> For the complete documentation index, see [llms.txt](https://functional.gitbook.io/database_comparison_report/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://functional.gitbook.io/database_comparison_report/cassandra.md).

# Cassandra

Cassandra is a decentralized system developed by Apache. Cassandra is a free Java-based DBMS whose strength is in its multi-replication and multi-deployment features. These peculiarities allow for numerous query copying and deploying all of them at the same time. Being rapidly scalable, Cassandra allows for managing large data volumes by replicating them into multiple nodes. It eliminates the problem of database crashes – if some of the nodes fail at any time, it’s replaced immediately, and the system keeps working as long as at least one single node is safe.

<figure><img src="/files/EcK9ffWRlki2cxAHdkz2" alt=""><figcaption></figcaption></figure>

Cassandra uses its own query language, CQL. In its syntax, it’s very similar to SQL but doesn’t apply joins, replacing them with so-called column families. And the second difference is that not all columns in a table are stored for subqueries. Some of them are used as clustering columns, where adjacent data is put next to each other for fast retrieval. Why does that matter? It provides faster querying from massive datasets, accelerating data processing.