On 2018-12-10 15:38:55 -0500, Tom Lane wrote: > Also, I'm not entirely sure whether there's anything in our various > replication logic that's dependent on vacuum truncation taking AEL. > Offhand I'd expect the reduced use of AEL to be a plus, but maybe > I'm missing something.
It'd be a *MAJOR* plus. One of the biggest operational headaches for using a HS node for querying is that there'll often be conflicts due to vacuum truncating relations (which logs an AEL), even if hot_standby_feedback is used. There's been multiple proposals to allow disabling truncations just because of that.