The First Cry of Atom

Serialization of Java sometimes complex and difficult to understand for me. I’ve read Effective Java and javadoc of JDK SE api docs. So I knew I understood the basic concept of serialization of Java object. But I have faced to a problem when I wrote Hive UDAF. This might be... [Read More]

I’ve finished reading this book. Though this is written in English originally, I read the translated version. [Read More]

As described here, we cannot run Presto package build on OSX. Mainly it was caused by JNI side issue and machine architecture. I knew the issue from Issue 3849. [Read More]

Recently I’m getting started using Presto. This is a distributed SQL query engine like Hive. I’m working on Hadoop, Hive until now. So I have though there are a lot of similarity between Hive and Presto. This is almost true in terms of user interface and SQL syntax. But Presto... [Read More]

histogram_numeric is a UDAF which should calculate the distribution of given records. But at the same time it should generate a table that represents one category by one row. In this point we can regard this type of UDF is a combination of UDAF and UDTF. For example the output... [Read More]