My name is Kerneels. I write, code and partner with people to build software systems that are good and fast. Solutions at good fast dot info is where you can reach me.

This is my site where I write about anything that interests me. And so, I present to you, the method and the madness; a window into my mind!

Recent Posts

How to use the transitive closure over a set of relations for fast path finding in SQL

published on
In a previous post, I wrote about how we make sense of the world by modelling relationships between things as tree-like hierarchies. This time we will add to this hierarchical data structure, a representation derived by calculating all possible paths. This set of paths is referred to as a transitive closure, and can be thought of as the set of all paths if you start at each node in the tree. Read More...

Wizen up a bit : solve problems bitwize

published on
I’m rather obsessed with bits. All sorts of bits, at various times, but in particular, the digital bit of the Binary system. Notice the capitalization of “Binary” - it is intended. Efficient bit representations of information is purity ; ever more compact representations elegance itself, so for this post I invite you to come with me, way back to 2013, when a nice couple of bitwise operations flaunted their power and expressiveness. Read More...

10 Ways to outsmart cyber criminals

published on
Big day; our first guest contribution! Johann Bergh, a professional translator and recovering software developer put together this list of 10 ways how you can be proactive and outsmart cyber criminals. Enjoy, and take action! Information is key to the success of cyber criminals. It is the driver that enables them to destroy, steal and extort. Cyber criminals are great detectives. They unite scraps of information from various sources into a nefarious plan. Read More...

Speed up slow views through custom materialization

published on
SQL views are aluring as a means of abstraction; a “building block” to hide away commonly used complexity. It is no wonder then that us developers will try them out, and before you know it, your clever recursive CTE view on that hierarchy is used everywhere, by everyone, but how is it affecting overall database performance… They look like tables, can be joined on, selected from, and in some cases even updated just like tables, yet the reality is that they are not like tables. Read More...

Knapsack Bitwise

published on
An interesting bit of computer science, the knapsack problem has been studied for over a century, and according to Wikipedia, seems to be quite popular - as these sort of things go. For the first post in this series I’ll present a solution to the 1⁄0, or binary version of this famous problem I designed in 2015. I was immediately intrigued by it when I first read the problem statement. It’s application to anything requireing optimal resource allocation was very clear, and my mind started obsessively thinking of how to solve this efficiently. Read More...

CTE : simplify those nested sub queries

published on
This article examines how sub queries can be substituted for the far more readable common table expressions, or CTEs available in many RDBMS systems. I was motivated to write this article when a friend who is fairly new to SQL expressed difficulty in grasping queries containing nested sub queries. If you’ve never heard of CTEs before and you want to get the most out of this article, I recommend you get AdventureWorks2014 sample database and experiment a little with the queries below. Read More...

Efficient git command line & reasonable workflo

published on
Owning a software development shop, or being the prolific master coder that you are, what would you say is your most valuable assit? Is it your carefully acquired intellectual capital in the form of your people / your awesome self? Is it your revolutionary, novel ideas? Perhaps it’s both of those, in some sense, but how about something more mundane, like the great code written in the last hour, or day or months? Read More...

now make it fast

published on
“He began to copy one of our tables, which contained partial user information, including email IDs, hashed passwords, and last tested URL. His copy operation locked the database table, which raised alerts on our monitoring system. On receiving the alerts, we checked the logs, saw an unrecognized IP, and blocked it right away. In that time, the hacker had been able to retrieve only a portion of the data.” – From the postmortem of the Browser Stack hack of 9th November, 2014 at 23:30 GMT Since relational database management systems (RDBMS) have been used in production environments since 1970 (Micro DBMS), and the theory on which they run was developed in the preceding decade,and perfected in the three remaining decades of the previous century (long ago), it was not surprising that, as a subject, it received very little attention in our curriculum - at least where I studied. Read More...


Algorithms (1)

Best-Practice (1)

Bitwise (1)

C# (2)

Code-Contest (1)

Complexity (1)

Computer-Science (1)

Cyber-Security (1)

Database (3)

Hierarchies (1)

Minimalism (1)

Optimisation (2)

Optimization (1)

Performance (4)

Privacy (1)

Procedures (3)

Readability (1)

Simplification (2)

Source-Control (1)

Sql (3)

T-Sql (4)

Transativity (1)

Version-Control (1)

Workflow (1)


algorithms (1) alias (1) bash (1) bitwise-operators (1) brute-force (1) c# (1) cartesian-join (1) clustered-index (1) cte (1) cyber-security (1) full-join (1) git (1) heaps (1) knapsack-problem (1) malware (1) merge (1) nonclustered-index (1) online-presence (1) physical-layout (1) privacy (1) rebase (1) recursive-cte (1) security-patches (1) social-media (1) stored-procedure (1) sub-query (1) tdd (1) trigger (1) view (1)