Everybody loves free. It is the best marketing term one could use. Once you say “FREE” the people come running. Free makes you very popular. Whether you are a politician offering something for free, or a company providing free stuff, you gain instant popularity.

Xeround is shutting down their MySQL Database as a Service (DBaaS) because their free instances, while popular, simply did not convert into sufficient paid instances to support the company. While I am sad to see them fail, because I appreciate the hard work required to deliver database technology, this announcement was not unexpected.
My company was at Percona Live, the MySQL conference, and I had some additional conversations along these same lines. One previously closed source company announced that they were open sourcing their code, it was a very …

Everybody loves free. It is the best marketing term one could use. Once you say “FREE” the people come running. Free makes you very popular. Whether you are a politician offering something for free, or a company providing free stuff, you gain instant popularity.

Xeround is shutting down their MySQL Database as a Service (DBaaS) because their free instances, while popular, simply did not convert into sufficient paid instances to support the company. While I am sad to see them fail, because I appreciate the hard work required to deliver database technology, this announcement was not unexpected. My company was at Percona Live, the MySQL conference, and I had some additional conversations along these same lines. One previously closed source company announced that they were open sourcing their code, it was a very popular …

Last week I had to present a tutorial at Percona Live 2013, a presentation at SkySQL’s MySQL & Cloud Database Solution Day and last but not least, a presentation on a Saturday morning at Linuxfest Northwest. It wasn’t easy, but giving the presentations after our announcement early in the week about going open source was very exciting given the warm reception we got from the MySQL Community.

Following …

MySQL Cluster Manager 1.2.3 is now available to download from My Oracle Support.

Details on the changes can be found in the MySQL Cluster Manager documentation .

Documentation is available here.

In an earlier blog post, I managed to confuse myself as to when a subquery was executed. It is not very clear from the output of EXPLAIN where the execution of a subquery takes place. Let's take a look at the following example query (Query 17 in the DBT-3 benchmark):

select sum(l_extendedprice) / 7.0 as avg_yearly
from lineitem, part
where p_partkey = l_partkey
  and p_brand = 'Brand#33' and p_container = 'LG CAN'
  and l_quantity < (
 select 0.2 * avg(l_quantity)
 from lineitem
 where l_partkey = p_partkey
);

If you run EXPLAIN on this query, you will see the following execution plan:

+----+--------------------+----------+------+---------------------------------+---------------------+---------+---------------------+---------+-------------+
| id | select_type …

A friend wrote to me recently with a question. He was working on a method to ship application metrics to statsd on a 1 minute interval. He had three examples of how to estimate the number of rows in a table and he wanted to know the difference between them.

Data length/average row length

The example given:

mysql> select DATA_LENGTH/AVG_ROW_LENGTH from INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME = 'line_items';
+----------------------------+
| DATA_LENGTH/AVG_ROW_LENGTH |
+----------------------------+
|              10497541.7528 |
+----------------------------+
1 row in set (0.03 sec)

I have actually never thought of using this method! I don’t think it’s accurate though, since data length has deleted space + additional preallocated or overhead space. For example a page file is only …

I find a good interview question for a MySQL DBA position is to ask what the following commands actually do in InnoDB, which has been the default storage engine since MySQL 5.5. From my perspective there is a lot of miss-understanding what still applies.

ANALYZE TABLE

From the MySQL manual:

ANALYZE TABLE analyzes and stores the key distribution for a table. During the analysis, the table is locked with a read lock for InnoDB and MyISAM.

What this means is, as part of query optimization MySQL will often have to decide which is the best index if there are multiple candidates, which indexes should be avoided, and what order should tables be joined in. Indexes need to eliminate work - so if for example you were trying to index a column called “Country” in a table full of all people in the USA, then it would be faster to …

This is a guest post from Jelastic.

Many developers use master-slave replication to solve a number of different problems, including problems with performance, supporting the backup of different databases, and as a part of a larger solution to alleviate system failures. Traditionally, master-slave replication is done with real servers, but it can also be done with cloud database servers. This guest post from Jelastic (originally published here) describes how to set up MariaDB master-slave replication using their Jelastic PaaS (Platform as a Service).

Replication Overview

Master-slave replication enables data from one database server (the master) to be replicated to one or more other database servers (the …

Wed, 2013-05-01 18:54 About the Author Daniel Bartholomew

Daniel is a System Administrator, Documenter, and author of the recently released Getting Started with MariaDB

Many developers use master-slave replication to solve a number of different problems, including problems with performance, supporting the backup of different databases, and as a part of a larger solution to alleviate system failures. Traditionally, master-slave replication is done with real servers, but it can also be done with cloud database servers. This guest post from Jelastic (originally published here) describes how to set up MariaDB master-slave replication using their Jelastic PaaS (Platform as a Service).

Replication Overview

Master-slave replication enables data from one …

I’ve put online the slides for the two talks that I сo-presented at the Percona Live conference:

• Advanced query optimizer tuning and analysis tutorial (slideshare, pdf)
• MariaDB Cassandra interoperability session (slideshare, …