THE WORLD DISCUSSES #PYTHIAN ON TWITTER. HAVE A QUESTION? USE OUR HASHTAG AND ASK AWAY.

Silent MyISAM Table Definition Changes and mysqldump

The other day while trying to move a schema from one MySQL server to another, I encountered a very odd issue. The schema to be moved contained both MyISAM and InnoDB tables, so the only option I had was to dump the schema using mysqldump on the source server and import it on the destination server. The dump on the source server went fine with absolutely no issues but it failed to import into the second server, and the error message was:

Can't create/write to file ‘/disk1/activity.MYI’ (Errcode: 2)

Read the rest of this entry . . .

Beware of starting slaves from the position in the master.info file

I’ve seen many a good DBA make the master of starting slaves from the position in the master.info file, most recently this week, that I want to bring it to everyone’s attention. Of course I mean the underlying issue and not the names of the DBA because that would be cruel. Read the rest of this entry . . .

When the ALTER TABLE privilege is not enough to run ALTER TABLE

I recently granted ALTER access in MySQL so a user could run the ALTER TABLE command . However after I granted the necessary privileges, the user was still not able to perform the tasks needed. Reproducing the issue using a test instance, I granted a test user the required privileges and MySQL reported no errors or warnings when the ALTER TABLE was run:
Read the rest of this entry . . .

GPL/ASL/BSD License Misconceptions and MySQL

Having been a free software user and supporter for many years, I am disheartened by some of the comments made in the MySQL/Oracle debate regarding the GNU Public License (GPL) and other licenses. There is much throwing around of misconceptions and untruths about licenses and their differences. In this blog, I shall take on some of the bigger misconceptions.

While Linux is indeed distributed under the GPL, as is MySQL, Linux has an exception that allows anyone to run any kind of applications (including closed source applications) on top of Linux.

Monty says: Help keep the Internet free

Read the rest of this entry . . .

MySQL on Debian and Ubuntu

Debian Linux (the underlying foundation of Ubuntu) manages the startup/shutdown of MySQL quite differently from the ways I am used to. I am a long-time user of both the MySQL binary provided by Red Hat/SuSE (along with Fedora and clones like CentOS and Oracle Enterprise Linux) and the official binary from mysql.com. After the successful restore of a cold backup, I started mysqld using the Debian provided init script. The script said that mysqld failed to start up, but in reality it did start up. Similarly, stopping mysqld fails.

The output below demonstrates the outputs and the behavior seen on a Ubuntu 8.04 LTS Server: Read the rest of this entry . . .

MySQL 5.1 and InnoDB Hot Backup Gotcha

Recently while we were building a slave with a newer version of MySQL 5.1 from an InnoDB Hot backup, the following error occurred when we ran mysql_upgrade:

mysql.time_zone                                    OK
mysql.time_zone_leap_second                        OK
mysql.time_zone_name                               OK
mysql.time_zone_transition                         OK
mysql.time_zone_transition_type                    OK
mysql.user                                         OK
Running 'mysql_fix_privilege_tables'...
ERROR 13 (HY000) at line 311: Can't get stat of './mysql/general_log.CSV' (Errcode: 2)
ERROR 13 (HY000) at line 316: Can't get stat of './mysql/slow_log.CSV' (Errcode: 2)
FATAL ERROR: Upgrade failed

The problem is that in MySQL 5.1, it is possible to log the slow query log and general log to tables in the mysql schema (source: Selecting General Query and Slow Query Log Output Destinations). These tables are created by default as CSV tables for performance reasons, and are created even if MySQL is set not to log to tables.

CSV tables, however, are not copied as part of the InnoDB Hot Backup process (by the wrapper script innobackupex.pl), thus creating this error. The fix to get the slave working Read the rest of this entry . . .

InnoDB Hot Backup Utility Bug

If you are using InnoDB Hot Backup utility and the innobackup.pl wrapper script, be very careful if you are not running backups under the system mysql user. There is a bug which causes InnoDB Hot Backup to sometimes report a successful backup when it actually failed. Read the rest of this entry . . .

Start NowWith Pythian - database design, management and emergency handling capabilities...

Live Updates

pythian: RT @pythianfielding: My #ukoug2011 #Exadata IORM presentation starts in a few mins in hall 7A
more



Testimonials

  • Serge Racine

    DBA, Brookfield Energy

    We are very satisfied by the service given to us by Andre and Shakir in support of our recent data quality and reorganization initiative.... more