The First Cry of Atom

How to reindex Elasticsearch

Due to the nature of the database system, the schema definition should be evolved as time goes by. We may need to add the type information for new columns, change the name of the same attribute. Otherwise, the database would not be able to deliver the value expected by users. The evolution of database schema is inevitable factor in the context o... Read more

YouTube to Learn Science

Recently, I found that YouTube was an excellent resource to learn new things. As MOOCs emerged as a platform for education, YouTube is also gaining popularity as a place to learn many things which are traditionally taught in the school. A well-designed movie gives us a chance to understand the complicated notion of intuitively. When I was in sch... Read more

First Ever Presto Conference in Tokyo

In the last month, we have held a Presto conference in Tokyo at our office. That is the first-ever Presto conference gathering Presto developers in the Japanese community. While I’ve written a report in the official blog of, I neglected to write down my thought on this blog. This is the article to describe the impression I had a... Read more

Inspect Presto connection with Charles

Seeing the unseen is the fundamental principle in debugging for software. The exchange of data between processes through the network is not visible literally. We often encountered the case when we need to inspect the data transmitted between multiple processes for debugging. SSL/TLS connection is one of the famous examples where it is difficult... Read more

Bitshift to 64 bit in Java

Bitwise operation sometimes looks like magic. There is a bunch of sophisticated techniques to manipulate the value at the bit level. Bit shift operation is one of these operations. You can shift the bit sequence of the given value by using shift operators which are commonly described as >> or << in many programming languages. But do ... Read more