Pinning objects

Question

hi all,
Good day...
DB version is 10.2.0.4 ..Shared pool size is 2.5G. How do i pin the right objects..? Am using the below script to spool those objects with loads >5 and executions >100000
select 'execute sys.dbms_shared_pool.keep(''' ||
       owner || '.' || name || ''','  ||
       decode(type, 'TRIGGER', '''R''', 'JAVA CLASS', '''JC''', 'SEQUENCE', '''Q''', '''P''') || ')' stmt
  from v$db_object_cache
where type in ( 'FUNCTION', 'PROCEDURE', 'PACKAGE', 'PACKAGE BODY', 'JAVA CLASS', 'TRIGGER', 'SEQUENCE')
   and kept <> 'YES'
   and owner not in ('SYS','SYSTEM')
   and ( loads >= &loads
      or executions >= &executions )
order by loads, executions;
spool off;But i do have a pinning object list which is taken during the implementation and dont know on what metrics that file is spooled. But when i pin the objects taken from the above sql..i could see concurrent programs taking a bit more time to complete..How do i pin the right and needed objects?
thanks,
baskar.l

Answer 1

There are two purposes of pinning objects in SGA
1. To avoid out of memory error (Due to fragmentation, large object could not be loaded as it does not find continuous memory large enough to accommodate it).
2. To avoid the reload of objects.
So from this it is obvious that we should pin only frequently used large objects. If we pin many more objects then only a smaller amount of memory will be left for the remaining of the objects. This will result in high reload activity affecting the performance.
- Dinesh