jkmanager: how to interpret "Current number of backend connections"

[Martin Knoblauch <kn...@gmail.com>]

Hi,

 our environment is (I know, some are old ...):

Apache 2.2.21
mod_jk-1.2.40
Tomcat 7.0.42

My question is how to interpret the numbers from "jkmanager", expecially
the Busy/Max/Con numbers.


"Busy" and "Max" make sense to me. "Busy" is always less than "Max" and
"Max" gets bumped up from time to time. Matches the description.

Now, "Con" seems to grow steadily over time and is not reset when we do a
manual "Reset" of the worker status. Somehow this does not match the
description of "Current number of backend connections". At least not for me
:-)

Cheers
Martin
-- 
------------------------------------------------------
Martin Knoblauch
email: k n o b i AT knobisoft DOT de
www: http://www.knobisoft.de

Re: jkmanager: how to interpret "Current number of backend connections"

[Martin Knoblauch <kn...@gmail.com>]

On Mon, Jun 30, 2014 at 5:18 PM, Martin Knoblauch <kn...@gmail.com>
wrote:

> Hi,
>
>  our environment is (I know, some are old ...):
>
> Apache 2.2.21
> mod_jk-1.2.40
> Tomcat 7.0.42
>
> My question is how to interpret the numbers from "jkmanager", expecially
> the Busy/Max/Con numbers.
>
>
> "Busy" and "Max" make sense to me. "Busy" is always less than "Max" and
> "Max" gets bumped up from time to time. Matches the description.
>
> Now, "Con" seems to grow steadily over time and is not reset when we do a
> manual "Reset" of the worker status. Somehow this does not match the
> description of "Current number of backend connections". At least not for me
> :-)
>
> Cheers
> Martin
>
>
OK, seems the continuous growing  of the "Current number of backend
connections" numbers is related to having timeouts configured. It also
seems to have started between mod_jk-1.2.32 and mod_jk-1.2.37. I can see
some heavy redo of the handling of the "connected" counter.

In any case, the following configuration seems to trigger the behaviour:

worker.template.type=ajp13
worker.template.lbfactor=1
worker.template.prepost_timeout=15000
worker.template.connect_timeout=15000
worker.template.ping_timeout=15000
worker.template.ping_mode=A
worker.template.connection_ping_interval=180
worker.template.retries=3
worker.template.connection_pool_timeout=30

Without setting the timeout values, the displayed number of backend
connections seems to be stable. I suspect a missing decrement somewhere,
just hard to say where.

Cheers
Martin
-- 
------------------------------------------------------
Martin Knoblauch
email: k n o b i AT knobisoft DOT de
www: http://www.knobisoft.de