Difference between total resident and database resident > 2GB

[Former Member]

Dear All,

As per the SAP note 1840954 that difference between total resident and database resident memory should not be more than 2GB. However, for our HANA systems the difference is far more than 2GB.

Please note that we are licensed for only 64GB therefore global_allocation_limit is set to 90% of 64GB (as explained in SAP HANA Administration guide).

I thought that that value of database resident should be less than "Used Memory". Used memory is total amount of memory currently in use by SAP HANA i.e. Column tables + row tables + system tables + code& stack +  DB management. This is a concern but I am unable to find the cause.

Can someone please suggest on this?

Regards

Angad

[sunny_pahuja2]

Hello,

Please refer to SAP note 1698281 which will guide you how to assess memory consumption of HANA system.

Thanks,

Sunny

[Former Member]

Hi Sunny,

SAP note 1698281 is for BW on HANA system. We are using HANA as sidecar. Also, the SAP note 1840954 that I mention in my discussion talks more about HANA memory consumption and performance in general. I am referring to that note while monitoring and troubleshooting.

Please see my following reply from SAP support:

"We are suspecting that some memory (Pool/ihm) was not properly freed.

Fortunately, it is known issue and already fixed.

This looks same issue, but we should have check for more traces to

confirm that."

According to them this issue is fixed in Rev 69.01. They have asked for full system dump so we will be sending that soon. I will update this thread once issue is resolved.

Regards

Angad

[Former Member]

Have you ever got to know difference between difference between database resident & total resident memory. I went through a lot of documents & not yet found any difference.

Best Regards

Sachin

[Former Member]

Hi Sachin,

The only difference that I have found that total resident also consider shared memory.

As per note 1840954

'Database Resident':

SELECT SUM(PHYSICAL_MEMORY_SIZE) FROM M_SERVICE_MEMORY

'Total Resident':

SELECT T1.HOST, T1.USED_PHYSICAL_MEMORY + T2.SHARED_MEMORY_ALLOCATED_SIZE
FROM M_HOST_RESOURCE_UTILIZATION AS T1
JOIN (SELECT M_SERVICE_MEMORY.HOST, SUM(M_SERVICE_MEMORY.SHARED_MEMORY_ALLOCATED_SIZE) AS SHARED_MEMORY_ALLOCATED_SIZE
         FROM SYS.M_SERVICE_MEMORY 
         GROUP BY M_SERVICE_MEMORY.HOST) AS T2
ON T2.HOST = T1.HOST;

Regards

Angad