A few weeks back one of the Vertica developers put up a blog post on counting triangles in an undirected graph with reciprocal edges. The author was comparing the size of the data and the elapsed times to run this calculation on Hadoop and Vertica and put up the work on github and encouraged...
You’ve probably heard sayings like “sometimes things aren’t always what they seem” and “people lie”. Well, sometimes execution plans lie. It’s not really by intent, but it is sometimes difficult (or impossible) to represent everything in a query execution tree in nice tabular format like dbms_xplan gives. One of the optimizations that was introduced...
Leveraging Oracle’s Parallel Execution (PX) in your Oracle data warehouse is probably the most important feature/technology one can use to speed up operations on large data sets. PX is not, however, “go fast” magic pixi dust for any old operation (if thats what you think, you probably don’t understand the parallel...
A number of weeks back I had come across a paper/presentation by Riyaj Shamsudeen entitled Battle of the Nodes: RAC Performance Myths (avaiable here). As I was looking through it I saw one example that struck me as very odd (Myth #3 – Interconnect Performance) and I contacted him about it. After further review...