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Category: programming

Multi-column data plotting with Gnuplot

In my previous post I showed how to generate good looking charts with Gnuplot. Those were simple bar charts with a single bar. In this post I want to show you how to plot bar charts with multiple bars. Such charts take multiple columns of data and plot them grouped in the chart. We'll be working with […]

Generating good-looking charts with Gnuplot

Gnuplot is a tool for plotting graphs. It was originally created to allow scientists and students to visualize mathematical functions and data interactively, but has grown to support many non-interactive uses such as web scripting. It is excellent for generating all kinds of charts. Unfortunately, the defaults for Gnuplot don't generate very appealing charts: set terminal […]

Various databases and how they scale

By chance I stumbled upon an article about databases and how they scale. It's a great read and does an excellent job describing the various stengths and weaknesses regarding different kinds of scaling for databases. Especially the images really capture the essence. 

Test a pull / merge request before accepting on Bitbucket

Git is a great tool, but its documentation leaves much to be desired at times. Bitbucket's documentation doesn't fare much better. Commands mentioned in its wiki often don't work as advertised. The fact that git's commands are often incredibly counter-intuitive, incomplete and at times simply wrong doesn't help either. So while you can get far […]

bbcloner v1.3 released. BitBucket backup tool.

I've just released bbcloner v1.3. bbcloner creates mirrors of your public and private Bitbucket Git repositories and wikis. It also synchronizes already existing mirrors. Initial mirror setup requires you manually enter your username/password. Subsequent synchronization of mirrors is done using Deployment Keys. This release features the following changes: Support for updating over https (patch by msboom) […]

my_indexr: Script to drop and recreate MySQL indexes

As can be read in this article, I was in need of a method to quickly drop all indexes (except primary keys) from a MySQL database. After googling around a bit and being astonished that apparently no-one had written such a thing yet, I wrote the script that can be seen in that article. Unfortunately, […]

Think Bayes: Bayesian Statistics in Python

There's a free download available of "Think Bayes – Bayesian Statistics in Python" over at it-ebooks.info. A small excerpt from the book: The premise of this book, and the other books in the Think X series, is that if you know how to program, you can use that skill to learn other topics. Most books […]

Increasing performance of bulk updates of large tables in MySQL

I recently had to perform some bulk updates on semi-large tables (3 to 7 million rows) in MySQL. I ran into various problems that negatively affected the performance on these updates. In this blog post I will outline the problems I ran into and how I solved them. Eventually I managed to increase the performance […]

Quick-n-dirty HAR (HTTP Archive) viewer

HAR, HTTP Archive, is a JSON-encoded dump of a list of requests and their associated headers, bodies, etc. Here's a partial example containing a single request: { "startedDateTime": "2013-09-16T18:02:04.741Z", "time": 51, "request": { "method": "GET", "url": "http://electricmonk.nl/", "httpVersion": "HTTP/1.1", "headers": [], "queryString": [], "cookies": [], "headersSize": 38, "bodySize": 0 }, "response": { "status": 301, "statusText": […]

bbcloner: create mirrors of your public and private Bitbucket Git repositories

  I wrote a small tool that assists in creating mirrors of your public and private Bitbucket Git repositories and wikis. It also synchronizes already existing mirrors. Initial mirror setup requires that you manually enter your username/password. Subsequent synchronization of mirrors is done using Deployment Keys. You can download a tar.gz, a Debian/Ubuntu package or clone […]