Storage Formats

Account number	Last name	First name	Purchase (in dollars)
1001	Green	Rachel	20.12
1002	Geller	Ross	12.25
1003	Bing	Chandler	45.25

Row Oriented Storage

In a row-oriented DBMS, the data would be stored as

1001,Green,Rachel,20.12;1002,Geller,Ross,12.25;1003,Bing,Chandler,45.25

Best suited for OLTP - Transaction data.

Columnar Oriented Storage

1001,1002,1003;Green,Geller,Bing;Rachel,Ross,Chandler;20.12,12.25,45.25

Best suited for OLAP - Analytical data.

1. Compression: Since the data in a column tends to be of the same type (e.g., all integers, all strings), and often similar values, it can be compressed much more effectively than row-based data.

2. Query Performance: Queries that only access a subset of columns can read just the data they need, reducing disk I/O and significantly speeding up query execution.

3. Analytic Processing: Columnar storage is well-suited for analytical queries and data warehousing, which often involve complex calculations over large amounts of data. Since these queries often only affect a subset of the columns in a table, columnar storage can lead to significant performance improvements.

https://mariadb.com/resources/blog/why-is-columnstore-important/