Hi :
I did run the following program(from metalink) in 8i (2 node OPS)
during peak hours and it says shared_pool utilization is 165%. Do I
have to increase the shared_pool_size to improve the performance?
DOC>* *
DOC>* TITLE : Shared Pool Estimation *
DOC>* CATEGORY : Information, Utility *
DOC>* SUBJECT AREA : Shared Pool *
DOC>* DESCRIPTION : Estimates shared pool utilization *
DOC>* based on current database usage. This should be *
DOC>* run during peak operation, after all stored *
DOC>* objects i.e. packages, views have been loaded. *
DOC>* *
DOC>* *
DOC>********************************************************/
Obj mem: 420192059 bytes
Shared sql: 404843921 bytes
Cursors: 2170375 bytes
Free memory: 76526336 bytes (72.98MB)
Shared pool utilization (total): 992647626 bytes (946.66MB)
Shared pool allocation (actual): 600000000 bytes (572.2MB)
Percentage Utilized: 165%
PL/SQL procedure successfully completed.
The program I used to get the above output:
set serveroutput on;
declare
object_mem number;
shared_sql number;
cursor_mem number;
mts_mem number;
used_pool_size number;
free_mem number;
pool_size varchar2(512); -- same as V$PARAMETER.VALUE
begin
- Stored objects (packages, views)
select sum(sharable_mem) into object_mem from v$db_object_cache;
- Shared SQL -- need to have additional memory if dynamic SQL used
select sum(sharable_mem) into shared_sql from v$sqlarea;
- User Cursor Usage -- run this during peak usage.
- assumes 250 bytes per open cursor, for each concurrent user.
select sum(250*users_opening) into cursor_mem from v$sqlarea;
- For a test system -- get usage for one user, multiply by # users
- select (250 * value) bytes_per_user
- from v$sesstat s, v$statname n
- where s.statistic# = n.statistic#
- and n.name = 'opened cursors current'
- and s.sid = 25; -- where 25 is the sid of the process
- MTS memory needed to hold session information for shared server
users
- This query computes a total for all currently logged on users (run
- during peak period). Alternatively calculate for a single user and
- multiply by # users.
select sum(value) into mts_mem from v$sesstat s, v$statname n
where s.statistic#=n.statistic#
and n.name='session uga memory max';
- Free (unused) memory in the SGA: gives an indication of how much
memory
- is being wasted out of the total allocated.
select sum(bytes) into free_mem from v$sgastat where name = 'free
memory';
- For non-MTS add up object, shared sql, cursors and 20% overhead.
used_pool_size := round(1.2*(object_mem+shared_sql+cursor_mem));
- For MTS mts contribution needs to be included (comment out previous
line)
- used_pool_size :=
round(1.2*(object_mem+shared_sql+cursor_mem+mts_mem));
select value into pool_size from v$parameter where
name='shared_pool_size';
- Display results
dbms_output.put_line ('Obj mem: '||to_char (object_mem) || ' bytes');
dbms_output.put_line ('Shared sql: '||to_char (shared_sql) || '
bytes');
dbms_output.put_line ('Cursors: '||to_char (cursor_mem) || ' bytes');
- dbms_output.put_line ('MTS session: '||to_char (mts_mem) || '
bytes');
dbms_output.put_line ('Free memory: '||to_char (free_mem) || ' bytes '
|| '('|| to_char(round(free_mem/1024/1024,2)) || 'MB)');
dbms_output.put_line ('Shared pool utilization (total): '||
to_char(used_pool_size) || ' bytes ' || '(' ||
to_char(round(used_pool_size/1024/1024,2)) || 'MB)');
dbms_output.put_line ('Shared pool allocation (actual): '|| pool_size
||' bytes ' || '(' || to_char(round(pool_size/1024/1024,2)) || 'MB)');
dbms_output.put_line ('Percentage Utilized:
'||to_char(round(used_pool_size/pool_size*100)) || '%');
end;
/
Thanks in advance
--Sami
--
http://www.freelists.org/webpage/oracle-l
Received on Sun Apr 10 2005 - 09:04:11 CDT
