Re: Use pgstat_kind_infos to read fixed shared stats structs

On Tue May 7, 2024 at 1:29 PM CDT, Andres Freund wrote:
> Hi,
>
> On 2024-05-06 14:07:53 -0500, Tristan Partin wrote:
> > Instead of needing to be explicit, we can just iterate the
> > pgstat_kind_infos array to find the memory locations to read into.
>
> > This was originally thought of by Andres in
> > 5891c7a8ed8f2d3d577e7eea34dacff12d7b6bbd.
> >
> > Not a fix, per se, but it does remove a comment. Perhaps the discussion will
> > just lead to someone deleting the comment, and keeping the code as is.
> > Either way, a win :).
>
> I think it's a good idea. I'd really like to allow extensions to register new
> types of stats eventually. Stuff like pg_stat_statements having its own,
> fairly ... mediocre, stats storage shouldn't be necessary.

Could be useful for Neon in the future too.

> Do we need to increase the stats version, I didn't check if the order we
> currently store things in and the numerical order of the stats IDs are the
> same.

I checked the orders, and they looked the same.

1. Archiver
2. BgWriter
3. Checkpointer
4. IO
5. SLRU
6. WAL

--
Tristan Partin
Neon (https://neon.tech)