SAP HANA – System Appears to Hang with High System CPU Usage

The SAP HANA database is an in-memory database and by its nature, it consumes large amounts of memory. Therefore, some performance issues of SAP HANA can be caused by the OS’s memory management.
For this case, you can see high usage of SYSTEM CPU that can be monitored in the load graph, available from SAP HANA studioAdministrationPerformance

Root cause: Problem caused by the configuration of transparent huge page

Required action:

1.Check Transparent Huge Page whether it is set to [never] by running the command “cat /sys/kernel/mm/transparent_hugepage/enabled”

2.Apply KBA 2031375 – SAP HANA: Transparent HugePages (THP) setting on Linux

 

Root cause: Problem caused by the configuration of OS page cache

Required action:

1.Check sar file ( /var/log/sa ) whether kbcached usage ( sar -r ) is higher than 10% of physical memory and high page in/out occurred

2.Check and apply SAP Note 1557506 – Linux paging improvements

 

Root cause: Problem caused by translation lookaside buffer (TLB) shootdown

Required action:

1.Check plan trace. For more information, see SAP Note 2206354 SAP HANA DB: High System CPU Consumption Caused by Plan TraceRoot cause: Due to high context switches (High SYS CPU) by many SqlExecutor threads

1.Check load graph and indexserver.ini -> sql -> sql_executors / max_sql_executors and refer to Controlling Parallelism of SQL Statement Execution

 

Root Cause: Due to high context switches (High SYS CPU) by many JobExecutor threads.

Required action: Check that the following parameters are set to be bigger than the number of logical CPU cores1.
indexserver.ini -> parallel -> num_cores (<=SPS07) and refer to Controlling Parallelism of SQL Statement Execution2.
global.ini/indexserver.ini -> execution -> max_concurrency (>SPS08)

Reference :http://help.sap.com/hana/SAP_HANA_Troubleshooting_and_Performance_Analysis_Guide_en.pdf

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