On Tue, Mar 14, 2023 at 02:02:19PM +0900, Kyotaro Horiguchi wrote:
> Regarding huge_page_active, its value remains constant throughout a
> postmaster's lifespan. In this regard, GUC may be a better fit for
> this information. The issue with using GUC for this value is that the
> postgres command cannot report the final value via the -C option,
> which may be the reason for the third alternative "unknown".
>
> I slightly prefer using a function for this, as if GUC is used, it can
> only return "unknown" for the command "postgres -C
> huge_page_active". However, apart from this advantage, I prefer using
> a GUC for this information.
The main advantage of a read-only GUC over a function is that users
would not need to start a postmaster to know if huge pages would be
active or not. This is the main reason why a GUC would be a better
fit, in my opinion, because it makes for a cheaper check, while still
allowing a SQL query to check the value of the GUC.
--
Michael
