Earlier this month I wrote about vmstat iowait cpu numbers and some of the comments I got were advertising the use of util% as reported by the iostat tool instead. I find this number even more useless for MySQL performance tuning and capacity planning.

Now let me start by saying this is a really tricky and deceptive number. Many DBAs who report instances of their systems having a very busy IO subsystem said the util% in vmstat was above 99% and therefore they believe this number is a good indicator of an overloaded IO subsystem.

Indeed – when your IO subsystem is busy, up to its full capacity, the utilization should be very close to 100%. However, it is perfectly possible for the IO subsystem and MySQL with it to have plenty more capacity than when utilization is showing 100% – as I will show in an …

Genoscope, the French National Sequencing Center, was created in 1997 and is one of the largest sequencing centers in Europe. Its mission is to acquire, to "sequence" and to analyze the genetic information of various organisms presenting a scientific, medical or economic interest. DNA sequencing is the process of determining the precise order of nucleotides within a DNA molecule. Genoscope produces various types of data, such as complete or partial genome sequences, that are then compared and analyzed. Following its role as a major actor in the Human Genome Project, Genoscope has changed its orientation toward environmental genomics. Since 2007, Genoscope is part of CEA, the French Alternative Energies and Atomic Energy Commission.

Challenges

• Make a large amount of scientific data available to biologists worldwide via a database combining performance, ease of use and cross-platform …

Créé en 1997, le Genoscope - Centre National de Séquençage - est un grand équipement au service de la communauté scientifique. Sa mission est d'acquérir, de "séquencer", et d'analyser l'information génétique de divers organismes d'intérêt scientifique, médical ou économique. Concrètement, le séquençage consiste à déterminer l'ordre dans lequel s'enchaînent les molécules élémentaires qui constituent les molécules d'ADN. Le Genoscope produit des données de nature diverse - séquences entières ou partielles de génomes ou de produits d'expression des gènes - qu'il compare et interprète. Après avoir été l'un des acteurs du projet génome humain, le Genoscope met aujourd'hui le cap vers la génomique environnementale. Depuis 2007, le Genoscope est intégré à l'institut de Génomique du CEA, le Commissariat à l'énergie atomique et aux énergies alternatives.

Défis

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Tesora, previously called Parelastic, asked Percona to do a sysbench benchmark evaluation of its Database Virtualization Engine on specific architectures on Amazon EC2.

The focus of Tesora is to provide a scalable Database As A Service platform for OpenStack. The Database Virtualization Engine (DVE) plays a part in this as it aims at allowing databases to scale transparently across multiple MySQL shards.

DVE was open sourced last week. Downloads and …

Infrequent SQL developers often get confused about when to put parentheses and/or aliases on derived tables. There has been this recent Reddit discussion about the subject, where user Elmhurstlol was wondering why they needed to provide an alias to the derived table (the subselect with the UNION) in the following query: SELECT AVG(price) AS AVG_PRICE … Continue reading Should I Put That Table Alias or Not? →

MySQL Bugs On Dolphins, Panda's and Bugs

Like any good OpenSource project the MySQL Bugs website is open for anyone to search through. This ofcourse doesn't include the security bugs.

There is a second collection of bugs in the My Oracle Support and these bugs are only accesseble by customers with a support contract. Even when I have access to MOS I still prefer to use the community bugs site. For service requests etc. I would use MOS.

The openness of the bugs database is one of the topic the IOUG MySQL Council discusses with Oracle.

The bugs database has more to offer than just information about initial bugs:

• Bugs Statistics: This has a big matrix with …

During last April’s Percona Live MySQL Conference and Expo, TokuDB celebrated it’s first full-year as an open source storage engine. I still remember reading the official announcement and the expectations it created one year ago. The premises were very interesting as it had the potential of helping MySQL manage “big data” in a way InnoDB just couldn’t. It also provided additional interesting features like “hot schema changes,” all the while making our dear flash storages last longer.

While I’ve kept an eye on the evolution of TokuDB this past year, I reckon I haven’t given it a try…. until recently, when a …

InnoDB has proven to be a reliable data storage engine for modern, high concurrency database systems. It is fully ACID compliant, and supports a wide range of isolation modes, from READ-UNCOMMITEED to SERIALIZABLE.

InnoDB multiversion concurrency control (MVCC) enables records and tables to be updated without the overhead associated with row-level locking mechanisms. The MVCC implementation in InnoDB largely eliminates the need to lock tables or rows during updates, and enables good performance for high concurrency workloads.

To learn more about this subject and related performance tuning topics tuning, take the MySQL Performance Tuning training course. This 4-day, instructor-led course is available as:

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Section 5: "Prepare Eclipse for profiling" 5.1 INTRODUCTION

In this part we will prepare Eclipse to profile our recently compiled(see Part 3) MariaDB(or MySQL).
Profiling means basically measuring where the time is spent by the application.
You may be interested in knowing how much time is spent in a specific function execution,
or you may want to know statistics about the dustribution of function calls, that is operating a data aggregation.

read more

Well, every now and then, when we began to start a new project or app, which has some data storage requirement, we have a deep intriguing thought as to how best represent the data structure so as to support a variety of needs including but not limited to (ACID rules):

1. Normalization
2. Reliability
3. Consistency
4. And many others

Below, I provide a set of steps which you can follow to arrive at a data model that correctly suites your requirements.

Steps:

1. Identify the project or app requirements / specifications and business rules which tell you what your app will be able to do when it is ready.
2. From these business rules, identify possible objects for each business rule and mark them in a paper using rectangular sections like authors, posts etc.
3. Once you have recognized the …