The First Cry of Atom Today is the first day of the rest of my life.

Join StackOverflow

As you know StackOverflow is the most famous Q&A site for especially programming and software. You can ask any type of programming questions or search it. There are no software engineers who do not use this site in their daily development, I think. Of course I am also a heavy user of StackOverflow. When I have faced a problem in my develo... Read more

Random Walk of Stock Value

I’ve read a book about financial mathematical model used in Wall Street. This book describes about the people who invented the financial models which become state-of-the-art technologies nowadays. I’m not familiar with finance detail but the book was very interesting. The models introduced in this book was simple. So I want to write a tiny pr... Read more

About BlinkDB

Today I found a interesting commit in Presto project. Remove support for approximate queries What is approximate queries? Why do we use approximate queries? The idea was originally developed in BlinkDB. According to the official website of BlinkDB, it’s called approximate query engine. BlinkDB is a massively parallel, approximate query en... Read more

Tuning G1 GC algorithm on JVM

Recently I faced the necessity to tune garbage collection of our Java application. The application is Presto , distributed query execution engine. It requires a lot of memory but needs to achieve high throughput and low latency. So I read a book about tuning Java applications. Since Presto uses G1 GC algorithm, I want to summarize how to tune... Read more

Hivemall is now Apache Incubator!

Today I have a big news. Now Hivemall joined Apache incubator project! Hivemall is a scalable machine learning library running on Hadoop. It was originally developed by Yui Makoto who is a research engineer at Treasure Data Inc. So from now, we call it Apache Hivemall. Top page is now opened. Apache Hivemall is developed as Hive UDF. Therefor... Read more