape sequence {fn convert(..., type)} now supports ODBC-style types
      that are prepended by 'SQL_'.

    - Fixed duplicated code in configureClientCharset() that prevented
      useOldUTF8Behavior=true from working properly.

    - Handle streaming result sets with > 2 billion rows properly by fixing
      wraparound of row number counter.

    - Fixed BUG#7607 - MS932, SHIFT_JIS and Windows_31J not recog. as
      aliases for sjis.

    - Fixed BUG#6549 (while fixing #7607), adding 'CP943' to aliases for

    - Fixed BUG#8064, which requires hex escaping of binary data when using
      multi-byte charsets with prepared statements.

    - Fixed BUG#8812, NON_UNIQUE column from DBMD.getIndexInfo() returned
      inverted value.

    - Workaround for server BUG#9098 - default values of CURRENT_* for
      DATE/TIME/TIMESTAMP/TIMESTAMP columns can't be distinguished from
      'string' values, so UpdatableResultSet.moveToInsertRow() generates
      bad SQL for inserting default values.

    - Fixed BUG#8629 - 'EUCKR' charset is sent as 'SET NAMES euc_kr' which
      MySQL-4.1 and newer doesn't understand.

    - DatabaseMetaData.supportsSelectForUpdate() returns correct value based
      on server version.

    - Use hex escapes for PreparedStatement.setBytes() for double-byte charsets
      including 'aliases' Windows-31J, CP934, MS932.

    - Added support for the "EUC_JP_Solaris" character encoding, which maps
      to a MySQL encoding of "eucjpms" (backported from 3.1 branch). This only
      works on servers that support eucjpms, namely 5.0.3 or later.

11-15-04 - Version 3.0.16-ga

    - Re-issue character set configuration commands when re-using pooled
      connections and/or Connection.changeUser() when connected to MySQL-4.1
      or newer.

    - Fixed ResultSetMetaData.isReadOnly() to detect non-writable columns
      when connected to MySQL-4.1 or newer, based on existence of 'original'
      table and column names.

    - Fixed BUG#5664, ResultSet.updateByte() when on insert row
      throws ArrayOutOfBoundsException.

    - Fixed DatabaseMetaData.getTypes() returning incorrect (i.e. non-negative)
      scale for the 'NUMERIC' type.

    - Fixed BUG#6198, off-by-one bug in Buffer.readString(string).

    - Made TINYINT(1) -> BIT/Boolean conversion configurable via 'tinyInt1isBit'
      property (default 'true' to be JDBC compliant out of the box).

    - Only set 'character_set_results' during connection establishment if
      server version >= 4.1.1.

    - Fixed regression where useUnbufferedInput was defaulting to 'false'.

    - Fixed BUG#6231, ResultSet.getTimestamp() on a column with TIME in it

09-04-04 - Version 3.0.15-production

    - Fixed BUG#4010 - StringUtils.escapeEasternUnicodeByteStream is still
      broken for GBK

    - Fixed BUG#4334 - Failover for autoReconnect not using port #'s for any
      hosts, and not retrying all hosts. (WARN: This required a change to
      the SocketFactory connect() method signature, which is now

       public Socket connect(String host, int portNumber, Properties props)

      therefore any third-party socket factories will have to be changed
      to support this signature.

    - Logical connections created by MysqlConnectionPoolDataSource will
      now issue a rollback() when they are closed and sent back to the pool.
      If your application server/connection pool already does this for you, you
      can set the 'rollbackOnPooledClose' property to false to avoid the
      overhead of an extra rollback().

    - Removed redundant calls to checkRowPos() in ResultSet.

    - Fixed BUG#4742, 'DOUBLE' mapped twice in DBMD.getTypeInfo().

    - Added FLOSS license exemption.

    - Fixed BUG#4808, calling .close() twice on a PooledConnection causes NPE.

    - Fixed BUG#4138 and BUG#4860, DBMD.getColumns() returns incorrect JDBC
      type for unsigned columns. This affects type mappings for all numeric
      types in the RSMD.getColumnType() and RSMD.getColumnTypeNames() methods
      as well, to ensure that 'like' types from DBMD.getColumns() match up
      with what RSMD.getColumnType() and getColumnTypeNames() return.

    - 'Production' - 'GA' in naming scheme of distributions.

    - Fix for BUG#4880, RSMD.getPrecision() returning 0 for non-numeric types
      (should return max length in chars for non-binary types, max length
      in bytes for binary types). This fix also fixes mapping of
      RSMD.getColumnType() and RSMD.getColumnTypeName() for the BLOB types based
      on the length sent from the server (the server doesn't distinguish between
      TINYBLOB, BLOB, MEDIUMBLOB or LONGBLOB at the network protocol level).

    - Fixed BUG#5022 - ResultSet should release Field[] instance in .close().

    - Fixed BUG#5069 -- ResultSet.getMetaData() should not return
      incorrectly-initialized metadata if the result set has been closed, but
      should instead throw a SQLException. Also fixed for getRow() and
      getWarnings() and traversal methods by calling checkClosed() before
      operating on instance-level fields that are nullified during .close().

    - Parse new timezone variables from 4.1.x servers.

    - Use _binary introducer for PreparedStatement.setBytes() and
      set*Stream() when connected to MySQL-4.1.x or newer to avoid
      misinterpretation during character conversion.

05-28-04 - Version 3.0.14-production

    - Fixed URL parsing error

05-27-04 - Version 3.0.13-production

    - Fixed BUG#3848 - Using a MySQLDatasource without server name fails

    - Fixed BUG#3920 - "No Database Selected" when using

    - Fixed BUG#3873 - PreparedStatement.getGeneratedKeys() method returns only
    1 result for batched insertions

05-18-04 - Version 3.0.12-production

    - Add unsigned attribute to DatabaseMetaData.getColumns() output
    in the TYPE_NAME column.

    - Added 'failOverReadOnly' property, to allow end-user to configure
    state of connection (read-only/writable) when failed over.

    - Backported 'change user' and 'reset server state' functionality
      from 3.1 branch, to allow clients of MysqlConnectionPoolDataSource
      to reset server state on getConnection() on a pooled connection.

    - Don't escape SJIS/GBK/BIG5 when using MySQL-4.1 or newer.

    - Allow 'url' parameter for MysqlDataSource and MysqlConnectionPool
      DataSource so that passing of other properties is possible from
      inside appservers.

    - Map duplicate key and foreign key errors to SQLState of

    - Backport documentation tooling from 3.1 branch.

    - Return creating statement for ResultSets created by
      getGeneratedKeys() (BUG#2957)

    - Allow java.util.Date to be sent in as parameter to
      PreparedStatement.setObject(), converting it to a Timestamp
      to maintain full precision (BUG#3103).

    - Don't truncate BLOBs/CLOBs when using setBytes() and/or
      setBinary/CharacterStream() (BUG#2670).

    - Dynamically configure character set mappings for field-level
      character sets on MySQL-4.1.0 and newer using 'SHOW COLLATION'
      when connecting.

    - Map 'binary' character set to 'US-ASCII' to support DATETIME
      charset recognition for servers >= 4.1.2

    - Use 'SET character_set_results" during initialization to allow any
      charset to be returned to the driver for result sets.

    - Use charsetnr returned during connect to encode queries before
      issuing 'SET NAMES' on MySQL >= 4.1.0.

    - Add helper methods to ResultSetMetaData (getColumnCharacterEncoding()
      and getColumnCharacterSet()) to allow end-users to see what charset
      the driver thinks it should be using for the column.

    - Only set character_set_results for MySQL >= 4.1.0.

    - Fixed BUG#3511, StringUtils.escapeSJISByteStream() not covering all
      eastern double-byte charsets correctly.

    - Renamed StringUtils.escapeSJISByteStream() to more appropriate

    - Fixed BUG#3554 - Not specifying database in URL caused MalformedURL

    - Auto-convert MySQL encoding names to Java encoding names if used
      for characterEncoding property.

    - Added encoding names that are recognized on some JVMs to fix case
      where they were reverse-mapped to MySQL encoding names incorrectly.

    - Use junit.textui.TestRunner for all unit tests (to allow them to be
      run from the command line outside of Ant or Eclipse).

    - Fixed BUG#3557 - UpdatableResultSet not picking up default values
      for moveToInsertRow().

    - Fixed BUG#3570 - inconsistent reporting of column type. The server
      still doesn't return all types for *BLOBs *TEXT correctly, so the
      driver won't return those correctly.

    - Fixed BUG#3520 -- DBMD.getSQLStateType() returns incorrect value.

    - Fixed regression in PreparedStatement.setString() and eastern character

    - Made StringRegressionTest 4.1-unicode aware.

02-19-04 - Version 3.0.11-stable

    - Trigger a 'SET NAMES utf8' when encoding is forced to 'utf8' _or_
    'utf-8' via the 'characterEncoding' property. Previously, only the
    Java-style encoding name of 'utf-8' would trigger this.

    - AutoReconnect time was growing faster than exponentially (BUG#2447).

    - Fixed failover always going to last host in list (BUG#2578)

    - Added 'useUnbufferedInput' parameter, and now use it by default
      (due to JVM issue

    - Detect 'on/off' or '1','2','3' form of lower_case_table_names on

    - Return 'java.lang.Integer' for TINYINT and SMALLINT types from
      ResultSetMetaData.getColumnClassName() (fix for BUG#2852).

    - Return 'java.lang.Double' for FLOAT type from ResultSetMetaData.
      getColumnClassName() (fix for BUG#2855).

    - Return '[B' instead of java.lang.Object for BINARY, VARBINARY and
      LONGVARBINARY types from ResultSetMetaData.getColumnClassName()
      (JDBC compliance).

    - Issue connection events on all instances created from a

01-13-04 - Version 3.0.10-stable

    - Don't count quoted id's when inside a 'string' in PreparedStatement
      parsing (fix for BUG#1511).

    - 'Friendlier' exception message for PacketTooLargeException

    - Backported fix for aliased tables and UpdatableResultSets in
      checkUpdatability() method from 3.1 branch.

    - Fix for ArrayIndexOutOfBounds exception when using Statement.setMaxRows()

    - Fixed BUG#1576, dealing with large blobs and split packets not being
      read correctly.

    - Fixed regression of Statement.getGeneratedKeys() and REPLACE statements.

    - Fixed BUG#1630, subsequent call to ResultSet.updateFoo() causes NPE if
      result set is not updatable.

    - Fix for 4.1.1-style auth with no password.

    - Fix for BUG#1731, Foreign Keys column sequence is not consistent in

    - Fix for BUG#1775 - DatabaseMetaData.getSystemFunction() returning
      bad function 'VResultsSion'.

    - Fix for BUG#1592 -- cross-database updatable result sets
      are not checked for updatability correctly.

    - DatabaseMetaData.getColumns() should return Types.LONGVARCHAR for
      MySQL LONGTEXT type.

    - ResultSet.getObject() on TINYINT and SMALLINT columns should return
      Java type 'Integer' (BUG#1913)

    - Added 'alwaysClearStream' connection property, which causes the driver
      to always empty any remaining data on the input stream before
      each query.

    - Added more descriptive error message 'Server Configuration Denies
      Access to DataSource', as well as retrieval of message from server.

    - Autoreconnect code didn't set catalog upon reconnect if it had been

    - Implement ResultSet.updateClob().

    - ResultSetMetaData.isCaseSensitive() returned wrong value for CHAR/VARCHAR

    - Fix for BUG#1933 -- Connection property "maxRows" not honored.

    - Fix for BUG#1925 -- Statements being created too many times in

    - Fix for BUG#1914 -- Support escape sequence {fn convert ... }

    - Fix for BUG#1958 -- ArrayIndexOutOfBounds when parameter number ==
      number of parameters + 1.

    - Fix for BUG#2006 -- ResultSet.findColumn() should use first matching
      column name when there are duplicate column names in SELECT query

    - Removed static synchronization bottleneck from

    - Removed static synchronization bottleneck from instance factory
      method of SingleByteCharsetConverter.

    - Enable caching of the parsing stage of prepared statements via
      the 'cachePrepStmts', 'prepStmtCacheSize' and 'prepStmtCacheSqlLimit'
      properties (disabled by default).

    - Speed up parsing of PreparedStatements, try to use one-pass whenever

    - Fixed security exception when used in Applets (applets can't
      read the system property 'file.encoding' which is needed

    - Use constants for SQLStates.

    - Map charset 'ko18_ru' to 'ko18r' when connected to MySQL-4.1.0 or

    - Ensure that Buffer.writeString() saves room for the \0.

    - Fixed exception 'Unknown character set 'danish' on connect w/ JDK-1.4.0

    - Fixed mappings in SQLError to report deadlocks with SQLStates of '41000'.

    - 'maxRows' property would affect internal statements, so check it for all
      statement creation internal to the driver, and set to 0 when it is not.

10-07-03 - Version 3.0.9-stable

    - Faster date handling code in ResultSet and PreparedStatement (no longer
      uses Date methods that synchronize on static calendars).

    - Fixed test for end of buffer in Buffer.readString().

    - Fixed ResultSet.previous() behavior to move current
      position to before result set when on first row
      of result set (bugs.mysql.com BUG#496)

    - Fixed Statement and PreparedStatement issuing bogus queries
      when setMaxRows() had been used and a LIMIT clause was present
      in the query.

    - Fixed BUG#661 - refreshRow didn't work when primary key values
      contained values that needed to be escaped (they ended up being

    - Support InnoDB contraint names when extracting foreign key info
      in DatabaseMetaData BUG#517 and BUG#664
      (impl. ideas from Parwinder Sekhon)

    - Backported 4.1 protocol changes from 3.1 branch (server-side SQL
      states, new field info, larger client capability flags,
      connect-with-database, etc).

    - Fix UpdatableResultSet to return values for getXXX() when on
      insert row (BUG#675).

    - The insertRow in an UpdatableResultSet is now loaded with
      the default column values when moveToInsertRow() is called

    - DatabaseMetaData.getColumns() wasn't returning NULL for
      default values that are specified as NULL.

    - Change default statement type/concurrency to TYPE_FORWARD_ONLY
      and CONCUR_READ_ONLY (spec compliance).

    - Don't try and reset isolation level on reconnect if MySQL doesn't
      support them.

    - Don't wrap SQLExceptions in RowDataDynamic.

    - Don't change timestamp TZ twice if useTimezone==true (BUG#774)

    - Fixed regression in large split-packet handling (BUG#848).

    - Better diagnostic error messages in exceptions for 'streaming'
      result sets.

    - Issue exception on ResultSet.getXXX() on empty result set (wasn't
      caught in some cases).

    - Don't hide messages from exceptions thrown in I/O layers.

    - Don't fire connection closed events when closing pooled connections, or
      on PooledConnection.getConnection() with already open connections (BUG#884).

    - Clip +/- INF (to smallest and largest representative values for the type in
      MySQL) and NaN (to 0) for setDouble/setFloat(), and issue a warning on the
      statement when the server does not support +/- INF or NaN.

    - Fix for BUG#879, double-escaping of '\' when charset is SJIS or GBK and '\'
      appears in non-escaped input.

    - When emptying input stream of unused rows for 'streaming' result sets,
      have the current thread yield() every 100 rows in order to not monopolize
      CPU time.

    - Fixed BUG#1099, DatabaseMetaData.getColumns() getting confused about the
      keyword 'set' in character columns.

    - Fixed deadlock issue with Statement.setMaxRows().

    - Fixed CLOB.truncate(), BUG#1130

    - Optimized CLOB.setChracterStream(), BUG#1131

    - Made databaseName, portNumber and serverName optional parameters
      for MysqlDataSourceFactory (BUG#1246)

    - Fix for BUG#1247 -- ResultSet.get/setString mashing char 127

    - Backported auth. changes for 4.1.1 and newer from 3.1 branch.

    - Added com.mysql.jdbc.util.BaseBugReport to help creation of testcases
      for bug reports.

    - Added property to 'clobber' streaming results, by setting the
      'clobberStreamingResults' property to 'true' (the default is 'false').
      This will cause a 'streaming' ResultSet to be automatically
      closed, and any oustanding data still streaming from the server to
      be discarded if another query is executed before all the data has been
      read from the server.

05-23-03 - Version 3.0.8-stable

    - Allow bogus URLs in Driver.getPropertyInfo().

    - Return list of generated keys when using multi-value INSERTS
      with Statement.getGeneratedKeys().

    - Use JVM charset with filenames and 'LOAD DATA [LOCAL] INFILE'

    - Fix infinite loop with Connection.cleanup().

    - Changed Ant target 'compile-core' to 'compile-driver', and
      made testsuite compilation a separate target.

    - Fixed result set not getting set for Statement.executeUpdate(),
      which affected getGeneratedKeys() and getUpdateCount() in
      some cases.

    - Unicode character 0xFFFF in a string would cause the driver to
      throw an ArrayOutOfBoundsException (Bug #378)

    - Return correct amount of generated keys when using 'REPLACE'

    - Fix problem detecting server character set in some cases.

    - Fix row data decoding error when using _very_ large packets.

    - Optimized row data decoding.

    - Issue exception when operating on an already-closed
      prepared statement.

    - Fixed SJIS encoding bug, thanks to Naoto Sato.

    - Optimized usage of EscapeProcessor.

    - Allow multiple calls to Statement.close()

04-08-03 - Version 3.0.7-stable

    - Fixed MysqlPooledConnection.close() calling wrong event type.

    - Fixed StringIndexOutOfBoundsException in PreparedStatement.

    - 4.1 Column Metadata fixes

    - Remove synchronization from Driver.connect() and

    - IOExceptions during a transaction now cause the Connection to
      be closed.

    - Fixed missing conversion for 'YEAR' type in ResultSetMetaData.

    - Don't pick up indexes that start with 'pri' as primary keys
      for DBMD.getPrimaryKeys().

    - Throw SQLExceptions when trying to do operations on a forcefully
      closed Connection (i.e. when a communication link failure occurs).

    - You can now toggle profiling on/off using

    - Fixed charset issues with database metadata (charset was not
      getting set correctly).

    - Updatable ResultSets can now be created for aliased tables/columns
      when connected to MySQL-4.1 or newer.

    - Fixed 'LOAD DATA LOCAL INFILE' bug when file > max_allowed_packet.

    - Fixed escaping of 0x5c ('\') character for GBK and Big5 charsets.

    - Fixed ResultSet.getTimestamp() when underlying field is of type DATE.

    - Ensure that packet size from alignPacketSize() does not
      exceed MAX_ALLOWED_PACKET (JVM bug)

    - Don't reset Connection.isReadOnly() when autoReconnecting.

02-18-03 - Version 3.0.6-stable

    - Fixed ResultSetMetaData to return "" when catalog not known.
      Fixes NullPointerExceptions with Sun's CachedRowSet.

    - Fixed DBMD.getTypeInfo() and DBMD.getColumns() returning
      different value for precision in TEXT/BLOB types.

    - Allow ignoring of warning for 'non transactional tables' during
      rollback (compliance/usability) by setting 'ignoreNonTxTables'
      property to 'true'.

    - Fixed SQLExceptions getting swallowed on initial connect.

    - Fixed Statement.setMaxRows() to stop sending 'LIMIT' type queries
      when not needed (performance)

    - Clean up Statement query/method mismatch tests (i.e. INSERT not
      allowed with .executeQuery()).

    - More checks added in ResultSet traversal method to catch
      when in closed state.

    - Fixed ResultSetMetaData.isWritable() to return correct value.

    - Add 'window' of different NULL sorting behavior to
      DBMD.nullsAreSortedAtStart (4.0.2 to 4.0.10, true, otherwise,

    - Implemented Blob.setBytes(). You still need to pass the
      resultant Blob back into an updatable ResultSet or
      PreparedStatement to persist the changes, as MySQL does
      not support 'locators'.

    - Backported 4.1 charset field info changes from Connector/J 3.1

01-22-03 - Version 3.0.5-gamma

    - Fixed Buffer.fastSkipLenString() causing ArrayIndexOutOfBounds
      exceptions with some queries when unpacking fields.

    - Implemented an empty TypeMap for Connection.getTypeMap() so that
      some third-party apps work with MySQL (IBM WebSphere 5.0 Connection

    - Added missing LONGTEXT type to DBMD.getColumns().

    - Retrieve TX_ISOLATION from database for
      Connection.getTransactionIsolation() when the MySQL version
      supports it, instead of an instance variable.

    - Quote table names in DatabaseMetaData.getColumns(),
      getPrimaryKeys(), getIndexInfo(), getBestRowIdentifier()

    - Greatly reduce memory required for setBinaryStream() in

    - Fixed ResultSet.isBeforeFirst() for empty result sets.

    - Added update options for foreign key metadata.

01-06-03 - Version 3.0.4-gamma

    - Added quoted identifiers to database names for

    - Added support for quoted identifiers in PreparedStatement

    - Streamlined character conversion and byte[] handling in
      PreparedStatements for setByte().

    - Reduce memory footprint of PreparedStatements by sharing
      outbound packet with MysqlIO.

    - Added 'strictUpdates' property to allow control of amount
      of checking for 'correctness' of updatable result sets. Set this
      to 'false' if you want faster updatable result sets and you know
      that you create them from SELECTs on tables with primary keys and
      that you have selected all primary keys in your query.

    - Added support for 4.0.8-style large packets.

    - Fixed PreparedStatement.executeBatch() parameter overwriting.

12-17-02 - Version 3.0.3-dev

    - Changed charsToByte in SingleByteCharConverter to be non-static

    - Changed SingleByteCharConverter to use lazy initialization of each

    - Fixed charset handling in Fields.java

    - Implemented Connection.nativeSQL()

    - More robust escape tokenizer -- recognize '--' comments, and allow
      nested escape sequences (see testsuite.EscapeProcessingTest)

    - DBMD.getImported/ExportedKeys() now handles multiple foreign keys
      per table.

    - Fixed ResultSetMetaData.getPrecision() returning incorrect values
      for some floating point types.

    - Fixed ResultSetMetaData.getColumnTypeName() returning BLOB for
      TEXT and TEXT for BLOB types.

    - Fixed Buffer.isLastDataPacket() for 4.1 and newer servers.

    - Added CLIENT_LONG_FLAG to be able to get more column flags
      (isAutoIncrement() being the most important)

    - Because of above, implemented ResultSetMetaData.isAutoIncrement()
      to use Field.isAutoIncrement().

    - Honor 'lower_case_table_names' when enabled in the server when
      doing table name comparisons in DatabaseMetaData methods.

    - Some MySQL-4.1 protocol support (extended field info from selects)

    - Use non-aliased table/column names and database names to fullly
      qualify tables and columns in UpdatableResultSet (requires
      MySQL-4.1 or newer)

    - Allow user to alter behavior of Statement/
      PreparedStatement.executeBatch() via 'continueBatchOnError' property
      (defaults to 'true').

    - Check for connection closed in more Connection methods
      (createStatement, prepareStatement, setTransactionIsolation,

    - More robust implementation of updatable result sets. Checks that
      _all_ primary keys of the table have been selected.

    - 'LOAD DATA LOCAL INFILE ...' now works, if your server is configured
      to allow it. Can be turned off with the 'allowLoadLocalInfile'
      property (see the README).

    - Substitute '?' for unknown character conversions in single-byte
      character sets instead of '\0'.

    - NamedPipeSocketFactory now works (only intended for Windows), see
      README for instructions.

11-08-02 - Version 3.0.2-dev

    - Fixed issue with updatable result sets and PreparedStatements not

    - Fixed ResultSet.setFetchDirection(FETCH_UNKNOWN)

    - Fixed issue when calling Statement.setFetchSize() when using
      arbitrary values

    - Fixed incorrect conversion in ResultSet.getLong()

    - Implemented ResultSet.updateBlob().

    - Removed duplicate code from UpdatableResultSet (it can be inherited
      from ResultSet, the extra code for each method to handle updatability
      I thought might someday be necessary has not been needed).

    - Fixed "UnsupportedEncodingException" thrown when "forcing" a
      character encoding via properties.

    - Fixed various non-ASCII character encoding issues.

    - Added driver property 'useHostsInPrivileges'. Defaults to true.
      Affects whether or not '@hostname' will be used in

    - All DBMD result set columns describing schemas now return NULL
      to be more compliant with the behavior of other JDBC drivers
      for other databases (MySQL does not support schemas).

    - Added SSL support. See README for information on how to use it.

    - Properly restore connection properties when autoReconnecting
      or failing-over, including autoCommit state, and isolation level.

    - Use 'SHOW CREATE TABLE' when possible for determining foreign key
      information for DatabaseMetaData...also allows cascade options for
      DELETE information to be returned

    - Escape 0x5c character in strings for the SJIS charset.

    - Fixed start position off-by-1 error in Clob.getSubString()

    - Implemented Clob.truncate()

    - Implemented Clob.setString()

    - Implemented Clob.setAsciiStream()

    - Implemented Clob.setCharacterStream()

    - Added com.mysql.jdbc.MiniAdmin class, which allows you to send
      'shutdown' command to MySQL server...Intended to be used when 'embedding'
      Java and MySQL server together in an end-user application.

    - Added 'connectTimeout' parameter that allows users of JDK-1.4 and newer
      to specify a maxium time to wait to establish a connection.

    - Failover and autoReconnect only work when the connection is in a
      autoCommit(false) state, in order to stay transaction safe

    - Added 'queriesBeforeRetryMaster' property that specifies how many
      queries to issue when failed over before attempting to reconnect
      to the master (defaults to 50)

    - Fixed DBMD.supportsResultSetConcurrency() so that it returns true

    - Fixed ResultSet.isLast() for empty result sets (should return false).

    - PreparedStatement now honors stream lengths in setBinary/Ascii/Character
      Stream() unless you set the connection property
      'useStreamLengthsInPrepStmts' to 'false'.

    - Removed some not-needed temporary object creation by using Strings
      smarter in EscapeProcessor, Connection and DatabaseMetaData classes.

09-21-02 - Version 3.0.1-dev

    - Fixed ResultSet.getRow() off-by-one bug.

    - Fixed RowDataStatic.getAt() off-by-one bug.

    - Added limited Clob functionality (ResultSet.getClob(),

    - Added socketTimeout parameter to URL.

    - Connection.isClosed() no longer "pings" the server.

    - Connection.close() issues rollback() when getAutoCommit() == false

    - Added "paranoid" parameter...sanitizes error messages removing
      "sensitive" information from them (i.e. hostnames, ports,
      usernames, etc.), as well as clearing "sensitive" data structures
      when possible.

    - Fixed ResultSetMetaData.isSigned() for TINYINT and BIGINT.

    - Charsets now automatically detected. Optimized code for single-byte
      character set conversion.

    - Implemented ResultSet.getCharacterStream()

    - Added "LOCAL TEMPORARY" to table types in DatabaseMetaData.getTableTypes()

    - Massive code clean-up to follow Java coding conventions (the time had come)

07-31-02 - Version 3.0.0-dev

    - !!! LICENSE CHANGE !!! The driver is now GPL. If you need
      non-GPL licenses, please contact me <mark@mysql.com>

    - JDBC-3.0 functionality including
      Statement/PreparedStatement.getGeneratedKeys() and

    - Performance enchancements - driver is now 50-100% faster
      in most situations, and creates fewer temporary objects

    - Repackaging...new driver name is "com.mysql.jdbc.Driver",
      old name still works, though (the driver is now provided
      by MySQL-AB)

    - Better checking for closed connections in Statement
      and PreparedStatement.

    - Support for streaming (row-by-row) result sets (see README)
      Thanks to Doron.

    - Support for large packets (new addition to MySQL-4.0 protocol),
      see README for more information.

    - JDBC Compliance -- Passes all tests besides stored procedure tests

    - Fix and sort primary key names in DBMetaData (SF bugs 582086 and 582086)

    - Float types now reported as java.sql.Types.FLOAT (SF bug 579573)

    - ResultSet.getTimestamp() now works for DATE types (SF bug 559134)

    - ResultSet.getDate/Time/Timestamp now recognizes all forms of invalid
      values that have been set to all zeroes by MySQL (SF bug 586058)

    - Testsuite now uses Junit (which you can get from www.junit.org)

    - The driver now only works with JDK-1.2 or newer.

    - Added multi-host failover support (see README)

    - General source-code cleanup.

    - Overall speed improvements via controlling transient object
      creation in MysqlIO class when reading packets

    - Performance improvements in  string handling and field
      metadata creation (lazily instantiated) contributed by
      Alex Twisleton-Wykeham-Fiennes

05-16-02 - Version 2.0.14

    - More code cleanup

    - PreparedStatement now releases resources on .close() (SF bug 553268)

    - Quoted identifiers not used if server version does not support them. Also,
      if server started with --ansi or --sql-mode=ANSI_QUOTES then '"' will be
      used as an identifier quote, otherwise '`' will be used.

    - ResultSet.getDouble() now uses code built into JDK to be more precise (but slower)

    - LogicalHandle.isClosed() calls through to physical connection

    - Added SQL profiling (to STDERR). Set "profileSql=true" in your JDBC url.
      See README for more information.

    - Fixed typo for relaxAutoCommit parameter.

04-24-02 - Version 2.0.13

    - More code cleanup.

    - Fixed unicode chars being read incorrectly (SF bug 541088)

    - Faster blob escaping for PrepStmt

    - Added set/getPortNumber() to DataSource(s) (SF bug 548167)

    - Added setURL() to MySQLXADataSource (SF bug 546019)

    - PreparedStatement.toString() fixed (SF bug 534026)

    - ResultSetMetaData.getColumnClassName() now implemented

    - Rudimentary version of Statement.getGeneratedKeys() from JDBC-3.0
      now implemented (you need to be using JDK-1.4 for this to work, I

    - DBMetaData.getIndexInfo() - bad PAGES fixed (SF BUG 542201)

04-07-02 - Version 2.0.12

    - General code cleanup.

    - Added getIdleFor() method to Connection and MysqlLogicalHandle.

    - Relaxed synchronization in all classes, should fix 520615 and 520393.

    - Added getTable/ColumnPrivileges() to DBMD (fixes 484502).

    - Added new types to getTypeInfo(), fixed existing types thanks to
      Al Davis and Kid Kalanon.

    - Added support for BIT types (51870) to PreparedStatement.

    - Fixed getRow() bug (527165) in ResultSet

    - Fixes for ResultSet updatability in PreparedStatement.
    - Fixed timezone off by 1-hour bug in PreparedStatement (538286, 528785).

    - ResultSet: Fixed updatability (values being set to null
      if not updated).

    - DataSources - fixed setUrl bug (511614, 525565),
      wrong datasource class name (532816, 528767)

    - Added identifier quoting to all DatabaseMetaData methods
      that need them (should fix 518108)

    - Added support for YEAR type (533556)

    - ResultSet.insertRow() should now detect auto_increment fields
      in most cases and use that value in the new row. This detection
      will not work in multi-valued keys, however, due to the fact that
      the MySQL protocol does not return this information.

    - ResultSet.refreshRow() implemented.

    - Fixed testsuite.Traversal afterLast() bug, thanks to Igor Lastric.

01-27-02 - Version 2.0.11

    - Fixed missing DELETE_RULE value in
      DBMD.getImported/ExportedKeys() and getCrossReference().

    - Full synchronization of Statement.java.

    - More changes to fix "Unexpected end of input stream"
      errors when reading BLOBs. This should be the last fix.

01-24-02 - Version 2.0.10

     - Fixed spurious "Unexpected end of input stream" errors in
       MysqlIO (bug 507456).

     - Fixed null-pointer-exceptions when using
       MysqlConnectionPoolDataSource with Websphere 4 (bug 505839).

01-13-02 - Version 2.0.9

     - Ant build was corrupting included jar files, fixed
       (bug 487669).

     - Fixed extra memory allocation in MysqlIO.readPacket()
       (bug 488663).

     - Implementation of DatabaseMetaData.getExported/ImportedKeys() and

     - Full synchronization on methods modifying instance and class-shared
       references, driver should be entirely thread-safe now (please
       let me know if you have problems)

     - DataSource implementations moved to org.gjt.mm.mysql.jdbc2.optional
       package, and (initial) implementations of PooledConnectionDataSource
       and XADataSource are in place (thanks to Todd Wolff for the
       implementation and testing of PooledConnectionDataSource with
       IBM WebSphere 4).

     - Added detection of network connection being closed when reading packets
       (thanks to Todd Lizambri).

     - Fixed quoting error with escape processor (bug 486265).

     - Report batch update support through DatabaseMetaData (bug 495101).

     - Fixed off-by-one-hour error in PreparedStatement.setTimestamp()
       (bug 491577).

     - Removed concatenation support from driver (the '||' operator),
       as older versions of VisualAge seem to be the only thing that
       use it, and it conflicts with the logical '||' operator. You will
       need to start mysqld with the "--ansi" flag to use the '||'
       operator as concatenation (bug 491680)

     - Fixed casting bug in PreparedStatement (bug 488663).

11-25-01 - Version 2.0.8

     - Batch updates now supported (thanks to some inspiration
       from Daniel Rall).

     - XADataSource/ConnectionPoolDataSource code (experimental)

     - PreparedStatement.setAnyNumericType() now handles positive
       exponents correctly (adds "+" so MySQL can understand it).

     - DatabaseMetaData.getPrimaryKeys() and getBestRowIdentifier()
       are now more robust in identifying primary keys (matches
       regardless of case or abbreviation/full spelling of Primary Key
       in Key_type column).

10-24-01 - Version 2.0.7

     - PreparedStatement.setCharacterStream() now implemented

     - Fixed dangling socket problem when in high availability
       (autoReconnect=true) mode, and finalizer for Connection will
       close any dangling sockets on GC.

     - Fixed ResultSetMetaData.getPrecision() returning one
       less than actual on newer versions of MySQL.

     - ResultSet.getBlob() now returns null if column value
       was null.

     - Character sets read from database if useUnicode=true
       and characterEncoding is not set. (thanks to
       Dmitry Vereshchagin)

     - Initial transaction isolation level read from
       database (if avaialable) (thanks to Dmitry Vereshchagin)

     - Fixed DatabaseMetaData.supportsTransactions(), and
       supportsTransactionIsolationLevel() and getTypeInfo()
       SQL_DATETIME_SUB and SQL_DATA_TYPE fields not being

     - Fixed PreparedStatement generating SQL that would end
       up with syntax errors for some queries.

     - Fixed ResultSet.isAfterLast() always returning false.

     - Fixed timezone issue in PreparedStatement.setTimestamp()
       (thanks to Erik Olofsson)

     - Captialize type names when "captializeTypeNames=true"
       is passed in URL or properties (for WebObjects, thanks
       to Anjo Krank)

     - Updatable result sets now correctly handle NULL
       values in fields.

     - PreparedStatement.setDouble() now uses full-precision
       doubles (reverting a fix made earlier to truncate them).

     - PreparedStatement.setBoolean() will use 1/0 for values
       if your MySQL Version >= 3.21.23.

06-16-01 - Version 2.0.6

     - Fixed PreparedStatement parameter checking

     - Fixed case-sensitive column names in ResultSet.java

06-13-01 - Version 2.0.5

     - Fixed ResultSet.getBlob() ArrayIndex out-of-bounds

     - Fixed ResultSetMetaData.getColumnTypeName for TEXT/BLOB

     - Fixed ArrayIndexOutOfBounds when sending large BLOB queries
       (Max size packet was not being set)

     - Added ISOLATION level support to Connection.setIsolationLevel()

     - Fixed NPE on PreparedStatement.executeUpdate() when all columns
       have not been set.

     - Fixed data parsing of TIMESTAMPs with 2-digit years

     - Added Byte to PreparedStatement.setObject()

     - ResultSet.getBoolean() now recognizes '-1' as 'true'

     - ResultSet has +/-Inf/inf support

     - ResultSet.insertRow() works now, even if not all columns are
       set (they will be set to "NULL")

     - DataBaseMetaData.getCrossReference() no longer ArrayIndexOOB

     - getObject() on ResultSet correctly does TINYINT->Byte and

12-03-00 - Version 2.0.3

     - Implemented getBigDecimal() without scale component
       for JDBC2.

     - Fixed composite key problem with updateable result sets.

     - Added detection of -/+INF for doubles.

     - Faster ASCII string operations.

     - Fixed incorrect detection of MAX_ALLOWED_PACKET, so sending
       large blobs should work now.

     - Fixed off-by-one error in java.sql.Blob implementation code.

     - Added "ultraDevHack" URL parameter, set to "true" to allow
       (broken) Macromedia UltraDev to use the driver.

04-06-00 - Version 2.0.1

     - Fixed RSMD.isWritable() returning wrong value.
       Thanks to Moritz Maass.

     - Cleaned up exception handling when driver connects

     - Columns that are of type TEXT now return as Strings
       when you use getObject()

     - DatabaseMetaData.getPrimaryKeys() now works correctly wrt
       to key_seq. Thanks to Brian Slesinsky.

     - No escape processing is done on PreparedStatements anymore
       per JDBC spec.

     - Fixed many JDBC-2.0 traversal, positioning bugs, especially
       wrt to empty result sets. Thanks to Ron Smits, Nick Brook,
       Cessar Garcia and Carlos Martinez.

     - Fixed some issues with updatability support in ResultSet when
       using multiple primary keys.

02-21-00 - Version 2.0pre5

     - Fixed Bad Handshake problem.

01-10-00 - Version 2.0pre4

     - Fixes to ResultSet for insertRow() - Thanks to
       Cesar Garcia

     - Fix to Driver to recognize JDBC-2.0 by loading a JDBC-2.0
       class, instead of relying on JDK version numbers. Thanks
       to John Baker.

     - Fixed ResultSet to return correct row numbers

     - Statement.getUpdateCount() now returns rows matched,
       instead of rows actually updated, which is more SQL-92


     - Statement/PreparedStatement.getMoreResults() bug fixed.
       Thanks to Noel J. Bergman.

     - Added Short as a type to PreparedStatement.setObject().
       Thanks to Jeff Crowder

     - Driver now automagically configures maximum/preferred packet
       sizes by querying server.

     - Autoreconnect code uses fast ping command if server supports

     - Fixed various bugs wrt. to packet sizing when reading from
       the server and when alloc'ing to write to the server.

08-17-99 - Version 2.0pre

     - Now compiles under JDK-1.2. The driver supports both JDK-1.1
       and JDK-1.2 at the same time through a core set of classes.
       The driver will load the appropriate interface classes at
       runtime by figuring out which JVM version you are using.

     - Fixes for result sets with all nulls in the first row.
       (Pointed out by Tim Endres)

     - Fixes to column numbers in SQLExceptions in ResultSet
       (Thanks to Blas Rodriguez Somoza)

     - The database no longer needs to specified to connect.
       (Thanks to Christian Motschke)

07-04-99 - Version 1.2b

     - Better Documentation (in progress), in doc/mm.doc/book1.html

     - DBMD now allows null for a column name pattern (not in
       spec), which it changes to '%'.

     - DBMD now has correct types/lengths for getXXX().

     - ResultSet.getDate(), getTime(), and getTimestamp() fixes.
       (contributed by Alan Wilken)

     - EscapeProcessor now handles \{ \} and { or } inside quotes
       correctly. (thanks to Alik for some ideas on how to fix it)

     - Fixes to properties handling in Connection.
       (contributed by Juho Tikkala)

     - ResultSet.getObject() now returns null for NULL columns
       in the table, rather than bombing out.
       (thanks to Ben Grosman)

     - ResultSet.getObject() now returns Strings for types
       from MySQL that it doesn't know about. (Suggested by
       Chris Perdue)

     - Removed DataInput/Output streams, not needed, 1/2 number
       of method calls per IO operation.

     - Use default character encoding if one is not specified. This
       is a work-around for broken JVMs, because according to spec,
       EVERY JVM must support "ISO8859_1", but they don't.

     - Fixed Connection to use the platform character encoding
       instead of "ISO8859_1" if one isn't explicitly set. This
       fixes problems people were having loading the character-
       converter classes that didn't always exist (JVM bug).
       (thanks to Fritz Elfert for pointing out this problem)

     - Changed MysqlIO to re-use packets where possible to reduce
       memory usage.

     - Fixed escape-processor bugs pertaining to {} inside

04-14-99 - Version 1.2a

     - Fixed character-set support for non-Javasoft JVMs
       (thanks to many people for pointing it out)

     - Fixed ResultSet.getBoolean() to recognize 'y' & 'n'
       as well as '1' & '0' as boolean flags.
       (thanks to Tim Pizey)

     - Fixed ResultSet.getTimestamp() to give better performance.
       (thanks to Richard Swift)

     - Fixed getByte() for numeric types.
       (thanks to Ray Bellis)

     - Fixed DatabaseMetaData.getTypeInfo() for DATE type.
       (thanks to Paul Johnston)

     - Fixed EscapeProcessor for "fn" calls.
       (thanks to Piyush Shah at locomotive.org)

     - Fixed EscapeProcessor to not do extraneous work if there
       are no escape codes.
       (thanks to Ryan Gustafson)

     - Fixed Driver to parse URLs of the form "jdbc:mysql://host:port"
       (thanks to Richard Lobb)

03-24-99 - Version 1.1i

     - Fixed Timestamps for PreparedStatements

     - Fixed null pointer exceptions in RSMD and RS

     - Re-compiled with jikes for valid class files (thanks ms!)

03-08-99 - Version 1.1h

     - Fixed escape processor to deal with un-matched { and }
       (thanks to Craig Coles)

     - Fixed escape processor to create more portable (between
       DATETIME and TIMESTAMP types) representations so that
       it will work with BETWEEN clauses.
       (thanks to Craig Longman)

     - MysqlIO.quit() now closes the socket connection. Before,
       after many failed connections some OS's would run out
       of file descriptors. (thanks to Michael Brinkman)

     - Fixed NullPointerException in Driver.getPropertyInfo.
       (thanks to Dave Potts)

     - Fixes to MysqlDefs to allow all *text fields to be
       retrieved as Strings.
       (thanks to Chris at Leverage)

     - Fixed setDouble in PreparedStatement for large numbers
       to avoid sending scientific notation to the database.
       (thanks to J.S. Ferguson)

     - Fixed getScale() and getPrecision() in RSMD.
       (contrib'd by James Klicman)

     - Fixed getObject() when field was DECIMAL or NUMERIC
       (thanks to Bert Hobbs)

     - DBMD.getTables() bombed when passed a null table-name
       pattern. Fixed. (thanks to Richard Lobb)

     - Added check for "client not authorized" errors during
       connect. (thanks to Hannes Wallnoefer)

02-19-99 - Version 1.1g

     - Result set rows are now byte arrays. Blobs and Unicode
       work bidriectonally now. The useUnicode and encoding
       options are implemented now.

     - Fixes to PreparedStatement to send binary set by
       setXXXStream to be sent un-touched to the MySQL server.

     - Fixes to getDriverPropertyInfo().

12-31-98 - Version 1.1f

     - Changed all ResultSet fields to Strings, this should allow
       Unicode to work, but your JVM must be able to convert
       between the character sets. This should also make reading
       data from the server be a bit quicker, because there is now
       no conversion from StringBuffer to String.

     - Changed PreparedStatement.streamToString() to be more
       efficient (code from Uwe Schaefer).

     - URL parsing is more robust (throws SQL exceptions on errors
       rather than NullPointerExceptions)

     - PreparedStatement now can convert Strings to Time/Date values
       via setObject() (code from Robert Currey).

     - IO no longer hangs in Buffer.readInt(), that bug was
       introduced in 1.1d when changing to all byte-arrays for
       result sets. (Pointed out by Samo Login)

11-03-98 - Version 1.1b

     - Fixes to DatabaseMetaData to allow both IBM VA and J-Builder
       to work. Let me know how it goes. (thanks to Jac Kersing)

     - Fix to ResultSet.getBoolean() for NULL strings
       (thanks to Barry Lagerweij)

     - Beginning of code cleanup, and formatting. Getting ready
       to branch this off to a parallel JDBC-2.0 source tree.

     - Added "final" modifier to critical sections in MysqlIO and
       Buffer to allow compiler to inline methods for speed.


     - If object references passed to setXXX() in PreparedStatement are
       null, setNull() is automatically called for you. (Thanks for the
       suggestion goes to Erik Ostrom)

     - setObject() in PreparedStatement will now attempt to write a
       serialized  representation of the object to the database for
       objects of Types.OTHER and objects of unknown type.

     - Util now has a static method readObject() which given a ResultSet
       and a column index will re-instantiate an object serialized in
       the above manner.

9-02-98 - Vesion 1.1

     - Got rid of "ugly hack" in MysqlIO.nextRow(). Rather than
       catch an exception, Buffer.isLastDataPacket() was fixed.

     - Connection.getCatalog() and Connection.setCatalog()
       should work now.

     - Statement.setMaxRows() works, as well as setting
       by property maxRows. Statement.setMaxRows() overrides
       maxRows set via properties or url parameters.

     - Automatic re-connection is available. Because it has
       to "ping" the database before each query, it is
       turned off by default. To use it, pass in "autoReconnect=true"
       in the connection URL. You may also change the number of
       reconnect tries, and the initial timeout value via
       "maxReconnects=n" (default 3) and "initialTimeout=n"
       (seconds, default 2) parameters. The timeout is an
       exponential backoff type of timeout, e.g. if you have initial
       timeout of 2 seconds, and maxReconnects of 3, then the driver
       will timeout 2 seconds, 4 seconds, then 16 seconds between each
       re-connection attempt.

8-24-98 - Version 1.0

     - Fixed handling of blob data in Buffer.java

     - Fixed bug with authentication packet being
       sized too small.

     - The JDBC Driver is now under the LPGL

8-14-98 -

     - Fixed Buffer.readLenString() to correctly
          read data for BLOBS.

     - Fixed PreparedStatement.stringToStream to
          correctly read data for BLOBS.

     - Fixed PreparedStatement.setDate() to not
       add a day.
       (above fixes thanks to Vincent Partington)

     - Added URL parameter parsing (?user=... etc).

8-04-98 - Version 0.9d

     - Big news! New package name. Tim Endres from ICE
       Engineering is starting a new source tree for
       GNU GPL'd Java software. He's graciously given
       me the org.gjt.mm package directory to use, so now
       the driver is in the org.gjt.mm.mysql package scheme.
       I'm "legal" now. Look for more information on Tim's
       project soon.

     - Now using dynamically sized packets to reduce
       memory usage when sending commands to the DB.

     - Small fixes to getTypeInfo() for parameters, etc.

     - DatabaseMetaData is now fully implemented. Let me
       know if these drivers work with the various IDEs
       out there. I've heard that they're working with
       JBuilder right now.

     - Added JavaDoc documentation to the package.

     - Package now available in .zip or .tar.gz.

7-28-98 - Version 0.9

     - Implemented getTypeInfo().
       Connection.rollback() now throws an SQLException
       per the JDBC spec.

     - Added PreparedStatement that supports all JDBC API
       methods for PreparedStatement including InputStreams.
       Please check this out and let me know if anything is

     - Fixed a bug in ResultSet that would break some
       queries that only returned 1 row.

     - Fixed bugs in DatabaseMetaData.getTables(),
       DatabaseMetaData.getColumns() and

     - Added functionality to Statement that allows
       executeUpdate() to store values for IDs that are
       automatically generated for AUTO_INCREMENT fields.
       Basically, after an executeUpdate(), look at the
       SQLWarnings for warnings like "LAST_INSERTED_ID =
       'some number', COMMAND = 'your SQL query'".

       If you are using AUTO_INCREMENT fields in your
       tables and are executing a lot of executeUpdate()s
       on one Statement, be sure to clearWarnings() every
       so often to save memory.

7-06-98 - Version 0.8

     - Split MysqlIO and Buffer to separate classes. Some
       ClassLoaders gave an IllegalAccess error for some
       fields in those two classes. Now mm.mysql works in
       applets and all classloaders.

       Thanks to Joe Ennis <jce@mail.boone.com> for pointing
       out the problem and working on a fix with me.

7-01-98 - Version 0.7

     - Fixed DatabaseMetadata problems in getColumns() and
       bug in switch statement in the Field constructor.

       Thanks to Costin Manolache <costin@tdiinc.com> for
       pointing these out.

5-21-98 - Version 0.6

     - Incorporated efficiency changes from
       Richard Swift <Richard.Swift@kanatek.ca> in
       MysqlIO.java and ResultSet.java

     - We're now 15% faster than gwe's driver.

     - Started working on DatabaseMetaData.

       The following methods are implemented:
        * getTables()
        * getTableTypes()
        * getColumns
        * getCatalogs()