title: Migrating `int` to `bigint` in PostgresSQL without any downtime?
body: <p>I have a database that is going to experience the <a href="https://m.signalvnoise.com/update-on-basecamp-3-being-stuck-in-read-only-as-of-nov-8-922am-cst/" rel="noreferrer">integer exhaustion problem</a> that Basecamp famously faced back in November. I have several months to figure out what to do.</p>
  
  <p>Is there a no-downtime-required, proactive solution to migrating this column type? If so what is it? If not, is it just a matter of eating the downtime and migrating the column when I can?</p>
  
  <p>Is <a href="https://tech.coffeemeetsbagel.com/schema-migration-from-int-to-bigint-on-a-massive-table-in-postgres-aabb835c3b84" rel="noreferrer">this article sufficient</a>, assuming I have several days/weeks to perform the migration <strong>now</strong> before I'm forced to do it when I run out of ids?</p>