Joao Junior

Redis is an in-memory data structure store, very powerful, with an excellent abstraction via its API to manipulate its data structure. What makes Redis very powerful, in my opinion, is the variety of data structures it provides and the performance of its operations. This last feature is an effect of being an in-memory store. As with every software, Redis also has technical decisions and limitations that we need to be aware of and consider when choosing it. [Read More]

I was verifying the performance of an endpoint in an API using framegraph when I noticed that checking if an object is in a set or a hash data structure was consuming a lot of time. This post explains the problem and the solution to it. First of all, checking if an object is in a Set or HashMap is O(1) when we don’t consider collisions. Even in the presence of collisions, it should be much less than O(n), where n is the number of items in the set. [Read More]

First things first, this is a classic book by Tom DeMarco and Timothy Lister that everyone working in the software industry must read. The third edition divides this book into 6 parts with 39 chapters and 249 pages. It is an easy book to read and follow. However, it is necessary to stop constantly to reflect on the facts and ideas presented. Also, the reading would be like a map of the industry if you had a lot of experience in the software development industry. [Read More]

When we study transactions in relational databases, one of the first things we learn are the guarantees that a transaction must provide. ACID(Atomicity, Consistency, Isolation, Durability) are the properties that we desire. Here, I will discuss the Isolation level in more detail and show that atomicity alone is not enough when handling concurrency. One classic example of the importance of atomicity is moving money between accounts. So, imagine that we have two accounts and we would like to transfer the total amount from one account to another one. [Read More]