SAP

An easy way to speed up Data Reloads for SAP HANA on POWER - “tables_preloaded_in_parallel”

By Mark Short posted Mon June 28, 2021 12:35 PM

  

An easy way to leverage the superiority of the IBM POWER processor to greatly speed up the table load process during a tenant database restart operation is to increase the tables_preloaded_in_parallel configuration parameter.

For HANA v2 SPS05 rev56 or higher, the formula is the greater of 5 or (0.1 * CPU_THREADS); see SAP Note 3014176 - Applying System Size Dependent Resource Limits During Installation or Upgrade(https://launchpad.support.sap.com/#/notes/3014176).

For all tenant databases (indexserver.ini) on HANA v2 on Power, increase the "tables_preloaded_in_parallel" configuration parameter in HANA Studio to be a percentage of the number of lcpu on the LPAR. 


One way to find lcpu allocation is the lparstat command (you may have to run this as root):

# lparstat -l
System Configuration
type=Dedicated mode=Capped smt=8 lcpu=1024 mem=-17622 MB ent=128.00

When you restart the tenant database, you can see the number of parallel table loads being used in the indexserver*.trc file:
[9564]{-1}[12/-1] 2021-06-25 10:17:49.576252 i TableReload      TRexApiSystem.cpp(00665) : Now reloading 12284 tables (loading up to 75 tables in parallel)
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