Cassandra is an open-source distributed NoSQL database developed at Facebook that provides high availability without a single point of failure. It uses a distributed key-value and column-oriented data model and is well-suited for applications that need to store and retrieve large amounts of structured and unstructured data quickly. Cassandra offers benefits like scalability, fault tolerance and load balancing but lacks features like revision history and does not support relational data structures or individual fields over a certain size. It exposes metrics through JMX and can be accessed using Thrift from any programming language including PHP via frameworks like phpcassa and Pandra.

1. The Myth of Cassandra I’ve had it with these crazed oracles NoSQL Series Cameron Kilgore | @thrillgore

2. Cas·san·dra[kəˈsændrə], noun [Classical Greek Mythology.] A daughter of Priam and Hecuba, a prophet cursed by Apollo so that her prophecies, though true, were fated never to be believed. [fml. “Apache Cassandra”] An open-source distributed, non-relational (NoSQL) database developed at Facebook, written in Java, and maintained as an Apache Software Foundation product

3. What Cassandra does Nonrelational associative array (key-value) data storage Distributed One-hop DHT (akin to Amazon Dynamo) Eventually Consistent Column-based storage Queries faster than MySQL Based on white papers and real-world use cases Fault tolerant Provides no single point of failure Load balancing

4. What Cassandra Does Not Revision History Relational Data There’s this thing called “MySQL” that might be just up your alley Provide an admin app Chiton is an in-development desktop app http://github.com/driftx/chiton Store individual data fields greater than 231-1 (2,147,483,647) bytes Provide any interfaces outside of Thrift or high-level interfaces

5. She who entangles companies Already at use at Facebook Also being used at: Digg Reddit Twitter Rackspace Cisco IBM Cloudkick OpenX And more…

6. Introducing Cassandra Understanding the concepts of data in Cassandra, scalability

7. Columns and Data Data is stored in columns, each organized by keyspaces Each column stores data and can be culled based on its name value, akin to an associative array +name: byte[] +value: byte[] +timestamp: long

8. Supercolumns What happens when Xzibit uses Cassandra Supercolumns allow you to nest n number of columns in another column And in return in a key you can nest n number of supercolumns. (not shown here due to Office fail)

9. Anatomy of a Column Cassandra is written in Java, so we abide by the rules of its variables Most of them will be bytestrings (byte[]), set in Unicode +time being the only value not stored as a bytestring, instead as a long Java compares the +time across other Cassandra nodes to reconcile data across nodes Is NOT used for revision history Each column represented by an unseen UUID

10. Anatomy of a Column (cont.) Columns are found by their +name value, not their UUID You cannot have multiple columns of the same name (assigning one with the same name rewrites an existing one in that given keyspace)

11. Accessing the Data Data accessed through the Apache Incubator™ Thrift API Thrift can be accessed with any programming language or application High-level implementations for languages exist For our demos we’re going to use the cassandra-cli client, which gives us the ability to insert/remove/edit

12. <INSERT CALL TO DEMO HERE> OH GOD HOW DID I GET HERE I AM NOT GOOD WITH COMPUTER

13. Security in Cassandra Cassandra does have user authentication through a SimpleAuthenticator module that is configured in conf files Very rudimentary Ran out of time and suitable documentation to demonstrate it Cassandra is not ACID-compliant

14. Load Balancing Cassandra 0.6 has load balancing capabilities Not automatic, must be configured per node Load is shared in a token-ring fashion across the nodes in a multi-node configuration Covered in the documentation for Cassandra

15. Monitoring Cassandra Cassandra exposes metrics as JMX data, so any JMX monitoring app should be sufficient. Nagios Munin OpenNMS Any official Oracle™ Java monitoring and administration software What? I can’t be bothered to not search for the name of the software? Cassandra also has software for monitoring node activity, check the docs

16. Use Case Example And a very simple one at that

17. Product Ordering Application An ordering application implemented using a SQL database could span hundreds of tables and require constant iterations over its lifespan What if the attributes of these products (in this case, HVAC components) were stored in Cassandra, and we kept pricing, users, and sessions data in a RDBMS?

18. Benefits to Cassandra The data for these products that might need to be added won’t require new RDBMS fields – we can just add them in new columns and write our code statements to ignore them if they aren’t there We aren’t limited to bottlenecks in the RDBMS if we choose to go multinode in our Cassandra setup No single point of failure if we choose to go multinode If we get a lot of users (unlikely), the nodes will equally distribute the load Less time spent on queries Depends on how effective our data is stored and the performance of our application

19. Downsides to Cassandra We may not have the funding needed to procure a multinode configuration No guarantee that existing data that might need to be reconfigured might be changed over time to meet the demands of sales, engineering, executive, etc. Data collected and given some form of relation inside the application itself, with no schema Cassandra lacks a vetted security framework that could put us at risk Cassandra also lacks a complete administration application Chiton is barely functional as-is Might not make sense when some RDBMS can scale across machines

20. A (crude) data map showing our data in practice

21. Cassandra and PHP This is a PHP User group after all.

22. Talking to Cassandra Low-level framework, Thrift, is the actual client API for Cassandra In PHP we have two such frameworks that work through Thrift phpcassa Pandra Ran out of time to prepare a demo There’s always another time for a demo. Stay tuned.

23. Any Questions? You will be baked, and there will be cake