Re: Posix Shared Mem patch

On Thu, Jun 28, 2012 at 7:05 AM, Magnus Hagander <magnus(at)hagander(dot)net> wrote:
> Do we really need a runtime check for that? Isn't a configure check
> enough? If they *do* deploy postgresql 9.3 on something that old,
> they're building from source anyway...
[...]
>
> Could we actually turn *that* into a configure test, or will that be
> too complex?

I don't see why we *couldn't* make either of those things into a
configure test, but it seems more complicated than a runtime test and
less accurate, so I guess I'd be in favor of doing them at runtime or
not at all.

Actually, the try-a-one-page-mapping-and-see-if-you-get-EINVAL test is
so simple that I really can't see any reason not to insert that
defense. The fork-and-check-whether-it-really-works test is probably
excess paranoia until we determine whether that's really a danger
anywhere.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company