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Common Cause for ORA-4031 in 10gR2, Excess "KGH: NO ACCESS" Memory Allocation [Video] (Doc ID 801787.1)

Last updated on JUNE 09, 2023

Applies to:

Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database - Enterprise Edition - Version to [Release 10.2]
Oracle Database Cloud Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Information in this document applies to any platform.


After several hours of database operation, ORA-4031 errors are reported.

An examination of the ORA-4031 trace file will show the Memory Allocation called "KGH: NO ACCESS" is consuming large amount of memory. For example the following shows over 500Mbytes  for this allocation. 

Allocation Name             Size   
_________________________   __________
"free memory            "   163766600  
"KGH: NO ACCESS         "   560713888

Note that it is normal to periodically see "KGH: NO ACCESS" allocations up to about 64M.
This is memory that is in transition between SGA components when automatic memory management is resizing SGA components.  However, it is not normal to see persistent high allocations or a steady build up of this allocation type over time. The exception is when the database needs to make large changes i.e. when changing memory after a heavy load, or starting up using sub-optimal SGA settings, such as when an SPFILE is not being used.

The following query confirms that Memory Allocation "KGH: NO ACCESS" is large: 




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