Total size of SGA greater than what was allocated

Please note that we are running Oracle 7.3.4.4 under SCO UNIX 5.0.5. The allocated SGA is as following: 
 Total System Global Area    1064706136 bytes
 Fixed Size                       41880 bytes
 Variable Size                204623040 bytes
 Database Buffers             858992640 bytes
 Redo Buffers                   1048576 bytes
I observed that the behavior of the SGA is not acceptable because sometimes, when I execute the following query:
 SELECT SUM(BYTES)/1024/1024 FROM V$SGASTAT
 
 I get the total size of the SGA greater than what we
 allocated, and there is
 no free memory.
 
 Any ideas regarding this issue?

    Requires Free Membership to View

    Login 

 
V$SGASTAT does not include everything. For instance,
it does not include the "Fixed Size" of the SGA. So
you will see a difference between the SHOW SGA command
and the sum of bytes from V$SGASTAT. 


You should, however, see some free memory from
V$SGASTAT. For instance, use the following query:

SQL> select * from v$sgastat where name='free memory';

POOL        NAME                                 
BYTES
----------- --------------------------
----------------
shared pool free memory                      
7,062,044


Here, I have 7MB free in my Shared Pool. You don't
want a lot of free memory however since this will be
wasting space.

For More Information

 
 





This was first published in November 2002

Join the conversationComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.
    Back to top