SAP Hana - Used memory

Instant

SELECT ( 
       (
         CODE_SIZE 
         + SHARED_MEMORY_ALLOCATED_SIZE 
         + HEAP_MEMORY_USED_SIZE 
         ) / 1024 / 1024) AS "USED MEMORY"
FROM M_SERVICE_MEMORY

The overall allocated shared memory SHARED_MEMORY_ALLOCATED_SIZE is used for the calculation and not the value of SHARED_MEMORY_USED_SIZE. The reason for this is that the a shared memory segment can only be completely attached to the address space of the process and not just the used part.

• Single Summary by Host

select HOST, round(INSTANCE_TOTAL_MEMORY_USED_SIZE/1024/1024/1024, 2) as "Used Memory GB" from M_HOST_RESOURCE_UTILIZATION

• The indexserver holds all the data tables and temporary results, and therefore dominates the SAP HANA Used Memory. amount of indexserver Used Memory:

select HOST, round(TOTAL_MEMORY_USED_SIZE/1024/1024/1024, 2) as "Used Memory GB" from M_SERVICE_MEMORY where SERVICE_NAME = 'indexserver'

Over time

Used Memory over time to understand peak loads.

A snapshot copy of Used Memory is periodically saved in:

• the HOST_RESOURCE_UTILIZATION_STATISTICS system table,
• in the HOST_SERVICE_MEMORY (to examine memory usage by service)

• peak amount of Used Memory since the server was restarted:

select top 1 HOST, SERVER_TIMESTAMP, round(INSTANCE_TOTAL_MEMORY_USED_SIZE/1024/1024/1024, 2) as "Peak Used GB" from _SYS_STATISTICS.HOST_RESOURCE_UTILIZATION_STATISTICS order by "Peak Used GB" desc

• value of Used Memory at 7:00 AM during each of the last 30 days:

select top 30 HOST, SERVER_TIMESTAMP, round(INSTANCE_TOTAL_MEMORY_USED_SIZE/1024/1024/1024, 2) as "Used Memory GB" from _SYS_STATISTICS.HOST_RESOURCE_UTILIZATION_STATISTICS where hour(SERVER_TIMESTAMP) = 7 and minute(SERVER_TIMESTAMP) = 0 order by SERVER_TIMESTAMP desc