Correlation between NETTYPE and VPCLASS

Hello, Is there any correlation between the values of the following two parameters VPCLASS NETTYPE I mean if the value of numcpus is 6 in VPCLASS i.e VPCLASS cpu,num=6,aff=17-22,noage, then is it necessary that the value of NETTYPE should be somewhat like the following NETTYPE ipcshm,6,250,CPU NETTYPE tlitcp,6,250,NET In this case 6 is common in both VPCLASS and NETTYPE parameters Regards, Kamran

Hamran The 6 in NETTYPE define the number of poll threads you want to bring up. Generally, one poll thread need to run on one VP. Hence the num=6 in VPCLASS. Please refer the details to below text or informix information center. Regards. -Ping ======================================================================== Manage network parameters for optimal communication performance The DBSERVERNAME and DBSERVERALIASES parameters correspond to entries in the first column of the sqlhosts file. A NETTYPE entry may specify an interface/protocol combination. The NETTYPE is not paired with the DBSERVER or DBSERVERALIAS entry, but the actual line in the sqlhosts file that has that corresponding protocol in the second column. The database server will run one or more poll threads for each unique NETTYPE entry, as defined by how many poll threads are allocated. The NETTYPE configuration parameter also provides additional configuration information for a corresponding interface/protocol combination. This allows a DBA to allocate an initial buffer to handle users as well as allocating more than one poll thread for an interface/protocol combination. NETTYPE also will designate the virtual-processor class (CPU or NET) on which the poll threads will do their work. Poll threads can run either on CPU virtual processors (VPs) or on network VPs. Poll threads generally run more efficiently on CPU VPs for single-CPU machines. On a multiprocessor computer with a large number of remote clients, however, running them on a NET VP may get better throughput. By default, if NETTYPE is not set for an interface/protocol combination, the database server will run poll threads inline. By default, poll threads for the specific interface/protocol combination that match the DBSERVERALIAS will run on the CPU VP, as the DB server assumes that this is the primary interface with any users. For other interface/protocol combinations, if no VP class is specified, the default is to run those poll threads on a NET VP. If a poll thread is running on NET VPs, then the engine will start up a NET VP for each poll thread. This is because each poll thread requires its own virtual processor. This is true also for poll threads running inline (in other words, on the CPU VPs). If you specify CPU for the VP class, only one poll thread can run on each CPU VP. if the database server does not have enough CPU VPs, the database server will fork NET VPs to handle the overflow. One poll thread and, consequently, one virtual processor per network interface/protocol combination is usually sufficient for smaller systems. For systems that can have 200 or more concurrent network users, better performance might result from adding more poll threads (with the concomitant network virtual processors). With high user load, you may need to experiment to determine the optimal configuration of poll threads (whether inline or running on NET VPs) and number of network VPs to start (if running on network virtual processors). In the situation in which the database server is not handling connection requests satisfactorily for a given interface/protocol combination of a single port and the corresponding listener thread, you can improve connection throughput in the following ways: * Allocating additional listener threads * Adding another network-interface card --- On Wed, 5/6/09, KAMRAN HAQ <khaq@i2cinc.com> wrote: > From: KAMRAN HAQ <khaq@i2cinc.com> > Subject: Correlation between NETTYPE and VPCLASS [15687] > To: ids@iiug.org > Date: Wednesday, May 6, 2009, 6:20 AM > Hello, > Is there any correlation between the values of the > following two parameters > > VPCLASS > NETTYPE> > I mean if the value of numcpus is 6 in VPCLASS i.e > > VPCLASS cpu,num=6,aff=17-22,noage, > > then is it necessary that the value of NETTYPE should be > somewhat like the > following > > NETTYPE ipcshm,6,250,CPU > NETTYPE tlitcp,6,250,NET> > In this case 6 is common in both VPCLASS and NETTYPE > parameters > > Regards, > Kamran > > > ******************************************************************************* > > Forum Note: Use "Reply" to post a response in the > discussion forum. > >

Good question! As far as TCP ans stream pipe connection types, which should always be configured in NET VPs, the number of CPU VPs is irrelevant as the NET VPs are separate processes. You just need to configure enough of them so that they are each managing fewer than 350 connections for best performance. For SHM connections, you will be configuring those in CPU VPs. If the SHM connection is there ONLY for maintenance and the occassional local user, then you can live with only one SHM poll thread set in NETTYPE, though I recommend at least two if you have two or more CPU VPs just in case the primary CPU VP is hung. However, if the SHM connections will be used by many users constantly, then there must be a poll thread running in every CPU VP to aid the engine in load balancing across the VPs and to optimize server response time during peak periods. I've explained my reasoning on this subject many times. You can search the IDS forum and CDI archives for those posts or look in the Informix FAQ. Art Art S. Kagel Oninit (www.oninit.com) IIUG Board of Directors (art@iiug.org) Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Oninit, the IIUG, nor any other organization with which I am associated either explicitly or implicitly. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Wed, May 6, 2009 at 7:20 AM, KAMRAN HAQ <khaq@i2cinc.com> wrote: > Hello, > Is there any correlation between the values of the following two parameters > > VPCLASS > NETTYPE> > I mean if the value of numcpus is 6 in VPCLASS i.e > > VPCLASS cpu,num=6,aff=17-22,noage, > > then is it necessary that the value of NETTYPE should be somewhat like the > following > > NETTYPE ipcshm,6,250,CPU > NETTYPE tlitcp,6,250,NET> > In this case 6 is common in both VPCLASS and NETTYPE parameters > > Regards, > Kamran > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --001636c5a537a7593804693f2e46