Docker is one of the fastest growing trends in IT. It allows fast deployment of services and applications on a Linux machine (and, with some limits, on other operating systems). Compared to other methods of deploying databases, such as virtual machines or application isolation, it offers faster operations and better performance.
Many people, surprised by the sudden advance of this technology, keep asking What is Docker? And why you should use it?
I will write soon an article with a deep comparison of the three methods (VM, container, sandbox), but for now, we should be satisfied with a few basic facts:

• Docker is a Linux container. It deploys every application as a series of binary …

I was wondering if it is possible to write a MySQL User Defined Function (UDF) in Go.  
So I tried and I got a very basic UDF working.

mysql> SELECT udf_fileexists_go("/etc/hosts");
+---------------------------------+
| udf_fileexists_go("/etc/hosts") |
+---------------------------------+
|                               1 |
+---------------------------------+
1 row in set (0.00 sec)

mysql> SELECT udf_fileexists_go("/nonexistend");
+-----------------------------------+
| udf_fileexists_go("/nonexistend") |
+-----------------------------------+
|                                 0 |
+-----------------------------------+
1 row in set (0.00 sec)

This is nowhere near production quality, so be careful.

The code is here:https://github.com/dveeden/udf_fileexists_go/blob/master/udf_fileexists_go.go. …

The Korean MySQL Power User Group gets a special guest speaker next weekend (Oct 31 2015 – 4pm – 4:33’s offices in Gangnam — nearest train stop is Samseong station, Line 2 — post requires Cafe Naver login) — Mark Callaghan (Small Datum, @markcallaghan, and formerly High Availability MySQL). I’ve been to many of their meetups, and I think this is a great opportunity for many DBAs to learn more about how Mark helps make MySQL and MongoDB better …

Last week we had the MySQL Meetup with MariaDB Developers in Amsterdam, which went on easily for about 3.5 hours. Thanks to all for listening (these were lightning talks, not with a strict 5 minute clock with Q&A thrown in), and Daniël van Eeden for organising this at the eBay offices (whom kindly provided pizza, beer and soft drinks as well). We had many talks, and I’ve managed to put up most of the slides into a Google Drive folder, so feel free to access the …

[…] the VPC and I would like to connect to it using MySQL workbench. I have followed the steps detailed here, however in “Step 6: Setting up remote SSH Configuration”, it asks me to “Provide […]

This Log Buffer Edition covers some more Oracle, SQL Server and MySQL blog posts from across the world.

Oracle:

• Should I monitor the MGMTDB database?
• Connecting MAF Applications to Mobile Cloud Service
• JRE 6, 7, and 8 now certified with EBS 11i, 12.1, and 12.2
• The database writer copies data blocks from the buffer cache onto disk. The db_writer_processes initialization parameter determines how many processes will do this task. Its default value is 1 or cpu_count / 8, whichever is greater. I found an Oracle 9 database on a …

Personal Projects with the Internet of Things

So you want to do a personal project with the Internet of Things (maybe a home automation or metrics collection or something else)? In this blog post I will tell about my recent experience with this. I will give a talk on this topic at Oracle OpenWord 2015 (Tuesday, Oct 27, 6:15 p.m., Moscone South, 274).

Here is what I did: I was looking for the best place to plant some trees in my backyard. I learned that I need to know how much sun I have in the backyard before planting (some trees need full sun, while others need partial sun or shade). So I needed to measure the sunlight in different spots.

The “old” way of doing it was to use …

"Split Brain" is the term commonly used for a cluster whose nodes have different contents, rather than identical as they should have. Typically, a "split brain" situation is the DBA's nightmare, and the Galera software is designed to avoid it. Galera is very successful in that avoidance, and it needs some special steps by the DBA to achieve "split brain". Here is how to do it - or, for most DBAs, what to avoid doing to not get a split-brain cluster.

Galera's Design

First, let's remember how Galera is operating:

• The Galera software ensures that all nodes participating in a cluster will start from identical contents, by doing a "snapshot state transfer" (SST) of all current data to a newly joining node.
• When the cluster is running, Galera transfers all changes (transactions) to all cluster nodes and applies them (or rolls back and ignores, in the case of a conflict).
• If some connections get …

Requires ClusterControl 1.2.11 or later. Applies to MySQL based clusters.

During the life cycle of Database installation it is common that new user accounts are created. It is a good practice to once in a while verify that the security is up to standards. That is, there should at least not be any accounts with global access rights, or accounts without password.

Using ClusterControl, you can at any time perform a security audit.

In the User Interface go to Manage > Developer Studio. Expand the folders so that you see s9s/mysql/programs. Click on security_audit.js and then press Compile and Run.

If there are problems you will clearly see it in the messages section:

…

One of the common questions we get during sales demos is “does VividCortex give advice on my database’s configuration?” The assumption is that since our product sees lots of information about the database, operating system, and current configuration, it can “optimize” the database configuration. Or, at least, point out really obviously bad things? Surely that is not too hard to do?

VividCortex doesn’t do that, and there are good reasons why. By way of explanation I’d like to tell a few war stories. Warning: you’re probably going to vow never to look at auto-generated tuning advice again.

Get Down Off The Ledge

At one point, a significant chunk of my career and earnings consisted of undoing the damage caused by configuration advisors. It was often very hard to convince people to reverse the changes the configuration advisors had urged them to make. It’s a psychological problem, not a technical one.