[Info-ingres] Memory Utilisation 98%

[Karl Schendel]

> On Sep 23, 2020, at 4:00 AM, Steve <s.anderson.au at gmail.com> wrote:
> 
>> On Thursday, September 10, 2020 at 12:18:04 PM UTC+10, Karl Schendel wrote:
>> 
>> I'd start by looking at the DMF buffer cache sizes / numbers to make sure that 
>> it's not overallocated.
> 
> Thanks Karl. Would I do that by setting trace point DM420 that Paul suggested?

Yes, or possibly easier, take a look at config.dat in $II_SYSTEM/ingres/files to see
what the cache settings are.  If you have a shared cache running, you might
see private cache settings in config.dat, just ignore those.

> 
>> The other step would be to use trace point SC916 
>> to print out the current sizes of the various ULM memory pools (these 
>> are the ones that grow). You can also use the DBMS log, if enabled, to 
>> see when the ULM pools grow.
> 
> Am I right to think most/all trace points can be set without needing to restart Ingres?

It depends, but yes you can use SC916 without restarting

> 
> Also, if the DBMS log is not enabled (i.e. II_DBMS_LOG is not set), am I right in thinking I must specify the log file using the SET TRACE OUTPUT statement? 
> 
> Is there any issue using the SET TRACE OUTPUT statement with multiple DBMS servers running? I see, for example, one can use %d and %p when setting II_DBMS_LOG.

Yes, you'll need to use SET TRACE OUTPUT.  That sets the DBMS log for the server you're
connected to, if you have multiple servers you'll want to arrange to connect to each of them.

> 
>> Finally, I'd make sure that you're looking at memory actually in use by 
>> the DBMS server, and not simply used as a file page cache. 
> 
> I am naively looking at the RSS figure returned by prstat -t (installation is running on Solaris).

Hmm, I've been away from Solaris too long, not sure if that will over-estimate or not.

You might try pmap and add up the mapped segment sizes, omitting shared libraries,
as a double check to see if prstat is in the right ballpark

> 
> In wanting to tweak the memory footprint of Ingres, it's not so much that there is a problem with Ingres, it's just that Ingres is the only thing under my control, the server is managed by another outfit.
> 
> Thanks
> Steve
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