>
> > 2019-04-11 19:39:44.450844500 tuples: 19150 removed, 2725811 remain,
> 465 are dead but not yet removable
>
> What Jeff said. This vacuum spent a lot of time, only to remove miserly
> 19k tuples, but 2.7M dead tuples remained ... probably because you have
> long-running transactions preventing vacuum from removing them. Maybe
> that was pg_dump.
>
Wouldn't "dead but not yet removable" be high if there were long running
transactions holding onto old row versions?