Re: shared-memory based stats collector

Hi,

On 2021-03-16 12:54:40 -0700, Andres Freund wrote:
> I did consider command_progress.c too - but that seems confusing because
> there's src/include/commands/progress.h, which is imo a different layer
> than what pgstat/backend_progress provide. So I thought splitting things
> up so that backend_progress.[ch] provide the place to store the progress
> values, and commands/progress.h defining the meaning of the values as
> used for in-core postgres commands would make sense.  I could see us
> using the general progress infrastructure for things that'd not fit
> super well into commands/* at some point...

Thinking about it some more, having the split between backend_status.h
and commands/progress.h actually makes a fair bit of sense from another
angle: Commands utilizing workers. backend_status.h provides
infrastructure to store progress counters for a single backend, but
multiple backends can participate in a command...

I added some comments to the header to that end.

Greetings,

Andres Freund