Cannot connect to MySQL with JDBC - Connection Timeout - Ubuntu 9.04
- by gav
I am running Ubuntu and am ultimately trying to connect Tomcat to my MySQL database using JDBC.
It has worked previously but after a reboot the instance now fails to connect.
Both Tomcat 6 and MySQL 5.0.75 are on the same machine
Connection string: jdbc:mysql:///localhost:3306
I can connect to MySQL on the command line using the mysql command
The my.cnf file is pretty standard (Available on request) has bind address: 127.0.0.1
I cannot Telnet to the MySQL port despite netstat saying MySQL is listening
I have one IpTables rule to forward 80 - 8080 and no firewall I'm aware of.
I'm pretty new to this and I'm not sure what else to test. I don't know whether I should be looking in etc/interfaces and if I did what to look for. It's weird because it used to work but after a reboot it's down so I must have changed something.... :).
I realise a timeout indicates the server is not responding and I assume it's because the request isn't actually getting through. I installed MySQL via apt-get and Tomcat manually.
MySqld processes
root@88:/var/log/mysql# ps -ef | grep mysqld
root 21753 1 0 May27 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe
mysql 21792 21753 0 May27 ? 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --port=3306 --socket=/var/run/mysqld/mysqld.sock
root 21793 21753 0 May27 ? 00:00:00 logger -p daemon.err -t mysqld_safe -i -t mysqld
root 21888 13676 0 11:23 pts/1 00:00:00 grep mysqld
Netstat
root@88:/var/log/mysql# netstat -lnp | grep mysql
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 21792/mysqld
unix 2 [ ACC ] STREAM LISTENING 1926205077 21792/mysqld /var/run/mysqld/mysqld.sock
Toy Connection Class
root@88:~# cat TestConnect/TestConnection.java
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class TestConnection {
public static void main(String args[]) throws Exception {
Connection con = null;
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
System.out.println("Got driver");
con = DriverManager.getConnection(
"jdbc:mysql:///localhost:3306",
"uname", "pass");
System.out.println("Got connection");
if(!con.isClosed())
System.out.println("Successfully connected to " +
"MySQL server using TCP/IP...");
} finally {
if(con != null)
con.close();
}
}
}
Toy Connection Class Output
Note: This is the same error I get from Tomcat.
root@88:~/TestConnect# java -cp mysql-connector-java-5.1.12-bin.jar:. TestConnection
Got driver
Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 1 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1122)
at TestConnection.main(TestConnection.java:14)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1122)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:344)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2181)
... 12 more
Caused by: java.net.ConnectException: Connection timed out
at java.net.PlainSocketImpl.socketConnect(Native Method)
... 13 more
Telnet Output
root@88:~/TestConnect# telnet localhost 3306
Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection timed out
