Columnar storage in MariaDB is a database storage engine designed to use as little disk I/O as possible while querying large amounts of data. It stores data in columns rather than in rows which is more efficient for many types of queries. Also, it compresses data for storage which helps in saving disk space. This type of storage is particularly useful for analytical workloads and big data processing where only a specific column of data is required in a big table rather than all the rows.
