Re: Keepalives win32

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Kevin Grittner" <Kevin.Grittner@wicourts.gov>
Cc: "Magnus Hagander" <magnus@hagander.net>, "Pavel Golub" <pavel@gf.microolap.com>, "Bruce Momjian" <bruce@momjian.us>, "PostgreSQL-development" <pgsql-hackers@postgresql.org>
Date: 2010-06-30T15:46:48Z
Lists: pgsql-hackers
"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> I also think we may want to suggest that for most environments,
> people may want to change these settings to something more
> aggressive, like a 30 to 120 second initial delay, with a 10 or 20
> second retry interval.  The RFC defaults seem approximately right
> for a TCP connection to a colony on the surface of the moon, where
> besides the round trip latency of 2.5 seconds they might have to pay
> by the byte.

Well, the RFCs were definitely written at a time when bandwidth was a
lot more expensive than it is today.

> In other words, it is *so* conservative that I have
> trouble seeing it ever causing a problem compared to not having
> keepalive enabled, but it will eventually clean things up.

Yes.  This is a large part of the reason why I think it's okay for us to
turn libpq keepalive on by default in 9.0 --- the default parameters for
it are so conservative as to be unlikely to cause trouble.  If Windows
isn't using RFC-equivalent default parameters, that seems like a good
reason to disregard the system settings and force use of the RFC values
as defaults.

			regards, tom lane