Chris Angelico wrote:
> On Thu, Dec 6, 2012 at 5:56 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I suspect this action isn't dropping the TCP connection. It's only
>> equivalent to a momentary glitch in your network connectivity --- and
>> you'd be very unhappy if that caused TCP connections to go down, because
>> networks have glitches all the time. Generally, the operating system
>> tries hard to prevent applications from even knowing that a glitch
>> happened. (Connections will time out eventually if connectivity doesn't
>> come back, but typically such timeouts are many minutes. Possibly
>> whatever your real complaint is could be addressed by twiddling the TCP
>> timeout parameters for the socket.)
>
> Yep. For a better test, try taking the interface down for a good while
> (several minutes), or actually shut down the Postgres server at the
> other end.
I find PostgreSQL connections, particularly with listen/notify set up,
to be fairly sensitive to disconnection. This is particularly the case
with apps written using either Delphi or Lazarus, where a session is
kept live for an extended period rather than simply being used to
transfer a query and resultset.
This isn't a recent thing, and I'm definitely not saying that it's a
Postgres issue. I've tried forcing random connection drops at the
application level in the past and have never been able to characterise
the problem.
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
