Re: We should stop telling users to "vacuum that database in single-user mode"

On 2021-Mar-02, David Rowley wrote:

> However, I wonder if it's worth going a few steps further to try and
> reduce the chances of that message being seen in the first place.
> Maybe it's worth considering ditching any (auto)vacuum cost limits for
> any table which is within X transaction from wrapping around.
> Likewise for "VACUUM;" when the database's datfrozenxid is getting
> dangerously high.

Yeah, I like this kind of approach, and I think one change we can do
that can have a very large effect is to disable index cleanup when in
emergency situations. That way, the XID limit is advanced as much as
possible with as little effort as possible; once the system is back in
normal conditions, indexes can be cleaned up at a leisurely pace.

--
Álvaro Herrera Valdivia, Chile
"El destino baraja y nosotros jugamos" (A. Schopenhauer)