What are columnar databases used for and what advantages do they offer?

A columnar database stores data not by rows but by columns. This means all values of a single column are stored consecutively, not the entire row.

Advantages of columnar databases:

• Fast data access for analytics. When queries involve only a few columns, columnar databases read only the needed data, significantly speeding up processing.
• Efficient data compression. Values in a column are often similar in type and range, allowing better compression and space savings.
• Optimization of aggregations and calculations. Many analytical operations (sums, averages, counts) are faster because data of a single column is stored sequentially.

Example of use: business intelligence systems, data warehouses where high read speed and large data processing are critical.

Unlike traditional relational databases optimized for transactions (OLTP), columnar databases are better suited for analytical tasks (OLAP).