Stefan Rufer

Netcetera CodeCamp 10.05

stefan — 2010-05-28T16:31:21GMT+01:00

To remember:

Felipe, in memoriam

stefan — 2010-03-05T21:42:22GMT+01:00

Today, Felipe went from us. Deeply moved I am hardly capable to realize what mother nature asks us to accept.

In my eyes he was one of the most prominent open source contributors at Netcetera. But that was just his technical skill - moreover he was an enthusiastic, positive man that carried the sunshine inside him.

Lacking the proper words to describe what has happened I am trying to look forward for the bright memory of Felipe to supersede the sorrow.

Certa Fides online

stefan — 2008-10-29T21:13:28GMT+01:00

As a next domain I am happy to announce http://www.certa-fides.ch and http://www.certafides.ch to go online.

MySQL root password - more troubles

stefan — 2009-03-10T00:03:11GMT+01:00

Once again some hickups when trying to update the mysql root password on my vserver.

Prolog :-)

stefan — 2009-03-10T00:03:11GMT+01:00

First, mysql service won't restart:

[root@vs /]# service mysql stop  
Shutting down MySQL. SUCCESS! 
[root@vs confixx]# service mysql start
Starting MySQL................................... ERROR!

Trying to start with the command line shows something more:

[root@vs /]# /usr/sbin/mysqld --skip-grant-tables --basedir=/ --datadir=/var/lib/mysql --user=mysql --pid-file=/var/lib/mysql/vs.vserver.de.pid --skip-external-locking --socket=/var/lib/mysql/mysql.sock
081002 16:40:12 [ERROR] Can't start server : Bind on unix socket: Permission denied
081002 16:40:12 [ERROR] Do you already have another mysqld server running on socket: /var/lib/mysql/mysql.sock ?
081002 16:40:12 [ERROR] Aborting081002 16:40:12 [Note] /usr/sbin/mysqld: Shutdown complete

Took me a minute to find out that there's no mysql user on the system (any more?) and essential files were run with a strange uid up to now:

[root@vs /]# useradd -g mysql mysql       
[root@vs /]$ ll /var/lib/mysql/
total 1556
drwxr-xr-x   6  644 mysql     4096 Oct  2 16:46 .
drwxr-xr-x  14 root root      4096 Mar 29  2006 ..
-rw-------   1  644 mysql      455 Oct 26  2007 .bash_history
drwx------   2  644 mysql     4096 Mar 29  2006 confixx
-rw-rw----   1  644 mysql  5242880 Oct  2 16:37 ib_logfile0
-rw-rw----   1  644 mysql  5242880 Oct 26  2007 ib_logfile1
-rw-rw----   1  644 mysql 10485760 Oct  2 16:37 ibdata1
drwx------   2  644 mysql     4096 Oct 26  2007 mysql
drwx------   2  644 mysql     4096 Mar 29  2006 test
drwx------   2  644 mysql     4096 Feb  4  2008 usr_web1_1
[root@vs mysql]# chown -R mysql *
[root@vs mysql]# chown -R mysql .

Now, this looks better and even starting mysql works:

[root@vs mysql]# ll
total 1556
drwxr-xr-x   6 mysql mysql     4096 Oct  2 16:46 .
drwxr-xr-x  14 root  root      4096 Mar 29  2006 ..
-rw-------   1   644 mysql      455 Oct 26  2007 .bash_history
drwx------   2 mysql mysql     4096 Mar 29  2006 confixx
-rw-rw----   1 mysql mysql  5242880 Oct  2 16:37 ib_logfile0
-rw-rw----   1 mysql mysql  5242880 Oct 26  2007 ib_logfile1
-rw-rw----   1 mysql mysql 10485760 Oct  2 16:37 ibdata1
drwx------   2 mysql mysql     4096 Oct 26  2007 mysql
drwx------   2 mysql mysql     4096 Mar 29  2006 test
drwx------   2 mysql mysql     4096 Feb  4  2008 usr_web1_1
[root@vs mysql]# service mysql start
Starting MySQL SUCCESS!

Changing MySQL password

stefan — 2009-03-10T00:03:11GMT+01:00

Finally, the interesting part, start mysql with the --skip-grant-tables option:

[root@vs /]# service mysql stop
Shutting down MySQL. SUCCESS! 
[root@vs /]# /usr/sbin/mysqld --skip-grant-tables --basedir=/ --datadir=/var/lib/mysql --user=mysql --pid-file=/var/lib/mysql/vs.vserver.de.pid --skip-external-locking --socket=/var/lib/mysql/mysql.sock

And (in another shell) change the root password:

[root@vs /]# mysql
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 3 to server version: 4.1.22-standardType 'help;' or 'h' for help. Type 'c' to clear the buffer.
mysql> UPDATE mysql.user SET Password=PASSWORD('xxxx') WHERE User='root';
Query OK, 2 rows affected (0.02 sec)
Rows matched: 2  Changed: 2  Warnings: 0
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
mysql> exit
Bye

Restart the mysql service, and see: Login as root works again:

[root@vs /]# mysql -u root --password=xxxx
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 1 to server version: 4.1.22-standardType 'help;' or 'h' for help. Type 'c' to clear the buffer.
mysql>

DLink DIR-301

stefan — 2008-09-19T22:08:58GMT+01:00

Our old WLAN router seems to have passed out after about five years. Just shopped a new DIR-301 without knowing too much.

Internet requests were slow, slow, slow especially when sent the first time to a new URL. Only some tweaking allowed me to work reasonably fast:

Disable DHCP rely (didn't help that much)
Switch off UPnP, WAN Ping Respond, GAMING Mode, Multicast Stream

Current impression is that this helps… let's see. Didn't bother to test the last four features one-by-one as they are not important to me anyway.

And one more thing: DIR-300 can be found on DLink homepages, but not DIR-301. Hmm. What a pitty. Maybe I will watch out for a more seriously evaluated product the next time.

Jazoon08 - Continuous Database Build

stefan — 2008-06-25T00:15:00GMT+01:00

Finally, finally, the page is completed: http://www.stefanrufer.ch/dbbuild It's about time as the presentation is tomorrow at Jazoon 08 :-)

Clash Of Cultures

stefan — 2008-04-06T12:26:18GMT+01:00

In an attempt of drunken euphorism the website http://www.clash-of-cultures.ch/ was created yesterday night. Nevertheless I still consider it a good idea :-)

Oracle/Derby difference for TRANSACTION_ISOLATION_COMMITTED

stefan — 2008-03-26T02:48:15GMT+01:00

Derby and Oracle will react differently if two connections try to access data with transaction isolation level TRANSACTION_READ_COMMITTED:

TrxA start
TrxA INSERT INTO test…
TrxB start
TrxB SELECT count(*) FROM test
     => Derby blocks here, Oracle continues
TrxB commit
TrxA commit

I was just a bit puzzled that such a simple test produces different results… Or am I missing something?

The attached Java sources contain the according test code.