It’s double the size. 4 bytes * 2^31 (because Postgres doesn’t allow have unsigned ints, unlike MySQL) is 8.6 GB. That is quite a difference for an index, not to mention the table overhead.
You’re going to know well in advance before hitting this limit becomes an issue, and you’ll have plenty of time to either take a bit of downtime and do a column conversion, or do an online migration.
You’re going to know well in advance before hitting this limit becomes an issue, and you’ll have plenty of time to either take a bit of downtime and do a column conversion, or do an online migration.