IDS Forum

RE: max database connections

Posted By: Mark Tyrer
Date: Tuesday, 11 March 2008, at 5:19 a.m.

In Response To: RE: max database connections (Marcus Haarmann)

Hi,

The Maximum number of connections is limited by the amount of memory your
system has and also by the number of threads that your version of informix
supports. For informix versions 10 and 11, I know that there is an upper
limit of 32k threads supported,where each connection will use atleast one
thread. If you use PDQ then the number of threads per connection increases
and thus the number of connections available reduces. Informix increased
the number of threads from 8k to 32k so check your release notes for your
version of the database engine.

I would suspect however that you would need some serious memory on your box
should you start approaching anywhere near 32k connections. Also remember
that for TCP connections, Informix recommends at least one VP for every 250
connections. Again, there are memory considerations when increasing the
number of VPs

Regards Mark

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of Marcus
Haarmann
Sent: 11 March 2008 11:00 AM
To: ids@iiug.org
Subject: RE: max database connections [11570]

Hi,

You can only limit the number of database connections when using a shared
memory access. This is done using the nettype setting.
I think I remember a posting from Art Kagel a while ago in this group where
he described this already.
For other (mostly TCP) type of connections, there is no real limit in
connections.
I have seen servers running with more than 1000 connections in parallel on
one instance. And there could be more, if the machine is able to handle
this. The nettype parameter in this case has only effect on the internal
treatment of the connections (how many threads are started to handle the
connections).

Marcus

-----Original Message-----
From: WILL LANDSTROM [mailto:willlandstrom@yahoo.com]
Sent: Tuesday, March 11, 2008 7:23 AM
To: ids@iiug.org
Subject: max database connections [11567]

Hi everyone. Does anyone know how to determine with certainty what the
maximum number of database connections is for an IDS 9.4 database? Maybe I
am missing something but I am not seeing any onconfig parm that seems to
determine this.
Thanks.

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Forum Note: Use "Reply" to post a response in the discussion forum.

See you at the IIUG Informix 2008 Conference The Power Conference for
Informix Professionals April 27 - 30, 2008 Marriott Overland Park (Kansas
City), Kansas http://www.iiug.org/conf Registration Now Open!!

Messages In This Thread

• max database connections
  WILL LANDSTROM -- Tuesday, 11 March 2008, at 2:23 a.m.
  • RE: max database connections
    Marcus Haarmann -- Tuesday, 11 March 2008, at 4:59 a.m.
    • RE: max database connections
      Mark Tyrer -- Tuesday, 11 March 2008, at 5:19 a.m.

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