PGA的使用到底受什么限制，是pga_aggregate_target吗？答案是否定的，根据TOM的说法，做了如下测试：
SQL> create or replace package demo_pkg
as
type array is table of char(2000) index by binary_integer;
g_data array;
end;
/ 2 3 4 5 6
Package created.
SQL> select a.name, to_char(b.value, '999,999,999') value
from v$statname a, v$mystat b
where a.statistic# = b.statistic#
and a.name like '%ga memory%';
2 3 4
NAME VALUE
---------------------------------------------------------------- ------------
session uga memory 1,609,968
session uga memory max 1,609,968
session pga memory 2,485,844
session pga memory max 20,246,100
SQL> begin
for i in 1 .. 100000
loop
demo_pkg.g_data(i) := 'x';
end loop;
end;
/ 2 3 4 5 6 7
PL/SQL procedure successfully completed.
SQL> select a.name, to_char(b.value, '999,999,999') value
from v$statname a, v$mystat b
where a.statistic# = b.statistic#
and a.name like '%ga memory%'; 2 3 4
NAME VALUE
---------------------------------------------------------------- ------------
session uga memory 313,349,536
session uga memory max 313,349,536
session pga memory 314,437,204
session pga memory max 314,437,204
SQL> show parameter pga_agg
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
pga_aggregate_target big integer 100M
显然，PGA的使用值已经远远超过了pga_aggregate_target参数设定的值，pga_aggregate_target所设置的大小，只是一个意向值而已。
来自 “ ITPUB博客 ” ，链接：http://blog.itpub.net/10972173/viewspace-524636/，如需转载，请注明出处，否则将追究法律责任。
