Group By, Count, Sum, Min, Max, and Average Fields in ORC Data Online

Apache ORC

Apache ORC (Optimized Row Columnar) is a self-describing, columnar file format that supports high compression ratios and fast data retrieval. ORC supports complex types, including structs, lists, maps, and unions. ORC files are divided into blocks of data (stripes) containing statistics (such as min, max, sum, and count) and lightweight indexing which can be used to skip over irrelevant data during queries. ORC also supports predicate pushdown, meaning that filters can be applied as the data is read from disk, reducing the amount of data loaded into memory and processed. Due to its high performance in terms of compression and speed of access, ORC is particularly well-suited for heavy read operations and is commonly used in data warehousing and analytics applications.