Re: keepalives on MacOS X

On Tue, Jun 29, 2010 at 10:53 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> On Tue, Jun 29, 2010 at 11:28 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> On Tue, Jun 29, 2010 at 12:42 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> Yeah, a bit of rooting around in the Darwin sources shows that this
>>> value is used as a per-connection override for tcp_keepidle.  So it
>>> is a synonym.  Not sure if it's worth supporting when the other value
>>> can't be set too.  Maybe it'd be more useful to document that people can
>>> set the system-wide values if they're desperate.
>>
>> Well, the default value for tcp_keepidle is 2 hours, and the default
>> value for tcp_keepintvl is 75 seconds.  Assuming that tcp_keepcount
>> defaults to something reasonable (I think the default on Linux is 9),
>> the lion's share of the time will be waiting for tcp_keepidle - so
>> just the ability to reduce that value to something reasonable should
>> help a lot.  It's also not much code - proposed patch attached.
>
> src/interfaces/libpq/fe-connect.c
> +               appendPQExpBuffer(&conn->errorMessage,
> +                                                 libpq_gettext("setsockopt(TCP_KEEPIDLE) failed: %s\n"),
> +                                                 SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
>
> s/TCP_KEEPIDLE/TCP_KEEPALIVE

Fixed.

> Don't we need to change pq_getkeepalivesidle?

I changed this, but it doesn't seem to have done much. When I do
"show tcp_keepalives_idle" on MacOS X, I still get 0. gdb says
getsockopt is getting called, though. Am I doing something boneheaded
here, or is this just the behavior?

> In pq_setkeepalivesidle, if neither TCP_KEEPIDLE nor TCP_KEEPALIVE are
> supported, the following message is output.
>
>    setsockopt(TCP_KEEPIDLE) not supported

Fixed.

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