Elasticsearch as an index store

Elasticseach can be used to store indexes of NoSQL database to perform faster aggregations.

Kundera supported NoSQL databases that can leverage Elasticsearch as an indexing store:

• Cassandra
• Hbase
• MongoDB
• CouchDB
• Oracle NoSQL
• Redis

Note: Along with client dependency, Kundera-elastic-search dependency will be needed.

##How to use

Step 1

In persistence.xml of a specific client, user needs to add the following -

<property name="kundera.indexer.class" value="com.impetus.client.es.index.ESIndexer"/>

Step 2

Add esindexer.xml file in classpath.

Step 3

Specify the fields with @IndexCollection annotation on which indexes are created.

Example:

@IndexCollection(columns = { @com.impetus.kundera.index.Index(name = "price") })
public class Product
{
     @Column(name = "Price")
     private int price;
}

All set for strong indexes in Elasticsearch.

##Aggregation on NoSQL data using Kundera Elasticsearch

How to perform aggregation over data stored in NoSQL?