The latest from the MySQL community

MySQL Cluster: El ‘qué’ y el ‘cómo’.

Para aquellos que encuentran mucho sobre MySQL en Inglés pero poco en Español: mi pequeña aportación.
En el enlace tenéis información sobre qué es MySQL Cluster y cómo funciona. Incluso con ejemplos técnicos para romper las barreras y ayudar a simplificarlo (espero).

¡A disfrutar!

While testing installation steps with MySQL 5.7.7-rc, surely you will find much more improvements, changes, deprecated functionality and etc.

The interesting one is activating VALIDATE PASSWORD PLUGIN via mysql_secure_installation script. Which we use by mean “securing” MySQL installations.

I will write a separate topic about MySQL 5.7.7-rc installation steps from source, with related BUG reports.

So after first run:

[root@centos7_vm mysql]# bin/mysql_secure_installation --socket=/opt/mysql/datadir/mysqld-new.sock
Securing the MySQL server deployment.
Connecting to MySQL server using password in '/root/.mysql_secret'

If you notice, now script trying to connect to MySQL using a temporary password which is generated for root@localhost and logged into hidden .mysql_secret file.

VALIDATE PASSWORD PLUGIN can be used to test passwords
and improve security. It checks the strength of …

If you are using Galera Cluster in multi-master mode, you will most likely run into transaction conflicts if two clients attempt to modify the same row at the same time. Such conflicts are reported a deadlock errors to the application.

Legacy applications are frequently unable to handle transaction conflicts properly and may not provide sufficient information to debug the source of the problem.

If the wsrep_log_conflicts option is set, Galera can output all the information about transaction conflicts that is available to it to the error log. As it is a dynamic option, you can enable it while the server is running, collect some entries for examination, and disable it to avoid filling up the log.

Decoding the Output

The output from wsrep_log_conflicts may look a bit intimidating at first, but in fact contains a lot of information that can be used to pin-point the offending application, module or SQL operation. The …

DC Energy is a trader in the commodities markets that relies heavily on MySQL. Since trading is time-sensitive, database management and minimal system downtime is a high priority. Prior to deploying VividCortex, DC Energy used query logs and custom tools, scripts and metrics to find and resolve problems. Internal tools did not provide a way to quickly review and assess the enormous amount of data available, and gaining insight into performance was time consuming.

In March 2013, DC Energy began using VividCortex. Joe Kelly, DC Energy associated, highlighted the benefits since installation:

VividCortex has an intuitive interface, and it’s clearly built by a team that understands monitoring because it only shows us what we need to know. It does not overwhelm us with a lot of information we don’t want. Everything I want is accessible, and I am not bogged down by extraneous information.

This has led to faster diagnosis and …

Well it has been awhile since I posted, sorry about that. Today I was watching reruns of the TV show Fringe and when Walter referenced the Fibonacci Sequence I got side tracked with MySQL options for this.

Now this post already existed:

• http://slava-technical.blogspot.com/2010/10/fibonacci-numbers-built-with-sql.html

So I took that post and expanded on it a little, the result is a procedure that you can call and return the range within the Fibonacci Sequence that you are after.

The procedure is below:

delimiter //
CREATE PROCEDURE `Fibonacci`(IN POS INT, IN RANG INT, IN LIMTED INT)
BEGIN
       select FORMAT(Fibonacci,0) AS Fibonacci from (
…

The MariaDB project is pleased to announce the immediate availability of MariaDB Galera Cluster 10.0.20 and MariaDB Galera Cluster 5.5.44. These are Stable (GA) releases.

Download MariaDB Galera Cluster 10.0.20

Release Notes Changelog What is MariaDB Galera Cluster?

Download …

When I joined Pinterest, my first three weeks were spent in Base Camp, where the newest engineering hires work on real production issues across the entire software stack. In Base Camp, we learn how Pinterest is built by building it, and it’s not uncommon to be pushing code and making meaningful contributions within just a few days. At Pinterest, newly hired engineers have the flexibility to choose which team they’ll join, and working on different parts of the code as part of the Base Camp experience can help with this decision. Base Campers typically work on a variety of tasks, but my project was a deep dive into a MySQL performance optimization project.

Pinterest, MySQL and AWS, oh my!

We work with MySQL running entirely inside Amazon Web Services (AWS). Despite using fairly high-powered instance types with RAID-0 SSDs and a fairly simple workload (many point selects by PK or simple ranges) that peaks around 2,000 …

I have created a small program to extract data from an Oracle database in a format suitable for importing into MariaDB (and MySQL I guess). It is pretty fast as it is written in C and uses the OCI interface. Also, it supports most of the Oracle basic types, including BLOB, CLOB and LONG. UTF8 is also supported and there are many generic features, as well as some features specific for later import into MariaDB.

Download the 1.0 version from Sourceforge where the programs source, that is using autotools for building, as well as documentation is available. I have not tested to build on any other version of Oracle than 11, but maybe someone could help me there.

/Karlsson

In the MySQL team, we have been planning for some time to remove the implicit sorting that is provided by GROUP BY. In doing so, we will make a number of existing queries faster (by no longer requiring a sort) as well as unlock opportunities to implement further optimizations.

This is one of the more complicated behaviours to remove, because it is not possible to tell if an application relies upon implicit ordering. Since a GROUP BY query without an ORDER BY clause is a valid query, it is also not reasonable to issue deprecation warnings.

However, one piece of the puzzle that was missing when I last wrote about this problem, is that MySQL 5.7 will …

This Log Buffer Edition gathers a wide sample of blogs and then purifies the best ones from Oracle, SQL Server and MySQL.

Oracle:

• If you take a look at the “alter user” command in the old 9i documentation, you’ll see this: DEFAULT ROLE Clause.
• There’s been an interesting recent discussion on the OTN Database forum regarding “Index blank blocks after a large update that was rolled back.”
• 12c Parallel Execution New Features: 1 SLAVE distribution
• Index Tree Dumps in Oracle 12c …