[tgv]

But is there a functional difference between push and pull in this case? Is there something that cannot be explained in terms of propagation? Perhaps timing: there's no reason for propagation to wait an hour or a day.

BTW, only last week I explained a potential problem of a DNS change with caching, and it was understood. There doesn't seem to be a need to simplify it.

[jon-wood]

There is absolutely a reason for propagation to wait an hour or a day, and you've set that value in the TTL field for the record in question. It stands for Time To Live and specifies how long downstream resolvers should cache the last value they saw before querying the authoritative server again, if you set that value to a few seconds then almost every DNS resolver in the world will get updated values within a few seconds as they expire the cached value.

[tgv]

The discussion was about caching vs propagation. You're already mixing them.