We'd love to but the problem is that the hot standby is still read-only, which prevents even a transaction BEGIN from being executed on it. As the Nuxeo framework is pluggable, we don't have any way of knowing for a given HTTP request if the whole work to be executed will be read-only w.r.t. the database, or if somewhere a listener will want to write data. So in all cases we have to start a transaction very early, which prevents a hot standby from being used.
A way to improve this would be to have at the URL level some way of discriminating between requests that are going to be purely read-only and those who don't, but that's not something we have today.
Postgres-XC may be a better bet, but we haven't tested it yet.
