ASMM - DB_KEEP_CACHE_SIZE

Question

Hello colleagues
10.2.0.2 - MS2003 SP2
I'm using ASMM and I like to pin a frequently scanned table to the KEEP buffer. The parameter DB_KEEP_CACHE_SIZE is per default 0. Do I have to change this parameter to the size of the object (at least) I like to pin?
If I set a fixed size of e.g. 200M - is this space allocated as one piece and not used anymore by other SGA components or is the "unused" space still available?
How can I prove that my object is located in the KEEP cache?
Thx for your hints.
TonyDBA

Answer 1

Hello colleagues
10.2.0.2 - MS2003 SP2
I'm using ASMM and I like to pin a frequently scanned table to the KEEP buffer. The parameter DB_KEEP_CACHE_SIZE is per default 0. Do I have to change this parameter to the size of the object (at least) I like to pin?
If I set a fixed size of e.g. 200M - is this space allocated as one piece and not used anymore by other SGA components or is the "unused" space still available?
How can I prove that my object is located in the KEEP cache?
Thx for your hints.
TonyDBA
Keep buffer usually to keep small, almost never updated table which used as look up table.
Set DB_KEEP_CACHE_SIZE size big enough to keep the table. Memory allocated for DB_KEEP_CACHE_SIZE will not be used by other component of SGA.
Use below query to check the tables that sitting on buffer cache:
select
object_name c1,
object_type c2,
num_blocks c3,
(num_blocks/decode(sum(blocks), 0, .001, sum(blocks)))*100 c4
from
(select
o.object_name object_name,
o.object_type object_type,
count(1) num_blocks
from
dba_objects o,
v$bh bh
where
o.object_id = bh.objd
and
o.owner not in ('SYS','SYSTEM')
group by
o.object_name,
o.object_type)
t1,
dba_segments s
where
s.segment_name = t1.object_name
and
num_blocks > 10
group by
object_name,
object_type,
num_blocks
order by
num_blocks desc
regards
AM