Archive for April, 2012

Amateurs – They give us professionals a bad name

Thursday, April 26th, 2012

Any person with half a brain would see from the error messages below that the MySQL server is not operating optimally, or more specifically the MySQL upgrade has not completely successfully and let users can go happily use the website. It amazing me when web hosting providers tell their paying client that an upgrade has been performed yet they did not have the intelligence to actually look at the error log for confirmation. Got a mysql> prompt, it’s all good. One of the first things I check is the error log.

When will people learn the MySQL error log is a valuable resource both for what it contains, and what it should not contain.

120426 17:36:00 [Note] /usr/libexec/mysqld: Shutdown complete

120426 17:36:00 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
120426 17:36:00 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
120426 17:36:00 [Note] Plugin 'FEDERATED' is disabled.
/usr/libexec/mysqld: Table 'mysql.plugin' doesn't exist
120426 17:36:00 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
120426 17:36:00 InnoDB: The InnoDB memory heap is disabled
120426 17:36:00 InnoDB: Mutexes and rw_locks use GCC atomic builtins
120426 17:36:00 InnoDB: Compressed tables use zlib 1.2.3
120426 17:36:00 InnoDB: Using Linux native AIO
120426 17:36:00 InnoDB: Initializing buffer pool, size = 128.0M
120426 17:36:00 InnoDB: Completed initialization of buffer pool
120426 17:36:00 InnoDB: highest supported file format is Barracuda.
120426 17:36:00  InnoDB: Waiting for the background threads to start
120426 17:36:01 InnoDB: 1.1.8 started; log sequence number 232577699
120426 17:36:01 [ERROR] Missing system table mysql.proxies_priv; please run mysql_upgrade to create it
120426 17:36:01 [ERROR] Can't open and lock privilege tables: Table 'mysql.servers' doesn't exist
120426 17:36:01 [ERROR] Native table 'performance_schema'.'events_waits_current' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'events_waits_history' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'events_waits_history_long' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'setup_consumers' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'setup_instruments' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'setup_timers' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'performance_timers' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'threads' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'events_waits_summary_by_thread_by_event_name' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'events_waits_summary_by_instance' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'events_waits_summary_global_by_event_name' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'file_summary_by_event_name' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'file_summary_by_instance' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'mutex_instances' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'rwlock_instances' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'cond_instances' has the wrong structure
120426 17:36:01 [ERROR] Native table 'performance_schema'.'file_instances' has the wrong structure
120426 17:36:01 [ERROR] Column count of mysql.db is wrong. Expected 22, found 20. Created with MySQL 50077, now running 50523. Please use mysql_upgrade to fix this error.
120426 17:36:01 [ERROR] mysql.user has no `Event_priv` column at position 29
120426 17:36:01 [ERROR] Cannot open mysql.event
120426 17:36:01 [ERROR] Event Scheduler: An error occurred when initializing system tables. Disabling the Event Scheduler.
120426 17:36:01 [Note] /usr/libexec/mysqld: ready for connections.
Version: '5.5.23-cll'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  MySQL Community Server (GPL) by Atomicorp
120426 17:46:01 [ERROR] Missing system table mysql.proxies_priv; please run mysql_upgrade to create it
120426 17:46:01 [ERROR] Can't open and lock privilege tables: Table 'mysql.servers' doesn't exist
120426 17:46:01 [ERROR] Column count of mysql.proc is wrong. Expected 20, found 16. Created with MySQL 50077, now running 50523. Please use mysql_upgrade to fix this error.

Some more light reading at Have you checked your MySQL error log today? and Monitoring MySQL – The error log

I want a mysqldump –ignore-database option

Wednesday, April 18th, 2012

While working with RDS and Google Cloud SQL I have come to realize that excluding the mysql schema from a mysqldump is important. However with many databases, the –all-databases option enables you only to select all or none. There is however an easy solution to exclude one or more databases in mysqldump with this little gem I created.

$ time mysqldump --databases `mysql --skip-column-names -e "SELECT GROUP_CONCAT(schema_name SEPARATOR ' ') FROM information_schema.schemata WHERE schema_name NOT IN ('mysql','performance_schema','information_schema');" >` >/mysql/backup/rds2.sql

An you can exclude as many schemas as you want.

I checked the mysqldump –help, there was no option in MySQL 5.1, asked a colleague just to be sure I wasn’t wasting my time, and it took all of 2 minutes to create and test a working solution.

When is a database schema not a database schema?

Wednesday, April 18th, 2012
mysql> show schemas;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| innodb             |
| mysql              |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)
mysql> drop schema innodb;
ERROR 1010 (HY000): Error dropping database (can't rmdir './innodb/', errno: 17)

This is an additional schema that is included in an AWS RDS installation. You should not put directories in the MySQL data directory.

An excellent conference (5 out of 5 stars)

Saturday, April 14th, 2012

I wanted to extend thanks as others have also about the excellent annual MySQL Conference, now a Percona Live event. This was easily the best run, attended and energetic event in at least the past 3 years. With over a 1000 attendees a well stocked exhibitors hall (and good involvement in the hall), and good talks; there was just a great community vibe. To Terry, Kortney and all Percona staff involved, well done. The event ran on time, I personally did not see or hear of any issues. The only complaint was from many that wanted to attend multiple talks at the same time, another indication of the quality of speakers for the event.

Thank you to those that attended my two sessions on Explaining the MySQL Explain and MySQL Idiosyncrasies that BITE. Many people thanked me after presentations, along also with people coming up to me to say they appreciated the first book of the Effective MySQL Series. My desires to speak and write are only for the benefit of the MySQL community to hopefully learn and appreciate how to best use MySQL.

It was of course great to see many MySQL alumni, and old friends I have seen since meeting at my first MySQL conference in 2006.

MySQL now has two user conferences (*)

Thursday, April 5th, 2012

PC World has written a post with this title(*) about the upcoming MySQL Connect conference and references the Percona Live conference and an official Percona comment. As this is not syndicated in Planet MySQL I encourage you to read the full article.

This is the MySQL conference to get technical presentations by the many great Oracle/MySQL technical staff who will not be in attendance at Percona Live. There will also be a strong community presence in speaking at Oracle Connect in September. While Oracle was organizing a dedicated MySQL event in April for the community with all vendors including Percona to replace the conference dropped by long term partner O’Reilly (kudos for many years of great events), Percona decided to go at it without including Oracle, the owners and developers of MySQL. The statement quoted in the PC World article regarding “lack of momentum around the [annual community] event” is clearly inaccurate and not a true representation of actual events.

It is difficult to keep up with all the community events Oracle is now running including multiple OTN MySQL Developer days per month across the US and Europe. I will be speaking at the upcoming OTN NY event in April, the Rocky Mountain Training Day in May, and hopefully the MySQL Innovation day in June. Get the full list at Upcoming MySQL Events.

Indeed MySQL content and presentations have also been represented at Oracle Open World for a number of years. 2011 was a very large turnout and many MySQL presentations. As a senior consultant for MySQL Inc I manned a MySQL booth at OOW exhibition hall back in 2007, prior to both Sun and Oracle acquisitions.