SkySQL and MariaDB are delighted to announce that we’ll be co-hosting our first Solutions Day for the MySQL® Database on 13 April, 2012, at the Hyatt Regency Santa Clara.

During this one day event, attendees will receive free, hands-on training on MySQL database solutions from the experts at SkySQL, MariaDB, Continuent, ScaleDB, Severalnines, Sphinx, and Webyog, among others.

As well, SkySQL and MariaDB will bring together industry visionaries, including Michael (Monty) Widenius and David Axmark, the original authors of the MySQL database, to share their insights on current and future …

Sergey Petrunia of the MariaDB project & Monty Program.

MySQL 5.5 GA at the end of 2010. MariaDB 5.3 RC towards the end of 2011 (beta in June 2011).

MySQL 5.5 is merged to Percona Server 5.5 which included semi-sync replication, slave fsync options, atuomatic relay log recovery, RBR slave type conversions (question if this is useful or not), individual log flushing (very useful, but not many using), replication heartbeat, SHOW RELAYLOG EVENTS. About 2/3rds of the audience use MySQL 5.5 in production, with only 2 people using semi-sync replication.

MariaDB 5.3 brings replication features brings group commit in the binary log, which is merged into Percona Server 5.5. Checksums for binlog events which is merged from MySQL 5.6. Sergey goes in-depth about the …

Steve Hardy of Zarafa.

Work that has been done to make Zarafa better. Why do you optimise your buffer pool? To decrease your I/O load. How can you do it? Buy more RAM, page compression, less (smaller) data, rearrange data.

MariaDB or Percona Server allows you to inspect your buffer pool (unsure if this is now available in MySQL 5.6). Giuseppe in the audience says this is available in MySQL 5.6, but Steve used this on MariaDB 5.2.

Strategies to fix it: Make records smaller. Remove indexes if you can use others almost as efficiently. Make records that are accessed around the same time have a higher chance of being on the same page. Use page compression. Buy more RAM. Try Batched Key Access (BKA) in MariaDB 5.3+.

Best to view the presentation since …

Stéphane Combaudon of Dailymotion.

Index: separate data structure to speed up SELECTs. Think of index in a book. In MySQL, key=index. Consider that indexes are trees.

InnoDB’s clustered index – data is stored with the Primary Key (PK) so PK lookups are fast. Secondary keys hold the PK values. Designing InnoDB PK’s with care is critical for performance.

An index can filter and/or sort values. An index can contain all the fields needed for the query you don’t need to go to the table (a covering index).

MySQL only uses 1 index per table per query (not 100% true – OR clauses), so think of a composite index when you can. Can’t index TEXT fields (use a prefix). Same for BLOBs and long VARCHARs.

Indexes: speed up queries, increases the size of your dataset, slows down writes. How big is the write slowdown? Simple test by Stephane, for in-memory workloads he says adding 2 keys makes performance 2x …

Sergey Petrunia of the MariaDB project.

What exactly is not working in MySQL? MySQL is poor at decision support/analytics. With large datasets you need special disk access strategies. Complex queries like insufficient subquery support and big joins are common int he MySQL world.

DBT-3 is used, scale=30, with a 75GB database and run a query “average price of item between a range of dates”. Query time took some 45 minutes to execute. Why? Run iostat -x to see what is going on. See that the CPU is mostly idle, so its an IO-bound load. Next you run SHOW ENGINE INNODB STATUS and you’ll see how many reads per second is happening. Possible solution is to get more RAM or get an SSD (good to speedup OLTP workloads, but analytics over data is probably not viable since SSDs are small and not cheap).

The MySQL/MariaDB …

Stephane Varoqui, Field Services SkySQL, Vlad Fedorkov, Director of PS, Sphinx Inc, Christophe Gesche, LAMP Expert, Delcampe, Herve Seignole, Web Architect, Groupe Pierre & Vacances Center Parcs – this is a big talk!

Pros: Filtering takes place on attributes in separate tables. Rely on the optimizer choice. HASH JOIN can help (MariaDB 5.3). Table elimination can help (MariaDB 5.2). ICP Index Condition Pushdown can help (MariaDB 5.3/MySQL 5.6). Max 80M documents at Pixmania, all queries come in less than 1s using 128GB of RAM (MariaDB 5.2). At PAP.fr, there is 16GB RAM with MariaDB 5.2.

Cons: CPU intensive (replication with many slaves). Need covering indexes to cover various !filter !order. Join & sorting cost on lazy filtering.

The more indexes you have in the system, the more you need to increase the main …

You may not realize it, but in MariaDB 5.2 and earlier and in MySQL up to version 5.5, START TRANSACTION WITH CONSISTENT SNAPSHOT does not give any guarantees of consistency between different storage engines.

For example, suppose you have two transactions which run in parallel:

Transaction T1:

BEGIN;
    SET @t = NOW();
    UPDATE xtradb_table SET a= @t WHERE id = 5;
    UPDATE pbxt_table SET b= @t WHERE id = 5;
    COMMIT;

Transaction T2:

SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
    START TRANSACTION WITH CONSISTENT SNAPSHOT;
    SELECT t1.a, t2.b
      FROM xtradb_table t1 INNER JOIN pbxt_table t2 ON t1.id=t2.id
    WHERE t1.id = 5;

In the above case, it is possible, even with a "consistent" snapshot, to see the changes in a transaction only in InnoDB/XtraDB tables, and not in PBXT tables.

Naturally, it would be much better if the changes were visible no matter the …

Part of every SkySQL subscription is paid to Monty Program to fund server development and improved functionality in MariaDB® (which is then sent upstream for inclusion in the MySQL® Server).

Thus, we'd like to know what you'd like to see in the upcoming releases of the server.

Please take a couple seconds (literally) and let your vote be heard:

http://www.skysql.com/content/new-server-functionality-have-your-say

We thank you and look forward to hearing your thoughts and ideas!

Instead of the usual text-heavy blog posts that appear here, I thought it would be fun to mix things up and do a screencast showing exactly how easy it is to upgrade MySQL to MariaDB:

Some notes:

• The laptop I’m using had MySQL 5.1.55 installed with one database (apart from the system database). Installing MariaDB does not impact existing data in any way and once the install completed I had instant access to my data.
• As part of the install you are given the option to set a new password for the root user. I choose to do it in the video, but you don’t need to. If you leave the password field blank the root password will not be changed. Other database users are preserved, of course.
• As with any database upgrade, before doing this to a production system you should have backups and test.

Links:

Links shown or mentioned in the video:

• …

I’m about to head to Paris to present at the February meetup of the MySQL User Group in Paris, France. It happens 1st February from 6-8pm at the Patricks Irish Pub. Its free to attend, and I understand that SkySQL keeps this event afloat.

I’m also heading to my first FOSDEM right afterwards and will definitely hang out at the MySQL & Friends Devroom. There is an amazing lineup of speakers, with all talks being about 25-30 minutes, it looks like it is going to be a lot of fun. To boot, Michael “Monty” Widenius will also be there, so expect lots of Salmiakkikossu.

If you want to …