Throughout my life, I lost track of things I wanted to learn. I have a forever-growing list of books I want to read on Good Reads, many of them related to Computer Science somehow. As I make a living by building software, I decided to have a dedicated number of hours a week to study… Continue reading My Study Plans
Words about Idempotency
The other day I came across this article. I was immediately interested in it since we are designing a system that needs idempotency and didn’t have anything in place. The nice thing about Airbnb’s design was that they generalized the idempotency with a three-phase process. Pre-RPC, RPC, and Post-RPC. In the first phase, they record… Continue reading Words about Idempotency
Chapter 11: Stream Processing
This chapter discusses the purpose of event streams, how to process them, and some key differences between them and batch processing. Message brokers process event streams, and there are two types of them: The first one is AMQP/JMS-style message brokers, which is suitable when there is no need to go back in time to reprocess… Continue reading Chapter 11: Stream Processing
Chapter 10: Batch processing
This chapter starts by discussing Unix tools and pipes and how they are composed to solve larger problems. Later, the same principles are derived to explain how MapReduce and other more recent dataflow engines work. The pipe is the main driver of data between two Unix processes. On MapReduce, on the other hand, are files… Continue reading Chapter 10: Batch processing
Chapter 9: Consistency and Consensus
This chapter, as the title says, touches on both consistency and consensus from different angles. The first concept it dishes out is about linearizability, a consistency model that tries to make all the data behave as if it is written sequentially. A weaker consistency model can be model using the concept of casualty, which differs… Continue reading Chapter 9: Consistency and Consensus
Compilers – Java: my study notes
These notes are from the Week 10 of the Compilers course by Stanford. Arrays One problem that Java arrays resolve lies in inheritance. If we have classes A and B which B inherits from A the relationship would still be valid for B[] < A[]. The problem would happen with the following code: class A { }… Continue reading Compilers – Java: my study notes
Compilers – Register Allocation and Garbage Collection: my study notes
These notes are from the Week 9 of the Compilers course by Stanford. Register Allocation When we generate intermediate code, we are not concerned about how many registers the target machine has. Therefore, the last phase should allocate variables in registers and also have a backup plan when more variables need to be allocated at any given… Continue reading Compilers – Register Allocation and Garbage Collection: my study notes
Chapter 8: The Trouble with Distributed Systems
In distributed systems, things will be wrong and the systems engineers should be creating mechanisms to avoid that a failure in components affects the whole availability of the system. We should build reliable systems from unreliable components, but there are some limitations on how reliable a system can be. Network Problems One failure is due… Continue reading Chapter 8: The Trouble with Distributed Systems
Compilers – Local Optimization & Global Optimization: my study notes
These notes are from the Week 8 of the Compilers course by Stanford. An intermediate language provides an intermediate level of abstraction while compiling languages, helping optimizations by including more details than the source language has, but not as much as the target language. Code optimization is usually done before code generation in intermediate code, to avoid… Continue reading Compilers – Local Optimization & Global Optimization: my study notes
Compilers – Code Generation & Operational Semantics: my study notes
These notes are from the Week 7 of the Compilers course by Stanford. This focuses on the discussion about code generation. The architecture chosen for this class is a Stack Machine architecture on top of the MIPS architecture. Code Generation The MIPS processor supports the following instructions: lw reg1 offset reg2: Load a 32-bit word from the address… Continue reading Compilers – Code Generation & Operational Semantics: my study notes
Chapter 7: Transactions
Many things can go wrong with systems, such as: The software or hardware might fail at the middle of an operation Network failures can cause unexpected cut offs in the application Multiple clients might write at the same time causing overwrites Reads might return incomplete writes For decades, transactions are the way databases implemented mechanisms… Continue reading Chapter 7: Transactions