Memory Notification: Library Cache Object loaded into SGA问题-优快云博客

本文介绍如何调整Oracle 10g中关于Library Cache对象加载到SGA时的内存通知警告阈值。通过修改_kgl_large_heap_warning_threshold参数可以减少不必要的警告信息。文中还提供了设置步骤及注意事项。

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问题1:alert_SID.log出现

Memory Notification: Library Cache Object loaded into SGA

Heap size 2289K exceeds notification threshold (2048K)

Oracle10g中，在load较大的对象进library cache中时，会记录以上警告。在版本10.2.0.1中，这个定义大对象的阈值是2M，这是有隐含参数_kgl_large_heap_warning_threshold 指定的，如果系统中需要load很多大对象，又不想在alert中看到太多这类的警告信息，可以修改该参数：

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

参数值以字节为单位，设置完后需要重启实例才能生效。

从10.2.0.2起，这个参数的默认值被修改为50M.

下面是oracle上的metalink信息：

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, please contact Oracle Support Services for further investigation of any possible shared pool problems.