[cisco-voip] CM database query

[Ryan Ratliff]

Nothing database related happens at all during a call.  Each server keeps the status of all DNs, devices, etc in memory.  For devices registered to another node then the other servers know simply what node has ownership of that line/device.  The database is used only for replication in 6.x and later and replication is what generates change notifications.  

Database lookups are slow and expensive (in processing time).  The fewer of them we have to do the faster the system can run.

The only time I can think of off the top of my head that CUCM will do a real-time database lookup is if a device is registering that we don't have in memory (fyi ccm will load into memory details for every device in a cucm group where that node is primary or secondary for registration to make failover happen faster, tertiary nodes do not load devices into memory at startup).  This is why transient device connections from devices that aren't configured in the db cause so many performance problems.  Each time that device tries to register ccm looks in memory, doesn't see it, then it goes to the in-memory db (7.x and later) and doesn't see it, then it goes to check the physical disk database.  As soon as you have to look up anything on the disk you are taking a performance hit.

-Ryan

On Aug 10, 2010, at 4:41 PM, Kevin Damisch wrote:

Nothing really.  Just doing verification of what actually occurs between the phone/pub/sub during a simple call in regards to the database queries for pattern lookups such as a DN, route pattern, etc.  So, if a phone is registered to a subscriber, and dials a route pattern for example, does the database query for that pattern occur on the publisher or the subscriber?
 
From: Dennis Heim [mailto:Dennis.Heim at cdw.com] 
Sent: Tuesday, August 10, 2010 3:34 PM
To: Kevin Damisch; cisco-voip at puck.nether.net
Subject: RE: CM database query
 
What are you trying to accomplish?
 
Dennis Heim
Network Voice Engineer
CDW  Advanced Technology Services
11711 N. Meridian Street, Suite 225
Carmel, IN  46032

317.569.4255 Office
317.569.4201 Fax
317.694.6070 Cell
dennis.heim at cdw.com
cdw.com/content/solutions/unified-communications/
 
 
From: cisco-voip-bounces at puck.nether.net [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Kevin Damisch
Sent: Tuesday, August 10, 2010 12:55 PM
To: cisco-voip at puck.nether.net
Subject: [cisco-voip] CM database query
 
In CM 6/7/8, if the phones are registered to the subscriber and the phone dials a DN, what query is done to the publisher database at that time?  Or, is all call processing and database queries done only on the subscriber?  This is assuming that the publisher is online.  Obviously, if the publisher is down, everything will be queried against the subscriber.
 
Thanks,
Kevin
 

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