"read only" here means no in-place updates. See: * http://www.bzero.se/ldapd/btree.html -- we can build a new btree without destructively modifying any of the existing nodes * https://en.wikipedia.org/wiki/Lightning_Memory-Mapped_Database (a kv store built on similar ideas) * https://github.com/LMDB/sqlightning -- port of sqlite to use lmdb * https://emilypost.com/advice/everyday-etiquette -- in case English is not your 1st language, as your above comment might come off as rude