IDS Forum

Re: AW: NETTYPE

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Date:

Art,

Help me understand why we never want to put TCP poll threads on CPU VP's.
I might well agree that we'd not want to put any poll threads on CPU VP's,
since we want CPU VP's pretty much exclusively doing CPU VP kind of stuff,
rather than listening for connections. What I don't understand is why it
is any better to have a shared memory poll thread on the CPU VP than it is
to have a TCP poll thread.

My understanding of the connection process is that the VP listening for
whichever type of connection you're coming in on (TCP or shared memory)
picks up the request, it forces the creation of an sqlexec thread, and then
hands off the session to the sqlexec thread, then goes back to listening.
I understand from the documentation (and from some real life experiences
that others I know have had) that the CPU VP's make faster connections, but
given that the functionality of the poll threads is the same, even that
doesn't make much theoretical sense. Is it because the CPU VP's have fewer
yield points than the NET VP's? I'm not sure where/why you'd yield in the
connection process anyway, so that doesn't make much sense, but it's the
only thing I can think of.

In Edmund's case, given that the existing configuration has 4 tli poll
threads, my assumption is that most users are connecting via TCP, so I
don't know that I'd decrease the number of VP's handling those connections.
I'd probably go with something like this:

NETTYPE ipcshm 1,50,NET
NETTYPE tlitcp 1,200,CPU
NETTYPE tlitcp 3,200,NET

I'm guessing that the only shared memory connections made for this instance
are maintenance ones (and the additional shared memory listener is the
result of earlier misunderstandings -- I've done that in the past), so
you'd only need 1 poll thread, and it doesn't have to be lightning fast.
The 1 TCP poll thread that listens on the CPU VP would handle most of the
connections, and do so more quickly than a NET VP would, but in cases
where the instance was slammed, the NET TCP poll threads would pick up the
slack at a slightly slower rate. Alternatively, increase the tlitcp/NET VP
threads by 1, and get rid of the CPU VP poll threads altogether.

If I'm off base, please let me, and the rest of us know... I know that
there are TONS of misunderstandings about the poll threads and VP classes
out there...

Thanks.

Dan Michaelis
813.978.6534 (office)
813.303.3225 (pager)
dan.michaelis@verizon.com



"ART KAGEL, ...."
<KAGEL@bloomberg. To: ids@iiug.org
net> cc:
Sent by: Subject: Re: AW: NETTYPE [464]
forum.subscriber@
iiug.org


02/21/2003 08:18
AM







AHHHH! NEVER put TCP listeners in CPU VPs and NEVER put shared memory poll
threads in NET VPs. Either will burn CPU time, slow down response time,
and
cause the machine to do little else but poll for Informix connections &
requests. Also unless you have at least 6 CPU VPs, the configuration below
will
allocate any poll/listener threads that exceed the number of CPU VPs to
NET VPs
. However, since you have entered the TCP NETTYPE first, if you say have 4
CPU
VPs that would be the worst case as all 4 CPU VPs would be running TCP poll
threads and there would be 2 NET VPs running shared memory poll threads.
Search
the forum and/or CDI archives for a longer more detailed explaination of
why
the is REALLY BAD. Alternate:

NETTYPE ipcshm,4,64,CPU #One shm poll thr. for EVERY CPU VP (assuming 4 CPU
VP)!
NETTYPE tlitcp,3,96,NET #A reasonable but small number of NET VPs w/TCP
listener

Art S. Kagel

----- Original Message -----
From: Mueller Thomas <Thomas.Mueller@szm.de>
At: 2/21 5:00

> Hello,
>
> yes it's posssible to put several NETTYPEs in one file.
> I also have two entries in one file:
> NETTYPE tlitcp,4,96,CPU # Configure poll thread(s) for nettype
> NETTYPE ipcshm,2,64,CPU # Configure poll thread(s) for nettype
>
> ciao,
> Thomas
>
> -----Ursprungliche Nachricht-----
> Von: EDMUND LAJARA [mailto:edmund.lajara@nokia.com]
> Gesendet: Freitag, 21. Februar 2003 09:34
> An: ids@iiug.org
> Betreff: NETTYPE [453]
>
>
> I would just like to clarify on the setting of NETTYPE on the ONCONFIG.
Can I
> put several NETTYPEs on the one file, like:
>
> NETTYPE ipcshm,3,,CPU
> NETTYPE soctcp,,20,NET
>
> because I use the DBSERVERNAME and the DBSERVERALIASES with different
> connections? I wasn't so clear to me in the manual if I could have more
than
one
> entry (not like the VPCLASS where it explicitly says you can have several
> entries on the one onconfig). In case it is not possible, which one do I
put
for
> the NETTYPE?

Messages In This Thread

• Re: AW: NETTYPE
  ART KAGEL, BLOOMBERG/ 65E 55TH -- Friday, 21 February 2003, at 8:18 a.m.
  • Re: AW: NETTYPE
    dan.michaelis@verizon.com -- Friday, 21 February 2003, at 2:08 p.m.
    • Re: AW: NETTYPE
      Madison Pruet -- Monday, 24 February 2003, at 10:46 p.m.

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