Apache Gora over HBase

Question

We are planning to implement data warehouse based on HBase.

There are multiple entities which has Parent child like relation or in other words we have nesting.

public class Parent {

private String name;

private List<Dependent> dependents;
...
}

As per HBase, we can store these nested entities as value [as json / avro] in one of columnFamily.

We are looking at Phoenix for real time querying, I came across Apache Gora as one of the option. As per documentation Apache Gora provides a nested entities but there is limited examples & documentation.

Does anyone have examples or experience with Apache Gora over HBase

Answer 1

I have some development notes at http://people.apache.org/~alfonsonishikawa/gora-174.html and http://people.apache.org/~alfonsonishikawa/gora-174-notes.html (sorry if they are not very clarifying).

First of all, if I am not wrong, Apache Gora is not integrated into Apache Phoenix and I believe your necessities will not be covered.

Anyway, about your question regarding nested entities, Gora serializes de dependent entity and puts it into a column. When you have a List/Array of dependents like in your example, each dependent entity goes into a column of a family. The negerated column name is the index. When you have a Map of dependets, each entity goes into a column of a family, and the column name is the key of the dependent entity in the map.

Additionally, The fact that de data is serialized implies that you can't query on their content.

I hope this resolve your doubts, but if you have any other question just ask it :)