diff --git a/doc/development/what_requires_downtime.md b/doc/development/what_requires_downtime.md index 8da6ad684f5..c4830322fa8 100644 --- a/doc/development/what_requires_downtime.md +++ b/doc/development/what_requires_downtime.md @@ -139,6 +139,8 @@ Adding or removing a NOT NULL clause (or another constraint) can typically be done without requiring downtime. However, this does require that any application changes are deployed _first_. Thus, changing the constraints of a column should happen in a post-deployment migration. +NOTE: Avoid using `change_column` as it produces inefficient query because it re-defines +the whole column type. For example, to add a NOT NULL constraint, prefer `change_column_null ` ## Changing Column Types