Re: please update ps display for recovery checkpoint

On Thu, Dec 03, 2020 at 09:18:07PM +0000, Bossart, Nathan wrote:
> I considered also checking that update_process_title was enabled, but
> I figured that these ps display updates should happen sparsely enough
> that it wouldn't make much of an impact.

Since bf68b79e5, update_ps_display is responsible for checking
update_process_title.  Its other, remaining uses are apparently just acting as
minor optimizations to guard against useless snprintf's.

See also https://www.postgresql.org/message-id/flat/1288021.1600178478%40sss.pgh.pa.us
in which (I just saw) Tom wrote:

> Seems like a good argument, but you'd have to be careful about the
> final state when you stop overriding update_process_title --- it can't
> be left looking like it's still-in-progress on some random WAL file.

I think that's a live problem, not just a concern for that patch.
It was exactly my complaint leading to this thread:

> But runs a checkpoint, which can take a long time, while the "ps" display still
> says "recovering NNNNNNNN".

-- 
Justin