Library Cache Miss Ratio

Executions - The number of times a pin was requested for objects of this namespace.

Cache Misses - Any pin of an object that is not the first pin performed since the object handle was created, and which requires loading the object from disk.

Hit Ratio should be < 1%, else increase SHARED_POOL_SIZE in init.ora

select sum(PINS) Executions,  sum(RELOADS) cache_misses,
      sum(RELOADS) / sum(PINS) miss_ratio
from  v$librarycache