Re: TCP keepalive support for libpq

On Tue, Jun 22, 2010 at 12:32 PM, Magnus Hagander <magnus@hagander.net> wrote:
>> Which brings us to the question of portability.  A quick search around
>> the Internet suggests that this is supported on recent versions of
>> Linux, Free/OpenBSD, AIX, and HP/UX, and it appears to work on my Mac
>> also.  I'm not clear how long it's been implemented on each of these
>> platforms, though.  With respect to Windows, it looks like there are
>> registry settings for all of these parameters, but I'm unclear whether
>> they can be set on a per-connection basis and what's required to make
>> this happen.
>
> I looked around quickly earlier when we chatted about this, and I
> think I found an API call to change them for a socket as well - but a
> Windows specific one, not the ones you'd find on Unix...

That, in itself, doesn't bother me, especially if you're willing to
write and test a patch that uses them.

What does bother me is the fact that we are engineering a critical
aspect of our system reliability around vendor-specific implementation
details of the TCP stack, and that if any version of any operating
system that we support (or ever wish to support in the future) fails
to have a reliable implementation of this feature AND configurable
knobs that we can tune to suit our needs, then we're screwed.  Does
anyone want to argue that this is NOT a house of cards?

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