Columnar storage is a data storage method that organizes data in columns rather than rows. This approach allows for efficient data retrieval, especially for analytical queries that often access specific columns rather than entire rows. By storing data in this way, systems can reduce the amount of data read from disk, leading to faster query performance. In columnar storage, each column is stored separately, which enables better compression techniques. This is particularly useful for large datasets, as similar data types within a column can be compressed more effectively. Popular databases that utilize columnar storage include Apache Cassandra and Google BigQuery.