(7) Scalability and Complexity Analysis. Fig. 1 shows the NoSQL Scalability Complexity relationship. As shown in the figure Key-value NoSQL are suitable for data intensive applications, while the Graph databases (Non Aggregate) NoSQL are best fit for applications dealing with complex data. It is also evident from the figure that, the Document (Aggregate oriented) NoSQL is the most suitable NoSQL databases having a good balance of ‘‘Data Complexity’’ and ‘‘Data Size’’. Since 90% of use cases are much below the ‘‘Data Size’’ supported by the entire NoSQL database, still most of the application is perfectly running with conventional RDBMS.
(8) NRW Analysis.
NRW (Node, Read, Write) analysis is used to analyze the characteristics of distributed database how they will trade off Consistency, Read and Write performance .
Here,
N is the number of Nodes keeping copies of distributed record;
W, number of nodes that must successfully acknowledge for a Write to be successfully committed.
R, the number of nodes that must send back the data to be accepted as read by the system.
The majority of NoSQL databases uses N > W > 1 i.e. more
than one write must complete, but not all nodes need to be updated
immediately.
Tables 4 and 5 categorize the NoSQL according to NRW .
The ‘‘Read Repair’’ algorithm is often implemented to improve consistency when R = 1.
The following are some more muscle with various Consistency levels .