Re: keepalives_* parameters usefullness

Simon Riggs  writes:

> On Mon, Jul 4, 2011 at 9:42 AM, Jaime Casanova  wrote:
>
>> i even used getsockopt() to ensure TCP_KEEPIDLE was being setted and
>> tried to set it myself with setsockopt() with the same results.
>
> There's a list of preconditions as to when these settings take effect,
> otherwise they are a no-op.
>

do we know what those preconditions are? TFM just says:
"""
keepalives_idle
Controls the number of seconds of inactivity after which TCP should send
a keepalive message to the server. A value of zero uses the system
default. This parameter is ignored for connections made via a
Unix-domain socket, or if keepalives are disabled. It is only supported
on systems where the TCP_KEEPIDLE or TCP_KEEPALIVE socket option is
available, and on Windows; on other systems, it has no effect.
"""

which made me think that on my debian system it should work so maybe we
want to document those preconditions, even a statement indicating that
other factors can prevent this working as expected would be good

-- 
Jaime Casanova         www.2ndQuadrant.com
Professional PostgreSQL 
Soporte 24x7, desarrollo, capacitación y servicios