Re: beta3 & the open items list

From: Florian Pflug <fgp(at)phlo(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Greg Stark <gsstark(at)mit(dot)edu>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: beta3 & the open items list
Date: 2010-06-20 10:46:12
Message-ID: C63B6B84-16F9-4EA5-82E1-7C54EC38D31C@phlo.org
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On Jun 20, 2010, at 7:18 , Tom Lane wrote:
> Florian Pflug <fgp(at)phlo(dot)org> writes:
>> On Jun 19, 2010, at 21:13 , Tom Lane wrote:
>>> This is nonsense --- the slave's kernel *will* eventually notice that
>>> the TCP connection is dead, and tell walreceiver so. I don't doubt
>>> that the standard TCP timeout is longer than people want to wait for
>>> that, but claiming that it will never happen is simply wrong.
>
>> No, Robert is correct AFAIK. If you're *waiting* for data, TCP
>> generates no traffic (expect with keepalive enabled).
>
> Mph. I was thinking that keepalive was on by default with a very long
> interval, but I see this isn't so. However, if we enable keepalive,
> then it's irrelevant to the point anyway. Nobody's produced any
> evidence that keepalive is an unsuitable solution.

Yeah, I agree. Just enabling keepalive should suffice for 9.0.

BTW, the postmaster already enables keepalive on incoming connections in StreamConnection() - presumably to prevent crashed clients from occupying a backend process forever. So there's even a clear precedent for doing so, and proof that it doesn't cause any harm.

best regards,
Florian Pflug

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