B-trees and database indexes
B-trees and B+ trees are essential for efficient data lookups in database management systems like MySQL, Postgres, and MongoDB. They are structured to store key/value pairs in a way that optimizes search operations. MySQL's InnoDB engine relies heavily on B+ trees, where the choice of primary key significantly impacts performance. B-trees are well-suited for large data volumes that need persistent disk storage, and B+ trees offer advantages like storing all values at the leaf level and having linked lists for faster sequential access. Sequential keys generally improve performance over random or UUID keys.