(1)data dictionary cache hit ratio
     select * from v$rowcache
     select sum(gets)/(sum(gets)+sum(getmisses)) from v$rowcache where gets+getmisses<>0

(2)individual row cache parameter hit ratio
     select parameter,gets,getmisses,modifications,flushes,(gets/(gets+getmisses))*100 hisratio
     from v$rowcache where gets+getmisses>0

(3) library cache hit ratio
      select * from v$librarycache
      select * from v$library_cache_memory
      select sum(pins),sum(reloads),sum(pins)/(sum(pins)+sum(reloads)) from v$librarycache     --命中率

(4)individual library cache parameter hit radtio
      select namespace, pins, pinhits, pinhitratio, reloads, reloads
      /decode(pins,0,1,pins) reloadratio
       from v$librarycache

(5) Using the X$KSMSP Table to Get a Detailed Look at the Shared Pool
      select sum(ksmchsiz) size,ksmchcls status from x$ksmsp group by ksmchcls
      Status         Possible Meaning
      Free             This is the amount of contiguous free memory available.
      Freeabl        Freeable but not flushable shared memory; currently in use.
      Perm            I have read that this is permanently allocated and non-freeable memory,
                            but in testing this, I find that it behaves as free memory not yet moved to
                            the free area for use.
      Recr              Allocated memory that is flushable when the shared pool is low on memory.
      R-free           This is SHARED_POOL_RESERVED_SIZE (default 5 percent of SP).
      R-freea        This is probably reserved memory that is freeable but not flushable.
      R-recr           Recreatable chucks of memory in the reserved pool.
      R-perm        Permanent chucks of memory in the reserved pool.