How does Hive improve performance with tables in ORC format?

Using the ORC format leads to a reduction in the size of the data stored, as this   file format has high compression ratios. As the data size is reduced, the time to read and write the data is also reduced. The ORC format improves query performance also by the way it stores data in a file. Data is stored in a columnar format and columns that are not needed in a query can be skipped, thus leading to better performance.