how to check Memory Usage in SAP HANA DATABASE

How to check Memory Usage detail in hHANA database using SQL query.

1- How to find out the top 100 memory usage in SAP HANA database between a specified time.

select top 100 round(TOTAL_MEMORY_USED_SIZE/1024/1024/1024, 2) as

"Used Memory GB", HOST, SERVER_TIMESTAMP  from _SYS_STATISTICS.HOST_SERVICE_MEMORY where SERVER_TIMESTAMP between '11.02.2017 02:00:00' and '19.06.2017 19:00:00' order by TOTAL_MEMORY_USED_SIZE desc

2- How to check the peak memory usage.

select top 1 HOST, SERVER_TIMESTAMP, round(TOTAL_MEMORY_USED_SIZE/1024/1024/1024, 2) as "Used Memory GB" from _SYS_STATISTICS.HOST_SERVICE_MEMORY where SERVICE_NAME = 'indexserver'

order by TOTAL_MEMORY_USED_SIZE desc

3- How to find the schema name, current memory usage, max memory usage (if all tables and all their columns were loaded into memory simultaneously) and record count in each schema .

select schema_name, round(sum(memory_size_in_total/1024/1024/1024),1) as "Current MEM GB", 

round(sum(estimated_max_memory_size_in_total/1024/1024/1024),1) as "MAX MEM GB", 

sum(record_count)  from "SYS"."M_CS_TABLES"  group by schema_name  order by "Current MEM GB" desc 

4- How to get the total table count in a HANA  schema.

SELECT  count(*) "TABLE_NAME" FROM "SYS"."M_TABLES" where "SCHEMA_NAME" = 'SAPABAP1'

5- How to get the total memory usage of a HANA schema.

Column tables details 

SELECT TABLE_NAME AS "Table",sum(round(MEMORY_SIZE_IN_TOTAL/1024/1024, 2)) as "MB" FROM  M_CS_TABLES WHERE SCHEMA_NAME = 'SAPABAP1'

Row tables details.

select round(sum(USED_FIXED_PART_SIZE + USED_VARIABLE_PART_SIZE)/1024/1024) as "Row Tables MB Used" from M_RS_TABLES where "SCHEMA_NAME" = 'SAPABAP1'