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Oracle RDBMS is not detecting NUMA Nodes (Doc ID 868642.1)

Last updated on MARCH 09, 2019

Applies to:

Oracle Database - Enterprise Edition - Version and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Linux x86
Linux x86-64
***Checked for relevance on 20-Sep-2016***


You are running on a NUMA capable Hardware and your Operating System is NUMA aware and well configured. You can check this by executing: 'numactl –hardware' OS command and obtaining an output like:

# numactl –hardware
available: 2 nodes (0-1)
node 0 size: 129009 MB
node 0 free: 57406 MB
node 1 size: 129027 MB
node 1 free: 111756 MB
node distances:
node   0   1
  0:  10  26
  1:  26  10

You have installed the fix for <> and you have set the required oracle init.ora (spfile) parameter '_enable_NUMA_optimization=TRUE' but your RDBMS is not detecting the NUMA characteristics of the machine. In the Alert.log you have just an entry like:

Opening with internal Resource Manager plan
where NUMA PG = 1, CPUs = 48

Having 'NUMA PG = 1' it means that your Oracle RDBMS is looking for just one Processor Group and then NUMA is disable. You should have Numa PG >1


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