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NoSQL (12 posts)


HBase - scan options

Scan is the second way to get data from HBase tables and in this post I'll show a simple example using java, showing some options like Start, Stop row and batching. (read more...)


HBase/Java error reduce flushing

During the excuting a map and reduce of Hadoop Java job the reduce felt down, returning this error_get_last. (read more...)


HBase/Java migration to 1.1.2

There are several changes when migrating from HBase 0.98 to 1.1.2 and in case of using method java to interface to it, we have to consider to modify in this way. (read more...)


HBase - Shell

In this post I'll show some tips and tricks using the Hbase shell. The post will be updated when I'll find new interesting commands. (read more...)


Spark - Join with lists

The Join function doesn't work with list, so to make a merge of them we will create two RDDs for each list. Before starting to read this post, you need to read (read more...)


Spark - Difference Map and flatMap

In this post I'll show the difference between Map and FlatMap, that work quite differently when it comes to lists. Note before starting to read this post, you need to read (read more...)


Spark - example of Distinct

Before starting to read this post, you need to read this where there is the quickly introduction to some PySpark functions. In this post I'll show the difference using or not the distinct function. (read more...)


Spark - Map, Reduce and Filter

In this first post about Spark, I'll show some examples using the PySpark Map function join with Reduce, ReduceByKey and Filter, in order to produce the new RDDs and finally the output. (read more...)


MongoDB - Replication and rollback

One of the test exams to get the MongoDB Developer certification was about the Replication. The scenary was three node running (read more...)


MongoDB - Ordinal number array

I have this structure that figure out the blog's posts and its likes to the comments. (read more...)


MongoDB - Exceed memory

A test of the MongoDb Developer's exams was to use the aggregation to figure out pairs of people that tend to communicate a lot from a dataset where is a very large numbers of the email. (read more...)


MongoDB - Aggragate cases

One of the tests of the MongoDB Developer Course was the aggregation framework and these three exercises and my solution. I'm trying to explain every steps for each one of them. (read more...)