Greatly depends on the database in question. For MySQL I heavily recommend using pt-online-schema-change[1] from Percona Toolkit[2]. In all cases though you s

Greatly depends on the database in question. For MySQL I heavily recommend using pt-online-schema-change[1] from Percona Toolkit[2]. In all cases though you should have a change management process where the schema change is documented, reviewed, and approved and only a small number of people have the necessary access to run these types of changes in production. Change management is your friend. 1: https://www.percona.com/doc/percona-toolkit/3.0/pt-online-schema-change.html https://www.percona.com/doc/percona-toolkit/3.0/pt-online-sc... 2: https://www.percona.com/software/database-tools/percona-toolkit https://www.percona.com/software/database-tools/percona-tool...