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Application Memory Leakage on OpenVMS 7.3-1

Occasional Visitor

Application Memory Leakage on OpenVMS 7.3-1

Hi All,

I have recently upgraded 4 servers running OpenVMS 7.1-2 & Oracle 8.0.5 to OpenVMS 7.3-1 & Oracle 9i.

I saw a steady increase in memory usage on 1 node, until utilization jumped from around 70% to 100%, which resulted in extensive system processes getting swapped out.

We narrowed the issue down to an image/process that has been leaking memory (not releasing) on a massive scale (consumption of around 1.2GB of physical memory from 160MB initially).

We know for a fact that there have not been any change to the image except for a recompilation/linking for it to run on OpenVMS 7.3-1.

The image is just a process relaying "requests" from the client (workstation) side to the Oracle database sitting on the OpenVMS server and vice-vesa other similar process do not have the same problems.

Question is:

1. Is there someone who has encountered similar problems after upgrading their OS version?

2. I know that the memory management on the 2 OS versions are quite different, so could these changes cause the image to behave so wierdly on the V7.3-1?

3. Are there any issue at the Database or netwoek level that I need to take a look at?

Your help is very much appreciated.

Michael Pin Harry
Karl Rohwedder
Honored Contributor

Re: Application Memory Leakage on OpenVMS 7.3-1

Did you check Metalink for patches/errors for your specific version? The phrase 'memory leak'
is quite often returned.
Daniel Fernandez Illan
Trusted Contributor

Re: Application Memory Leakage on OpenVMS 7.3-1

Hi Michael

I have updated several nodes from VMS 7.2.1 to VMS 7.3.1 and after to VMS 7.3.2., and I not finding problems as far as performances in the systems (my version of oracle is 8.1.7).
I think that the greater consumption of resources may be caused to the version of Oracle.
You may search in Metalink some information about Oracle 9i and the resources what it need.

Lawrence Czlapinski
Trusted Contributor

Re: Application Memory Leakage on OpenVMS 7.3-1

1. We upgraded five Alphas from OpenVMS Alpha 7.1-x to OpenVMS 7.3 and then to 7.3-1 or directly to OpenVMS 7.3-1 without any memory leakage.
2. Since the image was recompiled/relinked, leaking memory would not be expected but as you experienced it can happen. Most likely the image is not handling memory correctly.
3. As previously suggested, review available OS and application patches.
4. As a workaround, examine the number of working set pages actually being consumed by the offending image. Then as a workaround, in MODPARAMS.DAT, lower MAX_PQL_MSWEXTENT from the current PQL_MWSEXTENT to at least the maximum number of pages you want to allow the offending image. Setting it even lower would give you more flexibility since changing PQL_MWSEXTENT requires a reboot. If it is lower you could play with different values for the offending image without having to reboot the node. You will also need to explictly set the WSEXTENT for this process if it defaults to DWSEXTENT. Then do:
Then do a differences on SETPARAMS.DAT to see the new value of PQL_MSWEXTENT.
Schedule a time to reboot.
Reboot and observe system performance.
Daniel Fernandez Illan
Trusted Contributor

Re: Application Memory Leakage on OpenVMS 7.3-1


Also you can check this parameters:


This link may be help you: