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Re: productivity?

2011-08-23 15:10:00
On 2011-08-23 12:15:20 -0700, Murray S. Kucherawy wrote:
BTW, I've never observed a sendmail to keep open an idle connection for
that long. Maybe that limit doesn't apply to "normal" connections
(according to the document you cited it only applies to "IPC
connections"[1]) or maybe that limit is only reached under rare
circumstances. I just tested an out-of-the-box sendmail-8.13 (with
ConnectionCacheTimeout=5m) and it sends the QUIT immediately after the
250 response to DATA.

Sendmail's connection cache only applies during queue runs.  The
entire connection cache is capped at a certain number of connections,
which is where the LRU comes in; when it needs to make a connection to
a server that is not currently cached, the most idle one is closed
down and the new one is established.  When the queue run completes,
any cached connections remaining are also closed.

So really you would only ever see a cached connection stay open that
long if, for a connection cache of size N, it had to connect to some
small server, but the remaining (rather large) queue went only to a
specific N-1 other servers, and so the first one sat idle for that
long.  Seems rather like a corner case.

Right. Especially since N is usually very small (default is 1 according
to the 8.12 docs, 2 for 8.13 on a Redhat box), it seems rather unlikely
that a connection would sit idle for an extended time during a queue

Thanks for the explanation.


   _  | Peter J. Holzer    | Web 2.0 könnte man also auch übersetzen als
|_|_) | Sysadmin WSR       | "Netz der kleinen Geister".
| |   | hjp(_at_)hjp(_dot_)at         | 
__/   | |  -- Oliver Cromm in desd

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