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Wednesday, February 13, 2008

Memory Notification: Library Cache Object loaded into SGA

Memory Notification: Library Cache Object loaded into SGA

In 10g we have a new undocumented parameter that sets the KGL heap size warning threshold. This parameter was not present in 10gR1. Warnings are written if heap size exceeds this threshold.

Set _kgl_large_heap_warning_threshold to a reasonable high value or zero to prevent these warning messages. Value needs to be set in bytes.

If you want to set this to 8192 (8192 * 1024) and are using an spfile:

(logged in as "/ as sysdba")

SQL> alter system set "_kgl_large_heap_warning_threshold"=8388608 scope=spfile ;

SQL> shutdown immediate SQL> startup

SQL> show parameter _kgl_large_heap_warning_threshold
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
_kgl_large_heap_warning_threshold integer 8388608

If using an "old-style" init parameter,

Edit the init parameter file and add

_kgl_large_heap_warning_threshold=8388608

NOTE: The default threshold in 10.2.0.1 is 2M. So these messages could show up frequently in some application environments.

In 10.2.0.2, the threshold was increased to 50MB after regression tests, so this should be a reasonable and recommended value. If you continue to see the these warning messages in the alert log after applying 10.2.0.2 or higher, an SR may be in order to investigate if you are encountering a bug in the Shared Pool.


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