Now it's MySQL's turn...

Some problems encounted this afternoon, when trying to setup/test mysql capabilities on hypnos and virgil.

 

1.ERROR 2003 (HY000): Can't connect to MySQL server on 'server-name' (111)

access locally (i.e. from localhost) is fine, when trying remotely got this error. when tried with mysql++ library, got the following:

 

terminate called after throwing an instance of 'mysqlpp::ConnectionFailed'
  what():  Can't connect to MySQL server on 'hypnos' (111)

 

After some searches, it appears this is just indicate network issue, not to do with mysql authentication.

TWO most likely reasons are:

 a. with --skip-networking on it will not accept TCP/IP connections at all.

 b. with --bind-address=127.0.0.1, it will listen for TCP/IP connections only locally on the loopback interface and will not accept remote connections.

 

did find skip-networking option from mysql-workbench and it's off, not find bind-address at all from intotal maybe hundreds options, but it turned out it IS bind-address THE ARCH CRIMINAL!!!

 

solution: comments out bind-address=127.0.0.1 from /etc/mysql/my.cnf

 

 

Some other tips came across during the search

2. UFW -- The default firewall configuration tool for Ubuntu.

https://help.ubuntu.com/community/UFW

http://blog.bodhizazen.net/linux/firewall-ubuntu-gufw/
http://blog.bodhizazen.net/linux/fir...untu-desktops/
http://blog.bodhizazen.net/linux/fir...buntu-servers/

 

example: To allow/deny incoming tcp and udp packet on port 53

• sudo ufw allow/deny 53

example: To allow/deny incoming tcp packets on port 53

• sudo ufw allow/deny 53/tcp

example: To allow/deny incoming udp packes on port 53

 

sudo ufw allow/deny 53/udp

 

3. Error communicating with gnome-keyring-daemon, when initially using mysql-workbench to connect to mysql database

a good collection of threads:

http://ubuntuforums.org/showthread.php?p=9359283

 

1) gnome-keyring-daemon is a piece of software that works like a "safe password database" for other applications to use
2) other applications access it through libgnome-keyring
3) recent changes on libgnome-keyring made it unable to find gnome-keyring-daemon through "environment variables", but only through "dbus"
4) in order to dbus be able to find gnome-keyring-daemon it must be started BEFORE
5) on system start up, dbus is started AFTER gnome-keyring-daemon
6) so: no application which uses libgnome-keyring can access gnome-keyring-daemon because dbus can't see it

 

Solution: manually start:

$shell> gnome-keyring-daemon





4. Emptying mysql tables - DELETE or TRUNCATE?

http://netfactory.dk/2005/11/21/emptying-mysql-tables/

DELETE FROM tablename;

TRUNCATE tablename;

"Besides the fact that it seems to be faster (even on small tables with few rows) – which in itself is a reason to favour this method – it also has another nice feature, which may be desirable. It resets the AUTO_INCREMENT field if it exists, and let the counter start over from 1.

Deleting rows in the table with the first statement will let the AUTO_INCREMENT counter continiue from where it was before the rows were deleted."

5. OnlineMySQL Training Course

http://www.webdevelopersnotes.com/tutorials/sql/online_mysql_training_course_counting.php3