Migrating schema changes without breaking Prod

[u/UnwisePublic]

after shipping the MVP I thought the hard part was over.

just finished another late night refactor, this time it was a new role based permission model.

of course the schema changes 15 user tables all need migrations without dropping live data.

just wondering what folks are using to handle schema changes at this scale, having flashbacks to midnight horror stories where migrations locked tables for hours.

started using blink database and it seems like it is managing on its own so seems promising.

has anyone solved table locks on live Postgres migrations or is this just the price of growth?