Connections & Host File

Database
Teradata Employee

Connections & Host File

Hello All,

I have seen the question concerning Virtual Circuits across multiple posts. One question which many Customer asks is "I have 10 PEs & theoretically, I should have 120*10 = 1200 Sessions in VP before getting the Virtual Circuit Error. Why am I getting Virtual Circuit Error when VP shows # of Sessions (Active+Idle+Block+Delay+Others) as much less than 1200 Sessions, say 700 Sessions". 

We always suggest Creating Abort Alert for Long Idle Sessions or configuring the Hosts file properly to ensure all the incoming connections aren't going to the PDN Node. For the 1st suggestion, it is easily setup by the DBAs. Concerning the 2nd suggestion, allow me to explain: Say, a Teradata System (TDP01) has 05 Nodes & each Node has 5 PEs. If the Hosts file is not using any COP entries & specify only TDP01, then all the connections from all Gateways are forwarded to the PDN Node only. In this case, the 05 PEs of PDN Node should theoretically accomodate 120*5 = 600 Sessions. As such, TDP01 should see Virtual Circuit Error when the # of Sessions in VP is approx 600. 

If the COP Entries are specified, then the incoming connections are sent to all the 05 Nodes of TDP01 in a round-robin manner. If so, coming back to Customer question: "I should have 120 * 05 Nodes * 05 PEs = 3000 Sessions in VP before getting the Virtual Circuit Error. Why am I getting Virtual Circuit Error when VP shows # of Sessions (Active+Idle+Block+Delay+Others) as much less than 3000 Sessions". 

I covered 01 Understanding  (02nd Paragraph) & 01 Question (03rd Paragraph). Anyone with the answer, kindly provide response whether my Understanding @ 02nd Para is correct & the answer to my Question @ 03rd Para.

Thanks In Advance,

Smarak