ICANN RDAP tech folks,

I wanted to comment on an aspect of the ICANN operational profile. 1.4.12, 1.4.13 and 1.5.14 indicate that domains, nameservers and entities should include an event with type "last update of RDAP database". It sounds like you are assuming that the database will have a timestamp as of which all data are consistent, like a snapshot. Modern distributed databases don't necessarily have such a timestamp. If the database is "eventually consistent" (see https://en.wikipedia.org/wiki/Eventual_consistency), updates to a particular object may not show up in database reads until some time later. Technically, the only guarantee is that the new, updated value will show up eventually.

So when we return a "last update time", that doesn't mean that the data being returned in the RDAP response is as fresh as what was written on or before the last update time. The read may lag behind the update. I am going to go ahead and set the last update time to the current time, because that's when the most recent update could have occurred. But that will not mean that the returned data is current as of that time, because such a guarantee is impossible in an eventually consistent database.

Thanks.

Brian