Script: SGA Memory Pool Sizes

 with data
   as
   (
   select decode( grouping( pool ), 1, 'SGA total:', pool ) "Pool",
          sum(bytes) bytes
     from (select nvl(pool,'*'||name) pool, bytes from v$sgastat )
    group by rollup (pool)
   )
   select "Pool", bytes, round(bytes/1024/1024) mbytes
     from data
    union all
   select 'PGA target', v-bytes, round((v-bytes)/1024/1024)
     from data, (select to_number(value) v
                   from v$parameter
                              where name = 'memory_target')
    where "Pool" = 'total:'
 ;

Pool                                                            BYTES     MBYTES
---------------------------------------------------------- ---------- ----------
*buffer_cache                                              1.3288E+10      12672
*fixed_sga                                                    2119984          2
*log_buffer                                                 123863040        118
*shared_io_pool                                            1275068416       1216
java pool                                                    67108864         64
large pool                                                   67108864         64
shared pool                                                1008419096        962
streams pool                                                201335712        192
SGA total:                                                 1.6033E+10      15290