Question about miss/hit ratio on some params

[GKramer]

Hi,
Using the followings script gives an overview of some miss/hit ratio on some parameters. What has happened with dc_table_scns and dc_qmc_cache_entries?? Who can tell me more about these two params and expain me how to deal with them??

select parameter,
gets,
getmisses,
round(getmisses/(gets+getmisses)*100,5) "miss ratio",
round((1-(sum(getmisses)/(sum(gets)+sum(getmisses)))
*100,5) "hit ratio"
from v$rowcache
where gets+getmisses <> 0
group by parameter, gets, getmisses



results;

PARAMETER GETS GETMISSES miss ratio hit ratio
-------------------------------------------------------------------------------------
dc_files 813 10 1.21507 98.78493
dc_users 114858 21 .01828 99.98172
dc_objects 503592 1365 .27032 99.72968
dc_profiles 6208 1 .01611 99.98389
dc_segments 1085755 1115 .10259 99.89741
dc_sequences 660 5 .75188 99.24812
dc_usernames 70449 32 .0454 99.9546
dc_object_ids 1046252 1072 .10236 99.89764
dc_table_scns 1 1 50 50
dc_global_oids 25624 147 .57041 99.42959
dc_tablespaces 19715 12 .06083 99.93917
dc_user_grants 8797 16 .18155 99.81845
dc_histogram_defs 3886 684 14.96718 85.03282
dc_qmc_cache_entries 1 1 50 50
dc_rollback_segments 48721 11 .02257 99.97743
dc_tablespace_quotas 233 1 .42735 99.57265


Regards, GKramer.

[nir_s]

Hi GKramer,
There isn't anything you can do to increase memory specifically for the dictionary cache.
The DC* parameters from V7 are dynamicly tuned by Oracle.

Regards,
Nir