Short overview of Apache Cassandra: features and benefits, use cases, architecture, CQL, data objects, etc.

1. Apache Cassandra
overview
by Taras Tymoshchuk, software developer at ElifTech

2. Introduction
What is Apache Cassandra?
Apache Cassandra™ is a free
Distributed…
High performance…
Extremely scalable…
Fault tolerant (i.e. no single point of failure)…
post-relational database solution. Cassandra can serve as both
real-time datastore (the “system of record”) for
online/transactional applications, and as a read-intensive
database for business intelligence systems.

3. Top Use Cases
● Internet of things applications – Cassandra is perfect for consuming lots of fast
incoming data from devices, sensors and similar mechanisms that exist in many
different locations.
● Product catalogs and retail apps – Cassandra is the database of choice for many
retailers that need durable shopping cart protection, fast product catalog input and
lookups, and similar retail app support.
● User activity tracking and monitoring – many media and entertainment companies
use Cassandra to track and monitor the activity of their users’ interactions with their
movies, music, website and online applications.
● Messaging – Cassandra serves as the database backbone for numerous mobile
phone and messaging providers’ applications.
● Social media analytics and recommendation engines – many online companies,
websites, and social media providers use Cassandra to ingest, analyze, and provide
analysis and recommendations to their customers.

4. Key Cassandra Features and Benefits
● Gigabyte to Petabyte scalability
● Linear performance
● No SPOF
● Easy replication / data distribution
● Multi datacenter and cloud capable
● No need for separate caching layer
● Tunable data consistency
● Flexible schema design
● Data compaction
● CQL language (like SQL)
● Support for key languages and platforms
● No need for special hardware or
software

5. Architecture Overview
In Cassandra, all nodes play an identical role; there is no concept of a master node.
Cassandra’s built-for-scale architecture means that it is capable of handling large
amounts of data and thousands of concurrent users.
Cassandra’s architecture also means that, unlike other master-slave or sharded systems,
it has no single point of failure and therefore is capable of offering true continuous
availability and uptime.

6. CQL
Astyanix / Hector API:
SliceQuery<string,string,string>query=...
query.set Key (“x”)
query.set Column Family (“y”)
CQL:
SELECT A FROM Y WHERE ID=”X”

7. Cassandra Data Objects

8. Overview
Cassandra data model
COL1 VAL1 (TS1)
COL2 VAL2 (TS2)KEY

9. Writing Data

10. Reading Data

11. Rake
● Bad implemented range scan, Cassandra can not currently transfer
data;
● Compaction backing a request;
● Many settings made on the cluster level, type, storage strategy and
etc.;
● Counters.

12. Thank you for your attention!
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