IDS Forum

Re: Can Informix 9.40 UC7 use more than 2 GB of me

Posted By: MARK JALKIEWICZ
Date: Wednesday, 17 August 2011, at 3:36 p.m.

In Response To: Re: Can Informix 9.40 UC7 use more than 2 GB of me (rroussey@comcast.net)

You can, however on AIX you have to pay attention to boundary aligments which require segments (and all added segments, i.e. shmadd) be aligned on 262 meg boundary alignments. This is easily overlooked as you may wind up with memory allocation errors and find out you wasted accessing memory due to this requirement and attribute it to some limitation. However I would imagine you will bump up against some upper boundary limit with respect to 32 bit IDS.

In most likelihood you will wind up with a "gap" (wasted memory) between the Resident and the first Virtual segment since the Resident segment has to allow for LOCKS and BUFFERS and other internal structures which there is no easy formula for calculating unless your overly ambitious. However SHMVIRTSIZE should be equated to 262144 or multipile of. My suggestion is to test and see how much memory you can address after startup by issuing multipile onmode -a commands (remember the 256 meg alignment so equate SHMADD to 262144 or issue onmode -a 262144 ) and see how much memory you can address/allocate. Then run an onstat -g seg and see how the memory maps out. Other than the gap between the Resident and the first Virtual, all memory segments addresses should be contigious (address + size = next begin address).

If using shared memory connections,switch over to tcp as shem connections require a small portion of shared memory for the message segment , however aix will allocate a 262 meg seg.

Isn't 9.40 eos by now ?

Messages In This Thread

• Can Informix 9.40 UC7 use more than 2 GB of memory
  SCOTT YOHONN -- Wednesday, 17 August 2011, at 9:51 a.m.
  • Re: Can Informix 9.40 UC7 use more than 2 GB of me
    rroussey@comcast.net -- Wednesday, 17 August 2011, at 2:59 p.m.
    • Re: Can Informix 9.40 UC7 use more than 2 GB o....
      Marcus Haarmann -- Wednesday, 17 August 2011, at 3:29 p.m.
    • Re: Can Informix 9.40 UC7 use more than 2 GB of me
      MARK JALKIEWICZ -- Wednesday, 17 August 2011, at 3:36 p.m.

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