Re: TCP keepalive support for libpq

On Tue, Feb 09, 2010 at 09:34:10AM -0500, Andrew Chernow wrote:
> Tollef Fog Heen wrote:
> >(please Cc me on replies, I am not subscribed)
> >
> >Hi,
> >
> >libpq currently does not use TCP keepalives. This is a problem in our
> >case where we have some clients waiting for notifies and then the
> >connection is dropped on the server side. The client never gets the FIN
> >and thinks the connection is up. The attached patch unconditionally
> >adds keepalives. I chose unconditionally as this is what the server
> >does. We didn't need the ability to tune the timeouts, but that could
> >be added with reasonable ease.
>
> ISTM that the default behavior should be keep alives disabled, as it is
> now, and those wanting it can just set it in their apps:
>
> setsockopt(PQsocket(conn), SOL_SOCKET, SO_KEEPALIVE, ...)

I disagree. I have clients who have problems with leftover client connections
due to server host failures. They do not write apps in C. For a non-default
change to be effective we would need to have all the client drivers, eg JDBC,
psycopg, DBD-DBI, and the apps like psql make changes to turn it on. Adding
this option as a non-default will not really help.

-dg

--
David Gould daveg(at)sonic(dot)net 510 536 1443 510 282 0869
If simplicity worked, the world would be overrun with insects.