Almost whenever I run an alter table in MySQL, I think back to a conversation with Marco Arment at SXSW 15 years ago, about how Tumblr’s database was so big it was faster to add new tables instead of changing existing columns or indexes. MySQL has improved a lot since then.

@manton if it’s still disrupting your operations too much you can look into pt-online-schema-change or gh-ost, there’s a nice comparison here https://severalnines.com/blog/online-schema-change-mysql-mariadb-comparing-github-s-gh-ost-vs-pt-online-schema-change/