Cassandra-notes

Cassandra is a distributed database management system designed for handling a high volume of structured data across commodity servers.

Cassandra’s design criteria:

• Distributed: Runs on more than one server node.
• Scale linearly: By adding nodes, not more hardware on existing nodes.
• Work globally: A cluster may be geographically distributed.
• Favor writes over reads: Writes are an order of magnitude faster than reads.
• Democratic peer to peer architecture: No master/slave.
• Favor partition tolerance and availability over consistency: Eventually consistent (see the CAP theorem: Here)
• Support fast targeted reads by primary key: Focus on primary key reads alternative paths are very sub-optimal.
• Support data with a defined lifetime: All data in a Cassandra database has a defined lifetime no need to delete it after the lifetime expires the data goes away.

Ideal Cassandra Use Cases:

• The ideal Cassandra application has the following characteristics:

  • Writes exceed reads by a large margin.
  • Data is rarely updated and when updates are made they are idempotent.
  • Read Access is by a known primary key.
  • Data can be partitioned via a key that allows the database to be spread evenly across multiple nodes.
  • There is no need for joins or aggregates.

• Some of my favorite examples of good use cases for Cassandra are:

  • Transaction logging: Purchases, test scores, movies watched and movie latest location.
  • Storing time series data (as long as you do your own aggregates).
  • Tracking pretty much anything including order status, packages etc.
  • Storing health tracker data.
  • Weather service history.
  • Internet of things status and event history.
  • Telematics: IOT for cars and trucks.
  • Email envelopes—not the contents.

spring boot data cassandra example

create keyspace

create keyspace testcass with replication={'class':'SimpleStrategy', 'replication_factor':1}
CREATE TABLE customer(
   id timeuuid PRIMARY KEY,
   name text,
   age int,
   active boolean
);