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From Rainer Jung <rainer.j...@kippdata.de>
Subject Re: what is mod_jk parameter "connection_pool_timeout" in mod_proxy / mod_proxy_ajp / apache httpd?
Date Mon, 27 Apr 2009 16:00:37 GMT
On 27.04.2009 17:39, Arne Riecken wrote:
> Thanks, I did that bevore posting but did not understand id clearly. There
> is written:
> 
> "Any connections above smax are subject to a time to live or ttl. Apache
> will never create more than the Hard Maximum or max connections to the
> backend server."
> 
> "smax [...] Upto the Soft Maximum number of connections will be created on
> demand."
> 
> "max [...] In the Prefork MPM, this is always 1"
> 
> Because I use mpm-prefork as mentioned, default smax=max=1. Does it make
> sense to set smax to 0 to get a ttl for the one and only connection?

I would say "yes, it does make sense."

> So
> "zero connections will be created on demand"? Is it bad not to have a ttl
> for the one and only connection? When will that connection be closed without
> ttl? When Tomcat connectionTimeout triggers?

Yes, but then you rely on httpd to correctly detect the closed
connection. Usually you do that via activating cping/cpong. I would use
a ttl value as a kind of double safety net.

Whether closing idle connections or not is also related to

- what kind of connection pool is the backend using (relation to backend
threads, and how precious your thread resources are)

- are there other systems influencing idle connections between the web
server and the backend (like a firewall dropping idle connections)

Regards,

Rainer

> 2009/4/26 Rainer Jung <rainer.jung@kippdata.de>
> 
>> Look for "ttl" on page http://httpd.apache.org/docs/2.2/mod/mod_proxy.html

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