ora_30036

ora_30036
哪位大侠见过这种错误！！！！

declare
v_aac001 varchar2(20);
v_aab001 varchar2(20);

cursor youbiao is
select trim(a.aac001),trim(a.aab001)
from ac20_k01 a,ac01_bak b where a.aac001=b.yiliao_geren;
begin
open youbiao;
loop
fetch youbiao into v_aac001,v_aab001;
update ac20_bak set yiliao_geren=v_aac001,yiliao_danwei=v_aab001;
exit when youbiao%notfound;
end loop;
close youbiao;
end;

执行上面的游标后提示下面的错误！！！！

ORA-30036：无法按8192扩展段（在撤销表空间"UNDOTBS1"中）
ORA-06512：在line 31上


哪位高手给指点指点！！！

加大点呢？