怎样识别IO竞争和负载平衡

select
df.name 文件名,
fs.phyrds 读次数,
fs.phywrts 写次数,
(fs.readtim/decode(fs.phyrds,0,-1,fs.phyrds)) 读时间,
(fs.writetim/decode(fs.phywrts,0,-1,fs.phywrts)) 写时间
from
v$datafile df,
v$filestat fs
where df.file#=fs.file#
order by df.name