We’ll be publishing a series of posts on OpenStack and Trove over the next few weeks, diving into their usage and purpose. For readers who are already familiar with these technologies, there should be no doubt as to why we are incredibly excited about them, but for those who aren’t, consider this a small introduction to the basics and concepts.

What is Database as a Service (DBaaS)?
In a nutshell, DBaaS – as it is frequently referred to – is a loose moniker to the concept of providing a managed cloud-based database environment accessible by users, applications or developers. Its aim is to provide a full-fledged database environment, while minimizing the administrative turmoil and pains of managing the surrounding infrastructure.

Real life example: Imagine you are working

If you try to install the TokuDB storage engine on a modern Linux distribution it might fail with following error message:

2014-07-17 19:02:55 13865 [ERROR] TokuDB will not run with transparent huge pages enabled.
2014-07-17 19:02:55 13865 [ERROR] Please disable them to continue.
2014-07-17 19:02:55 13865 [ERROR] (echo never > /sys/kernel/mm/transparent_hugepage/enabled)

You might be curious why TokuDB refuses to start with Transparent HugePages. Are they not a good thing… allowing smaller kernel page tables and less TLB misses when accessing data in the buffer pool? I was curious, so I asked Tim Callaghan this very question.

This problem originates with TokuDB using jemalloc memory allocator, which uses a particular trick to deal with memory fragmentation. The classical problem with memory

You probably know about VividCortex's Top Queries view, which shows MySQL query activity on one or many systems in industry-leading detail. But did you know you can also see what's happening on the operating system? Not only do we capture fine-grained metrics about CPU, network, and so on, but we capture per-process metrics.

Behold:

This is pretty life-changing when you're trying to figure out what's happening in your database. How many times have you gotten tunnel vision trying to find the cause of a performance problem by looking at MySQL log files or metrics, and later discovered that the problem was due to a rogue cron job or other process?

The Top Processes view also serves as an easy way to demonstrate how lightweight the VividCortex agents are. The screenshot

We are glad to annouce the new release of dbForge Studio for MySQL, v6.2.

We designed Percona Cloud Tools (both hardware and software setup) to handle a very high-intensive MySQL write workload. For example, we already observe inserts of 1bln+ datapoints per day. So I wanted to share what kind of hardware we use to achieve this result.

Let me describe what we use, and later I will explain why.

Server:

• Chassis: Supermicro SC825TQ-R740LPB 2U Rackmount Chassis
• Motherboard: Supermicro X9DRI-F dual socket
• CPU: Dual Intel Xeon Ivy Bridge E5-2643v2 (6x 3.5Ghz cores, 12x HT cores, 25M L3)
• Memory: 256GB (16x 16GB 256-bit quad-channel) ECC registered DDR3-1600
• Raid: LSI MegaRAID 9260-4i 4-port 6G/s hardware RAID controller, 512M buffer
• MainStorage: PCIe SSD HGST FlashMAX II 4.8TB
• Secondary

We just wanted to make it official: Severalnines ClusterControl now supports MariaDB 10!

As most of you know will know by now, MariaDB 10 is the newest and most advanced version of the popular MariaDB relational database system. Whilst remaining application-compatible with the MySQL database, it adds many new capabilities to address the most challenging web and enterprise application use cases. Cluster deployments would be based on MariaDB Galera Cluster 10, which is a complete merge of MariaDB 10.0.12 and Galera Cluster. 

ClusterControl for MariaDB Clusters

Percona is glad to announce the new release of Percona XtraDB Cluster 5.6 on July 21st 2014. Binaries are available from downloads area or from our software repositories. We’re also happy to announce that Ubuntu 14.04 LTS users can now download, install, and upgrade Percona XtraDB Cluster 5.6 from

How To Install Nginx With PHP And MySQL (LEMP Stack) On CentOS 7

Nginx (pronounced "engine x") is a free, open-source, high-performance HTTP server. Nginx is known for its stability, rich feature set, simple configuration, and low resource consumption. This tutorial shows how you can install Nginx on a CentOS 6.5 server with PHP support (through PHP-FPM) and MySQL (Mariadb) support.

I recently worked on a case where one node of a Galera cluster had its schema desynchronized with the other nodes. And that was although Total Order Isolation method was in effect to perform the schema changes. Let’s see what happened.

Background

For those of you who are not familiar with how Galera can perform schema changes, here is a short recap:

• Two methods are available depending on the value of the wsrep_OSU_method setting. Both have benefits and drawbacks, it is not the main topic of this post.
• With TOI (Total Order Isolation), a DDL statement is performed at the same point in the replication flow on all nodes, giving strong guarantees that the schema is always identical on all nodes.
• With RSU (Rolling Schema Upgrade), a DDL statement is not replicated to the other nodes.

When you send a query to MySQL, you usually don't need to think explicitly about the types of the expressions in your query. If you compare this to a lot of programming languages, you'll find that it's not always the way things work. In strongly typed languages like Java, for example, typing is very strict.

In this respect, MySQL is much more like a dynamically typed language such as PHP or Perl --- a DWIM (do what I mean) typing system. Yet, internally, every expression in MySQL has a type, and it does conversions amongst them as needed.

Sometimes, you might wonder how does this query work and exactly what's happening to the variables in these expressions? Importantly, does it always work right?

Examples of MySQL Type Conversion

Let's

The Percona Managed Services team recently faced a somewhat peculiar client issue. We’d receive pages about their MySQL service being unreachable. However, studying the logs showed nothing out of the ordinary…. for the most part it appeared to be a normal shutdown and there was nothing in anyone’s command history nor a cron task to speak of that was suspicious.

This is one of those obscure and peculiar (read: unique) issues that triggered an old memory; I’d seen this behavior before and I had just the tool to catch the culprit in the act.

Systemtap made diagnostics of this issue possible and I can’t state enough how much of a powerful and often under-utilized tool set systemtap really is.

cat >

This week we continue our series on Common Schema and talk about different ways to look at the processlist, help with the query profiler, and some internal Common Schema tables. Ear Candy is about RHEL 7.0 using MariaDB, and At the Movies is The Human Postmortem.

This week we continue our discussion about Common Schema by talking about security views and schema analysis views. Ear Candy is that apt repositories for MySQL are available, and At the Movies is about copyright vs. civil liberties.