September 21, 2024
Create a bootable Ubuntu installer on a partitioned USB drive
Simple steps to create a bootable Ubuntu Live CD / Installer on a USB drive that has more than one partition.
September 16, 2024
Modelling Meter Rates in Rails
Thinking about modelling meter rates with and without an end date on the database row and the surprising difference in complexity.
August 14, 2024
Load a mysql table into sqlite quickly
I recently had a need to copy about 18M rows from Mysql to a sqlite database. The mysql dump measured about 1.2GB.
April 09, 2024
Hibernate on Ubuntu 22.04 and 24.04 without uswsusp
Getting my laptop to hibernate successfully with Ubuntu 22 was a little tricky. Most of the online resources mention a command swap-offset which I think comes from the package uswsusp. That package is no longer part of Ubuntu. These are the steps I used to get Hibernate working on a Lenovo T490 with Ubuntu 22.
April 05, 2024
Intellij development on Windows with WSL and Docker and Ruby
Having left Windows behind some 10 years ago, I recently heard about WSL via [DHH](https://twitter.com/dhh?lang=en) tweeting about trying it and leaving Mac OS behind. So I decided to give it a try. Most of my development these days is using Intellij for Java (or Ruby on the side).
February 09, 2024
Rails development in docker with Rubymine or Intellij
The last time I tried to install Rails on my mac, I got into all sorts of build and compile errors that made it painful to even get started. These days I try to use Docker to make setup and laptop moves easier. Having a need for a new Rails app, I though it would be interesting to try a fully dockerized dev environment.
March 20, 2023
Whitelisting a Dynamic IP in with iptables
Using No IP to whitelist a dynamic home internet ip address in iptables
March 17, 2023
Docker and the iptables firewall
Docker likes to make things simple. If you expose a port on a host, then by default it is open to anything which can connect to the host, even if the host firewall by default drops all incoming requests. This post discusses how to secure your firewall with Docker in the picture.
January 26, 2023
How to stop your iphone charging at a defined percentage
Instructions on how to use a Tapo smart plug and iOS shortcuts to stop charging your iPhone at 80%, or whatever level you want.
January 19, 2021
Resetting ByteBuffers to zero in Java
Comparing various ways to reset a Java ByteBuffer to its initial state, containing all zeros.
May 08, 2020
The Memory Overhead of Java Ojects
Some notes on how much memory different Java objects use, and some ways to reduce the overhead
May 30, 2017
Merge Empty HBase Regions
If you have ascending row keys and cells with TTL set on them, you can end up with a lot of empty regions that need merged.
February 06, 2017
Writing Data To HDFS From Java
Some notes on writing data to HDFS from a Java application
October 05, 2015
Setup Open LDAP on Centos 6
A short guide to get Open LDAP up and running on Centos 6, allowing other machines to authenticate with the Open LDAP server.
September 23, 2015
Loading Stack Exchange Data Dumps to Hadoop and Hive
A simple tutorial showing how to load Stack Exchange data dumps to Hive
September 24, 2015
Map Reduce with XML Input and Multiple Avro Outputs
A map reduce job to convert the Stack Exchange data dumps into Avro format from their original XML format.
July 06, 2015
Create a RPM from a Ruby gem
A simple example to create an RPM from a Ruby gem using rpmbuild
May 05, 2015
Map Reduce Counters
A short post illustrating how to create custom counters in map reduce jobs
April 27, 2015
Map Reduce Multiple Outputs
Another simple map reduce example demonstrating how to use MultipleOutputs to write to more than one file.
April 21, 2015
Comparing Sequence Files, ORC Files and Parquet Files
A quick look at the performance characteristics of then Hadoop Sequence, ORC and Parquet file formats
March 02, 2015
Experimenting with Flume Performance
A summary of some course tests I performed against Flume to see how different settings affect performance
January 25, 2015
Creating Centos or Redhat init scripts
A description on how to create SysV init scripts for Redhat / Centos systems, including a script template.
January 06, 2015
Unit Testing Map Reduce Programs With MRUnit
Using MRUnit to test a simple Hadoop map reduce program, including how to run the job without a Hadoop cluster
December 15, 2014
Creating a Simple Map Reduce Program for Cloudera Hadoop
An example of a very simple Java Map Reduce program that counts the number of unique works in a CSV delimited data.
December 10, 2014
Maven Config For Cloudera Map Reduce Programs
Steps to setup a Maven project to develop Map Reduce applications against Cloudera Hadoop.
October 23, 2014
Creating a RPM From the Java JDK Tar File
Steps describing how to convert a tar file of precompiled software, in this case the Java JDK, into an installable RPM.
October 02, 2014
Speeding up Ember CLI build times on OS X
Using a RAM disk for an Ember CLI projects tmp directory to speed up compile times
September 04, 2014
Emacs Setup for Version 24.3
An more modern and improved Emacs setup, including ECB and Enhance Ruby Mode, Javascript mode and more.
August 11, 2014
Check Apache or Nginx Compression Is Working
A quick way to check your webserver is compressing html, JS and CSS.
August 07, 2014
Ruby Performance Analysis Tools
A selection of tools that can be used to analyze the performance of Ruby programs.
October 15, 2013
Profiling a Mysql Query
How to get Mysql to tell you how many reads it performs when running a query.
October 14, 2013
Statically Compiling Git
If you don't have access to a C compiler, or have the ability to install an RPM on a machine, but you still want to use git, you need to create yourself a statically linked binary on another machine and copy it over.
August 29, 2013
Creating a Basic Hive UDF
A summary of the steps required to create a User Defined Function (UDF) in Hive.
April 10, 2013
Test Hard Disk Speed With dd
It is pretty simple to test the speed of writing a large file with the dd command, but you need to know about the subtle options available when writing a file to actually test the speed of a storage device.
March 07, 2013
PLSQL Unit Test
Continuing on my track of creating Ruby Gems to help with database interactions, I created PLSQL Unit Test.
February 28, 2013
Data Factory
When I was writing PLSQL unit tests with Ruby, I came across a need to stage test data into tables. I didn't really want to involve an ORM like Active Record, but working with RAW insert statements quickly became a chore, so I created the Data Factory gem.
February 12, 2013
Simple Oracle JDBC
The first, and hopefully not last Ruby Gem I have released. This one is a wrapper around Oracle JDBC connections to make it easier to make database calls.
January 23, 2013
One Large Redis or Many Smaller Shards?
A critical look at Redis, outlining some things to watch out for when running large Redis instances, making the case for many smaller instances instead.
January 18, 2013
Calculating Velocity Scores at the Speed of Redis
To really get a feel for a technology, you have to at least build a proof of concept application using it. Building a simple application that uses Redis as an in memory hash table isn't very interesting, so I was searching for something that would test some of the more advanced features of Redis.
January 17, 2013
A Quick Overview Of Redis
Redis has gotten a lot of positive hype over the last few years, so I decided to make it the first NoSQL database I would investigate.
January 10, 2013
Connecting to Sybase from Java with the JTDS drivers
A short piece of Java code to connect to Java from Sybase
December 19, 2012
Installing the libv8 Ruby gem on Centos 5.8
How to install the Ruby libv8 gem on Centos 5.8 without (much) pain
December 17, 2012
Ruby 1.9.3 libyaml centos 5.6
How to get Ruby installed so that gem, irb etc do not complain about missing psych and libyaml.
October 07, 2012
DBGeni - Better database installs
My first complete side-project, the Database Generic Installer - DBGeni. It is a Ruby gem that applies changes to databases using migration scripts.
May 22, 2012
Oracle JDBC connections slow to connect /dev/urandom
This little workaround can solve a problem when JDBC connection to Oracle are slow to establish.
November 16, 2011
Connecting to Sybase with JRuby using the jtds drivers
A simple method to make JDBC connections to Sybase using JRuby
October 19, 2011
Installing ruby-oci8 on 64 bit Windows
Solving the error OCI.DLL: 193 is not a valid Win32 application when installing ruby-oci8
September 20, 2011
On getting stuff done in companies
Interesting Hacker News comment on the topic of how to hire people who get stuff done
December 23, 2010
Achievements in 2010
A quick list of what I achieved in 2010. Probably not of interest to many people, but it was worth writing for my own benefit.
December 08, 2010
A few general emacs tips
Finishing up the series on Emacs, this post points out a few tips and tricks I have learned working in it for the past few years.
November 30, 2010
Rails options for Emacs
How to configure emacs with some Rails specific IDE modes, however the simple solution may be good enough for most people.
November 29, 2010
Emacs Ruby Foo
Before worrying about Rails, you need to get Emacs to behave sanely with Ruby code. That means it should indent it automatically and syntax highlight the code. This post will guide you on getting ruby-mode working nicely.
November 28, 2010
Setting up the emacs code browser
This post continues the series on setting up emacs, this time focusing on installing, configuring and using the emacs code browser (ecb).
November 28, 2010
Installing Emacs on Windows and OS X
The second post in a series about setting Emacs up for Ruby on Rails development. This post explains how to get Emacs installed on Windows and OS X.
November 28, 2010
Choosing a text editor for Rails development
The first post in a series about setting up Emacs, primarily for Ruby on Rails development. This post discusses the reasons for choosing Emacs and the goals of the tutorial.
November 24, 2010
Sell Yourself
If your 10th App has failed, and your money is running out, and you need to go get a job, then it would be good to have something to point to that shows off the skills you have learned...
November 23, 2010
The new blog is ready
Well, another new blog. Hopefully I will stick with it longer than the last two, where I pretty much ran out of steam after only a few posts ...
