ITPub博客

首页 > 数据库 > 数据库开发技术 > Adding Granules and Tracking Component Size (78)

Adding Granules and Tracking Component Size (78)

原创 数据库开发技术 作者:tsinglee 时间:2007-10-23 15:16:33 0 删除 编辑

A database administrator expands the SGA use of a component with an ALTER
SYSTEM statement to modify the values of the initialization parameters associated
with the respective components. Oracle Database rounds up the newly specified size
to the nearest multiple of 16MB and adds or removes granules to meet the target size.
The database must have enough free granules to satisfy the request. As long as the
current amount of SGA memory is less than SGA_MAX_SIZE, the database can allocate
more granules until the SGA size reaches SGA_MAX_SIZE.
The granule size that is currently being used for the SGA for each component can be
viewed in the view V$SGAINFO. The size of each component and the time and type of
the last resize operation performed on each component can be viewed in the view
V$SGA_DYNAMIC_COMPONENTS. The database maintains a circular buffer of the last
400 resize operations made to SGA components. You can view the circular buffer in the
V$SGA_RESIZE_OPS view.
Note: If you specify a size for a component that is not a multiple of
granule size, then Oracle rounds the specified size up to the nearest
multiple. For example, if the granule size is 4 MB and you specify DB_
CACHE_SIZE as 10 MB, you will actually be allocated 12 MB.

通过alter system指定组件的大小时 , Oracle添加移除细粒度来达到目标值 ,如果指定的值
不是granule size的倍数 , Oracle将rounds the specified size up to the nearest
multiple .当总的sga内存小于SGA_MAX_SIZ时 ,数据库可以分配细粒度来达到该值 。
细粒度的值可以通过V$SGAINFO来查询 , 每个组件的值可以通过V$SGA_DYNAMIC_COMPONENTS ,
通过V$SGA_RESIZE_OPS视图可以查询sga组件的操作

[@more@]

来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/10599713/viewspace-978164/,如需转载,请注明出处,否则将追究法律责任。

请登录后发表评论 登录
全部评论
  • 博文量
    740
  • 访问量
    1892116