Re: use of SPI by postgresImportForeignStatistics

On Tue, Jun 16, 2026 at 10:34 AM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

> On Tue, Jun 16, 2026 at 8:04 AM Etsuro Fujita <etsuro(dot)fujita(at)gmail(dot)com>
> wrote:
> > I thought it would be a good idea to use
> > pg_restore_attribute_stats/pg_restore_relation_stats, because future
> > changes in attribute/relation stats would be absorbed by these
> > functions, which would lower the maintenance cost of this feature.
>
> I agree that we want to reuse code, but this isn't the right way to do
> it. For example, when we want to look up the OID of a relation from
> SQL, we can say 'whatever'::regclass::oid. But when we want to do the
> same thing from C, we don't construct a SELECT statement and execute
> it via SPI. Instead, we have functions like RangeVarGetRelidExtended()
> which provide access to the same underlying functionality more
> directly.
>
> Another example is converting strings to integers. The user calls
> int4in(), which then hands off the call to pg_strtoint32_safe(), which
> can also be called via pg_strtoint32(). Hence, C code should prefer to
> use pg_strtoint32(), while SQL will go through int4in(). Both
> ultimately reach the underlying pg_strtoint32_safe() function, but the
> interfaces are different, so that we can have it be suitable both for
> SQL access and for C access.
>
> This needs to work more like that. The underlying code that ingests
> and updates the stats should be shared, but the stuff that is specific
> to a FunctionCallInfo interface needs to be separated out so that we
> don't need to go through that when calling from C.
>
>
Back when pg_restore_attribute_stats and pg_restore_relation_stats were
being converted from positional to variadic functions, there was a patchset
or two (possibly un-posted, because I couldn't find it just now) where the
variadic functions re-marshalled the arguments into a call to a
fixed-parameter function. If that model were revived, we could have a more
conventional DirectFunctonCall() interface.

Is it possible that we never built a direct function call interface to a
variadic because we never needed one? Perhaps that time is now.