Tom Lane wrote:
Oliver Jowett <[EMAIL PROTECTED]> writes:

Here's a patch that adds four new GUCs:

 tcp_keepalives (defaults to on, controls SO_KEEPALIVE)
 tcp_keepalives_idle (controls TCP_KEEPIDLE)
 tcp_keepalives_interval (controls TCP_KEEPINTVL)
 tcp_keepalives_count (controls TCP_KEEPCNT)

Do you think the system defaults are really going to be port-specific?

I don't understand what you mean. TCP_* override the system defaults on a per-connection basis, if that's what you mean.

I'm slightly annoyed by the number of syscalls this adds to every
connection startup ... getting rid of redundant getsockopt calls would
help.  Getting rid of redundant setsockopt calls (ie, a call to
establish the value that we already know is in force) would help more.

I originally did this but went in favor of simpler code. Are the extra syscalls an issue? I didn't think they were that expensive..

Alternatively, we could lose the frammish that PostgreSQL can tell you
what the system defaults are: 0 in the GUC just means "do nothing",
not "find out what the current setting is on the off chance that the
user might want to know".

I didn't do this as it meant that using SET tcp_whatever = 0 does *not* reset the setting to what you'd get with a value of 0 in postgresql.conf, which seemed confusing to me.

This could all get simpler if we didn't allow per-connection changing of that GUC (i.e. set it once at startup and forget about it), which probably isn't unreasonable. I wonder if those socket options get inherited from the listening socket? Will check.


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