Oh yes, 2012 was an incredible year for the MySQL Community!
That’s why I would like to change the rules this year and I would like to offer you a new survey for this [Plus] reader’s choice 2012.

Community users, bloggers and events made the whole community last year, tell us how you used this community?
It will only take 5 minutes of your precious time, votes will be closed Jan. 31.

Vote for what you used! (with your heart, again…)

Note: There is a poll embedded within this post, please visit the site to participate in this post's poll. Note: There is a poll embedded within this post, please visit the site to participate in this post's poll. Note: There is a poll embedded within this post, please visit the site to participate in this post's poll. Note: There is a poll embedded within this post, please visit the site to participate in this post's poll.

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Hot backups are important for high availability, they can run without blocking the application. Percona Xtrabackup is a great tool for backing up InnoDB data. 
We have created a backup tool called s9s_backup that makes Xtrabackup really easy to use, and is fully integrated with ClusterControl, which means that you can schedule backups with ease and view the backups that you have taken, and also restore the backups with no pain.

s9s_backup is available in the lastest version of ClusterControl or you can download it here.

Is mysqldump totally useless then?

No. If you would like to isolate and load only one table, mysqldump is great, or if you want to …

In my opinion, The Server Option and Variable Reference at http://dev.mysql.com/doc/refman/5.5/en/mysqld-option-tables.html rates as my most important page. This is a consolidated index that enables a drill down to the Server Command Options, System Variables, Startup and replication specifics, as well as important information on default values and differences between versions including point releases.

However, there is another page not in the actual manual, but at http://dev.mysql.com/doc/mysqld-version-reference/en/mysqld-version-reference-optvar.html which is an Options/Variables reference akin to the Reference Manual, but includes a 5.x version matrix.

Recently I was asked about some options that had to be …

This is the title of my first blog post on MySQL Performance Blog. It deals with a customer case where the customer was facing a peculiar problem where the rows column in the EXPLAIN output of the query was totally off. The actual number of rows was 18 times more than the number of rows reported by MySQL in the output of EXPLAIN. Now this can be a real pain as MySQL uses “the number of rows” estimation to pick and choose indexes and it could really be picking up a wrong index simply because of the wrong estimate. You...

The post When EXPLAIN estimates can go wrong! appeared first on ovais.tariq.

This blog post shows how you can use the Severalnines Configurator for MySQL Replication to deploy a Multi-master replication setup, and install ClusterControl.
You can also watch videos showing what is described below or read an even more detailed tutorial.

When the deployment is finished you have a set of tools to manage and monitor replication, as well as to add new slaves, and to perform failover.
You can choose:

• The number of slaves you wish to connect to the …

To whom it may concern -

Today, I received an email from a user of the udf_init_error UDF (which resides in the lib_mysqludf_udf library). The purpose of this UDF is to generate an error condition, which can be used to abruptly terminate a trigger or stored procedure. As such it is a workaround for bug #11661. This is all described extensively in my now ancient article here.

The user wrote me because of a problem experienced in MySQL 5.5: ...calling

select …

Following up to my previous blog on graphing statement execution in performance_schema, Sunny Bains on the InnoDB team pointed out that in looking at the INSERT graph, he didn’t think I had atomic operations enabled within my build.

Particularly here (from trunk):

225 /******************************************************************//**
226 Increments lock_word the specified amount and returns new value.
227 @return lock->lock_word after increment */
228 UNIV_INLINE
229 lint
230 rw_lock_lock_word_incr(
231 /*===================*/
232         rw_lock_t*      lock,           /*!< in/out: rw-lock */
233         ulint           amount)         /*!< in: amount of increment */
234 {
235 #ifdef …

Read the detailed replication tutorial instead.


This tutorial shows how you can use the Severalnines Configurator for MySQL Replication to deploy a Multi-master replication setup, and install ClusterControl.

When the deployment is finished you have a set of tools to manage and monitor replication, as well as to add new slaves, and to perform failover.
You can choose:

• if you wish also setup bi-directional replication between the masters
• the number of …

Beginning with MySQL 5.1 as an additional plugin and included by default in MySQL 5.5 the InnoDB plugin includes many performance improvements. To leverage the support of new file formats however a very important setting is necessary.

#my.cnf
[mysqld]
innodb_file_per_table

The use of innodb_file_per_table with an existing system or during an upgrade to 5.1 or 5.5 requires a complete reload of your database to use effectively. In summary.

• Backup all InnoDB tables via mysqldump
• Drop InnoDB tables
• Verify InnoDB not used
• Stop MySQL
• Enable innodb_file_per_table & simplified innodb_data_file_path (if applicable)
• Remove ibdata? files
• Start MySQL
• Create Tables
• Reload Data
• Verify InnoDB Operation

The primary reason is we are moving from …

Today I discovered an interesting upgrade problem with a client migrating from MySQL 5.0 to 5.5. The client who is undertaking the upgrade reported that MySQL 5.5 did not support the DECIMAL(18,5) data type. I easily confirmed this not to be the case:

mysql> drop table if exists x;
mysql> create table x (col1 DECIMAL(18,5));
Query OK, 0 rows affected (0.01 sec)

Delving more into the issue in question, I looked at the complete CREATE TABLE statement, recreating the syntax.

mysql> drop table if exists x;
mysql> create table x ( MinValue DECIMAL(18,5));
Query OK, 0 rows affected (0.00 sec)

No problem there.

mysql> drop table if exists x;
mysql> create table x (Department INT NOT NULL, MinValue DECIMAL(18,5) NULL, MaxValue DECIMAL(18,5) NULL);
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near …