The tango between Hive and Impala
An interesting tango exists between Hive and Impala. The situation is as follows. Hive acts as an layer upon map reduce. It provides an interface whereby table definitions can be […]
Joining files by Pig
In the previous post, we used scala to merge two files. The interesting feature is that scala bypasses Mapreduce. Pig uses Mapreduce. If we undertake the same example, we will […]
Joining files by Scala
In this note, I will provide another script to join two files. The files are foo and bar. They contain lines whereby the elements are separated by a bar (|). […]
Flume used for logs
In an earlier post, I showed how one may send a stream via netcat to hdfs using flume. Another possibility is to set up a stream that is received by […]
Datamodelling in Hadoop
Before data modelling in Hadoop can be discussed, one needs to realise that Hadoop is about files. It is not about tables and relations – it is the files that […]
HBase
HBase is a database system that is built on top of HDFS. However the term ‘database’ might be a bit misleading. It is not a traditional SQL database that can […]
Write an AVRO file
Below, I provide some Python code to write an AVRO file. An AVRO file consists of a scheme and a set of records. The records are written in binary format. […]
Copying content of an Oracle table into an avro file
Below, you will find a listing on how to copy the content of an Oracle table into an avro file. The trick is quite straight forward. A table is read […]
Sending Avro file via HTTP
It is possible to send an AVRO file via HTTP. The idea is that one sets up a server process. Once the server process runs, a client call is made. […]
Show content of an AVRO file with Python
This note describes how we can show the content of an AVRO file with Python. We use python3 as tool here. We use this from an Anaconda framework. I checked […]