Showing entries 101 to 110 of 1248
« 10 Newer Entries | 10 Older Entries »
Displaying posts with tag: Databases (reset)
Real-Time Data Movement: The Key to Enabling Live Analytics With Hadoop

An article about moving data into Hadoop in real-time has just been published over at DBTA, written by me and my CEO Robert Hodges.

In the article I talk about one of the major issues for all people deploying databases in the modern heterogenous world – how do we move and migrate data effectively between entirely different database systems in a way that is efficient and usable. How do you get the data you need to the database you need it in. If your source is a transactional database, how does that data get moved into Hadoop in a way that makes the data usable to be queried by Hive, Impala or HBase?

You can read the full article here: Real-Time Data Movement: The Key to Enabling Live Analytics With Hadoop

 


Filed under: …

[Read more]
Correctly setting your mysql prompt using sudo

If you run multiple MySQL environments on multiple servers it’s a good habit to set your MySQL prompt to double check which server you are on.
however, using the MYSQL_PS1 environment variable I found this does not work under sudo (the normal way people run sudo).

I.e., the following syntax’s work.

$ mysql
$ sudo su - -c mysql
$ sudo su - ; mysql

but the following does not.

$ sudo mysql

The trick is actually to ensure via /etc/sudoers you inherit the MySQL_PS1 environment variable.

echo "export MYSQL_PS1="`hostname` [d]> "" | sudo tee /etc/profile.d/mysql.sh
echo 'Defaults    env_keep += "MYSQL_PS1"' | sudo tee /tmp/mysql
sudo chmod 400 /tmp/mysql
sudo mv /tmp/mysql /etc/sudoers.d
Cross your Fingers for Tech14, see you at OSCON

So I’ve submitted my talks for the Tech14 UK Oracle User Group conference which is in Liverpool this year. I’m not going to give away the topics, but you can imagine they are going to be about data translation and movement and how to get your various databases talking together.

I can also say, after having seen other submissions for talks this year (as I’m helping to judge), that the conference is shaping up to be very interesting. There’s a good spread of different topics this year, but I know from having talked to the organisers that they are looking for more submissions in the areas of Operating Systems, Engineered Systems and Development (mobile and cloud).

If you’ve got a paper, presentation, or idea for one that you think would be useful, …

[Read more]
GUUG Frühjahrsfachgespräch 2014: CfP ends on May 31st!

The German Unix User Group (GUUG) will hold their annual conference "Frühjahrsfachgespräch" on September 23-26 this year (I know, not really "Frühjahr" anymore, but this is how it is).

The Call for Presentations is still open until May 31st. Talks can be proposed in German and English, and there are slots for longer tutorials as well.

The range of possible topics is broad, so if you think you have anything interesting to share with a very passionate and technical audience of sysadmins and developers, here are some suggestions:

  • Operating Systems/Applications: architectures, privilege concepts, new developments, administration, mobile systems
  • Relevant new OS Kernel features: new developments in Linux-, BSD- or other Spen …
[Read more]
MMUG7: Madrid MySQL Users Group meeting to take place on 24th April 2014

Madrid MySQL Users Group will have its next meeting on the 24th of April. Details can be found on the group’s Meetup page. We plan to talk about WebScaleSQL and I will give a short presentation on how to build WebScaleSQL RPMs on CentOS 6.  The meeting will be in Spanish. We’ve changed the place that … Continue reading MMUG7: Madrid MySQL Users Group meeting to take place on 24th April 2014

Never use floats for money

UPDATE: Several people have commented that decimal(10,2) is not correct for money, since sometimes currencies go out to more than 2 decimal places. Others claimed that storing cents (or base unit) as integers make it simpler to perform calculations (thanks, Kevin Farley for your comment). Regardless of what you choose – don’t use floats for money. If you do use integers, I would include the base unit in the name to avoid confusion (AmountInCents).

Data types make all the difference in the world when you’re designing your database. The choices you make now will affect the quality of your data, as well as application performance. I’m going to focus on one issue in this article: why you should always use decimals to represent money. Let’s jump in and see why that’s true.

An example of floats gone wrong

Let’s use a really, really simplified accounting ledger. It’s just three fields, an entry id, …

[Read more]
WebScaleSQL RPMs for CentOS 6

Looks like this post was rather unclear. See the bottom for how to build the rpms quickly.

WebScaleSQL was announced last week. This looks like a good thing for MySQL as it provides a buildable version of MySQL which includes multiple patches from Facebook, Google, LinkedIn, and Twitter needed by large users of MySQL, patches which have not been incorporated into the upstream source tree.  Making this more visible will possibly encourage more of these patches to be brought into the code sooner.

The source is provided as a git repo at https://github.com/webscalesql/webscalesql-5.6 and as detailed at http://webscalesql.org/faq.html the documentation says there is currently no intention to provide binaries. …

[Read more]
Continuent Replication to Hadoop – Now in Stereo!

Hopefully by now you have already seen that we are working on Hadoop replication. I’m happy to say that it is going really well. I’ve managed to push a few terabytes of data and different data sets through into Hadoop on Cloudera, HortonWorks, and Amazon’s Elastic MapReduce (EMR). For those who have been following my long association with the IBM InfoSphere BigInsights Hadoop product, and I’m pleased to say that it’s working there too. I’ve had to adapt Robert’s original script to work with the different versions of the underlying Hadoop tools and systems to make it compatible. The actual performance and process is unchanged; you just use a different JS-based batchloader script to work with different tools.

Robert has also been simplifying some of the core functionality, such as configuring some fixed pre-determined formats, so you no longer have to explicitly set the field and record separators.

I’ve also been …

[Read more]
MySQL 5.6 GTIDs: Evaluation and Online Migration

A colleague and I have been looking at GTID on MySQL recently and you may be interested in the blog post that results from that. You can see it here. http://blog.booking.com/mysql-5.6-gtids-evaluation-and-online-migration.html.

 

Interviewing for a Database Developer

I work for a firm that’s heavily invested in SQL – a team that needs to have developers who know their way around relational databases and MySQL in particular. I want to show you how I run interviews for our development positions.

Method

Everybody has their own methods and opinions on how to conduct technical interviews. I’ve found that I generally dislike interviews that focus either on whiteboard puzzles or obscure technical details, since they don’t really show how well the candidate is at what really matters: building functioning, quality apps. I really like running the interview like we’re talking about the design for a new product. I want to figure out the requirements, mull over the data model, and write some simple queries to make sure we can show the data we need to.

This process should show two things: the candidate has a good enough grip on the MySQL database that they can comfortably build a system …

[Read more]
Showing entries 101 to 110 of 1248
« 10 Newer Entries | 10 Older Entries »