[asterisk-bugs] [Asterisk 0012127]: Using state_interface and Local channels allows several simultenous calls to be sent to agent

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A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=12127 
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Reported By:                atis
Assigned To:                putnopvut
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Project:                    Asterisk
Issue ID:                   12127
Category:                   Applications/app_queue
Reproducibility:            sometimes
Severity:                   minor
Priority:                   normal
Status:                     assigned
Asterisk Version:           SVN 
SVN Branch (only for SVN checkouts, not tarball releases):  trunk 
SVN Revision (number only!): 103809 
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             03-03-2008 12:26 CST
Last Modified:              03-11-2008 07:01 CDT
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Summary:                    Using state_interface and Local channels allows
several simultenous calls to be sent to agent
Description: 
I've seen this situation on 8-CPU 3GHz Xeon, that agent gets 4 queue calls
simultaneously. 

For now i've been able to avoid this by checking/setting group at
beginning of Local channel, setting call-limit=1 for SIP peers (only for
those who shouldn't receive more than 1 call simultaneously) and checking
group upon unsuccessful Dial from Local channel. Those 3 fixes together are
giving some good results for one most-problematic queue, however that's not
a permanent and stable solution. If queue is creating several channels at
the same time, on slower but multi-cored systems this could lead to race
condition between GROUP_COUNT and Set(GROUP()) in two parallel channels,
and call-limit=1 also can't always be set.

I'm not sure if this can be implemented in good way, but I think the most
appropriate solution for this would be that Queue is setting device state
of Local channel, and other queue(s) (if member is in multiple queues)
receives event from first queue's devicestate change.

My system is Asterisk 1.4.14 with backported state_interface from r103809
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---------------------------------------------------------------------- 
 atis - 03-11-08 07:01  
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Removing call from update_dial_status to update_status works perfectly
together with state_interface. We have run numerous tests, and there's no
(Unknown) state anymore. As queue dials agents in (Unknown) state, this
helps increasing performance, because no channels are created.

However there's a window between creation of Local channel and dialing to
actual SIP device. I see that in trunk there's devstate support for local
channels, however backporting that doesn't help (as queue doesn't check
state of local channel anymore). So, with having second interface for
queue_member, it's status should be calculated from both - interface and
state_interface. This somehow is contradictory to purpose of
state_interface, so maybe some option could be added for this purpose? 

Issue History 
Date Modified   Username       Field                    Change               
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03-11-08 07:01  atis           Note Added: 0083709                          
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