Library Cache Miss Ratio is High

[Shestakov]

birdax1 describe first and most probable problem with Library Cache.
next (not last) problem is number of "reloads" of objects.
u can check it :

select namespace, reload from v$librarycache;
or
select owner,name,loads,executions from v$db_object_cache;
--
-- where loads > xx
-- or
-- where executions - loads > xxx
--