Introduction

Online DDL is a new feature in MariaDB 10.0. Online DDL is processed through below 4 tasks in sequence.

1. InnoDB::ha_prepare_inplace_alter_table(..)
2. InnoDB::ha_inplace_alter_table(..)
3. InnoDB::ha_commit_inplace_alter_table(..)
4. mysql_rename_table(..)

InnoDB storage engine allocates temporal memory buffer for transaction logging in phase 1 where row changes during this phase are logged. Size of this buffer is at start sort_buffer_size and it can be grown up to innodb_online_alter_log_max size. During phase 2 thread processing the ALTER statement will copy old table’s rows to a new altered table. After this MariaDB will take exclusive lock for target table and applies row log buffer to the new altered table.

This introduces a new unpredictable failure case row log buffer overflow. MariaDB server will rollback ALTER statement if row log buffer …

One of the most popular plugin types both in MariaDB and MySQL is INFORMATION_SCHEMA plugin type. INFORMATION_SCHEMA plugins add new tables to the INFORMATION_SCHEMA. There are lots of INFORMATION_SCHEMA plugins, because they can be used to show just anything to the user and are very easy to write.

MariaDB 10.1.1 comes with nine INFORMATION_SCHEMA plugin:

• Feedback — shows the anonymised server usage information and can optionally send it to the configured url.
• Locales — lists compiled-in server locales, implemented by Roberto Spadim
• METADATA_LOCK_INFO — Lists metadata locks in the server. Implemented by Kentoku Shiba
• …

Taxonomy upgrade extras: BackupRestoreRecoveryinnodbtable

Precaution: Before you try this out on your production system do a BACKUP first! FromDual Backup Manager can help you with this.

Situation

A MySQL user has delete its InnoDB table files for example like this:

shell> rm -f $datadir/test/test.*

Analysis

We do some analysis first:

mysql> DROP TABLE test;
ERROR 1051 (42S02): Unknown table 'test' …

MySQL sys version 1.2.0 has just been released.

All views now work with MySQL 5.7.5, and the ONLY_FULL_GROUP_BY changes.

There is also a new script available (generate_sql_file.sh) that will allow RDS users to easily generate a single SQL file, using a specified user, that can be loaded in to an RDS instance. See the README for details on how to use that.

Here’s a full summary of the other changes:

Backwards Incompatible Changes

• The host_summary_by_stages and user_summary_by_stages wait_sum and wait_avg columns were renamed to total_latency and avg_latency respectively, for consistency.
…

I just publish a post on the Booking.com blog: http://blog.booking.com/better_crash_safe_replication_for_mysql.html  Spoiler: it uses Binlog Servers.

This is also the opportunity to tell you that I will be at Percona Live London at the beginning of November, and that I will give a talk about Binlog Servers: High Availability, Disaster Recovery and Extreme Read Scaling using Binlog Servers.  I

So as you may know, my new position involves the MySQL world, so I’m in the task of picking up the language and whereabouts of this DBMS, and my teamate Alkin Tezuysal (@ask_dba on Twitter) has a very cool break and fix lab which you should check out if you are going to Percona Live London 2014, he will be running this lab, so be sure to don’t miss out.

So the first thing I tried was to bring up the service, but to my surprise, the MySQL user didn’t exist. So the first thing I did was create the user.

Note: Whenever you see “…”, it is to …

We have come a long way since the first code was put down for libAttachSQL on the 4th July. It has been a fantastic project to work on so I am very pleased to announce our first GA release.

For those who haven't seen it so far libAttachSQL is a non-blocking, lightweight C API for MySQL servers. It is Apache 2.0 licensed so is compatible with most Open Source and commercial licensing. HP's Advanced Technology Group saw a need in this field not just for HP itself but for other companies and projects too.

As for the GA release itself, there are not many changes over the RC release beyond stability fixes. A full list can be seen in the version history documentation.

In addition to the GA release we have recently had a driver for …

Wed, 2014-10-22 09:02svetoslavsavov

Next time you want to build a fast, well-optimized website, don't forget the database system. Many content management systems (CMS) let you choose a relational database management system (RDBMS) to use on the back end. MySQL, famous for its stability and security, is a popular choice; in addition to its numerous features, it has a large community, many contributors, and good documentation. However, MySQL is now owned by Oracle, and its open-source status is not guaranteed, which makes MariaDB, an application compatible database system, an excellent alternative.

Joomla, a popular CMS, is written in PHP and by default uses MySQL as its database system. Since MariaDB can provide improved functionality, performance, and stability, you might want to use MariaDB instead of MySQL with Joomla. Although MariaDB is not listed in …

Wed, 2014-10-22 09:02svetoslavsavov

Next time you want to build a fast, well-optimized website, don't forget the database system. Many content management systems (CMS) let you choose a relational database management system (RDBMS) to use on the back end. MySQL, famous for its stability and security, is a popular choice; in addition to its numerous features, it has a large community, many contributors, and good documentation. However, MySQL is now owned by Oracle, and its open-source status is not guaranteed, which makes MariaDB, an application compatible database system, an excellent alternative.

Joomla, a popular CMS, is written in PHP and by default uses MySQL as its database system. Since MariaDB can provide improved functionality, performance, and stability, you might want to use MariaDB instead of MySQL with Joomla. Although MariaDB is not listed in …

Every now and then there is a need to execute certain SQL statements conditionally. Easy, if you do it from your PHP (or Java or whatever) application. But if all you have is pure SQL? There are two techniques that MariaDB and MySQL use in the mysql_fix_privilege_tables.sql script (applied by mysql_upgrade tool).

1. Create a stored procedure with IF statements inside, call it once and drop it. This requires the user to have the CREATE ROUTINE privilege and mysql.proc table must exist and be usable (which is not necessarily true — we’re doing it from mysql_upgrade, right?).
2. Use dynamic SQL, like
   

   SET @str = IF (@have_csv = 'YES',
                  'CREATE TABLE IF NOT EXISTS general_log (
                     event_time TIMESTAMP(6) NOT NULL,
                     user_host MEDIUMTEXT NOT NULL,
                     thread_id BIGINT(21) UNSIGNED NOT NULL, …