Re: Add pg_stat_kind_info system view

Hi,

On Tue, Jun 30, 2026 at 03:42:40PM +0900, Michael Paquier wrote:
> On Wed, Jun 24, 2026 at 05:31:12AM +0000, Bertrand Drouvot wrote:
> > But header in pgstat_internal.h mentions:
> > 
> > "
> >  * Definitions for the PostgreSQL cumulative statistics system that should
> >  * only be needed by files implementing statistics support (rather than ones
> >  * reporting / querying stats).
> > 
> > "
> > 
> > So it looks like that we are breaking this convention here. Maybe add helper
> > function(s)?
> 
> Yeah.  Pulling pgstat_internal.h in pgstatfuncs.c is not great.  The
> code acts as a barrier as the internal part and the fields data
> retrieved by the functions.  A couple of alternatives I can think of:
> - Put this new function in a new file under activity, named blankly
> pgstat_kind.c.
> - Move the necessary stuff out of pgstat_internal.h into a new header,
> or just pgstat_kind.h with a !FRONTEND block.
> - Use a new wrapper function that copies the data we need into an
> intermediate structure.  This is just a new pgstat_get_kind_info().
> 
> Among these two, putting pg_stat_get_kind_info() into a new file feels
> much better than splitting the contents of pgstat_internal.h, which is
> kind of the central in-core shmem-side facility.

I do agree. That said, creating a new file only for one function looks a bit
weird (but I can not think of a better option though).

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
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