blog.timmattison.com
mostly tech
Mini Hack: Parallel vacuuming in PostgreSQL
I run several development environments that I need to sync with production databases to do bug fixes and new feature development. It’s always good to vacuum these databases before using them especially if you’re doing it via rsync on a live system. If you don’t you could end up with rows that are inaccessible from [...]
How-To: Set up multi-head X in Debian using Nvidia cards
I just had to set up a multi-head system in Debian and it consumed way too much of my time. I did see a lot of articles about it online but they all had a few common threads. First, they all mentioned Xinerama was deprecated which initially scared me off of it. Xinerama is deprecated [...]
How-To: Find and fix duplicate Java object serial numbers
In Java making your objects serializable is often required to work with certain libraries (ORM, GWT-RPC, etc). It’s tempting when Eclipse tells us that our object is missing a unique identifier to have it generate one on the fly. However, in practice what happens sometimes in the field is that you’ll create a serializable class [...]
Mini hack: Approximating the size of a Java object
Finding the size of an object or data structure used to be simple in “the good old days”. You could just use the sizeof function and it’d spit out something that usually made sense. In Java there’s nothing that seems to do it quite that simply. I’ve seen some solutions that involve using Java instrumentation [...]
How-To: Disable HDFS permissions for Hadoop development
If you’ve set up Hadoop for development you may be wondering why you can’t read or write files or create MapReduce jobs then you’re probably missing a tiny bit of configuration. For most development systems in pseudo-distributed mode it’s easiest to disable permissions altogether. This means that any user, not just the “hdfs” user, can [...]
How-To: Install Hadoop on Debian/Ubuntu
Yesterday I passed my Cloudera Certified Hadoop Developer (CCHD) certification. The four day class was great and I learned a lot about everything from the architecture of HDFS all the way to specific MapReduce algorithms and how to implement them using Hadoop. I’m excited about implementing this in my companies as we’re already using a [...]
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