The data knowledge stack

Concurrency is not for the faint-hearted We all know concurrency programming is difficult to get it right. That’s why threading tasks are followed by extensive design and code review sessions. You never assign concurrent issues to inexperienced developers. The problem space is carefully analyzed, a design emerges and the solution is both documented and reviewed. That’s how threading related tasks are usually addressed. You will naturally choose a higher level abstraction since you don’t want to get tangled up in low-level details. That’s why the java.util.concurrent is usually better (unless you build… Read More

The simple scalability equation

Queuing Theory The queueing theory allows us to predict queue lengths and waiting times, which is of paramount importance for capacity planning. For an architect, this is a very handy tool since queues are not just the appanage of messaging systems. To avoid system over loading we use throttling. Whenever the number of incoming requests surpasses the available resources, we basically have two options: discarding all overflowing traffic, therefore decreasing availability queuing requests and wait (for as long as a time out threshold) for busy resources to become available This behavior applies… Read More

Time to break free from the SQL-92 mindset

Are you stuck in the 90s? If you are only using the SQL-92 language reference, then you are overlooking so many great features like: Window Functions PIVOT MERGE INSTEAD OF triggers Some test data In my previous article I imported some CSV Dropwizard metrics into PostgreSQL for further analysis.

How to import CSV data into PostgreSQL

Introduction Many database servers support CSV data transfers and this post will show one way you can import CSV files to PostgreSQL. SQL aggregation rocks! My previous post demonstrated FlexyPool metrics capabilities and all connection related statistics were exported in CSV format. When it comes to aggregation tabular data SQL is at its best. If your database engine supports SQL:2003 windows functions you should definitely make use of this great feature.

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