研究一下x$bh，更加深入的了解一下buffer cache。

select /*+ ordered */
tot_bc_mem.TotBCMem,
decode(state,
  0,'Free',
  1,'Exclusive',
  2,'SharedCurrent',
  3,'ConsistentRead',
  4,'BeingRead',
  5,'InMediaRecoveryMode',
  6,'InInstanceRecoveryMode',
  7,'BeingWriten',
  8,'Pinned',
  9,'Memory',
  10,'Mrite',
  11,'Donated'
  ) "BlockDtate",
sum(blsiz) "SumStateTypeMem",
count(1) "NumOfBlksThisTyp",
round(sum(blsiz)/tot_bc_mem.TotBCMem,2)*100||'%' "PctTotBCMem"
from (select sum(blsiz) TotBCMem
from x$bh) tot_bc_mem,
x$bh
group by tot_bc_mem.TotBCMem,
  decode(state,
  0,'Free',
  1,'Exclusive',
  2,'SharedCurrent',
  3,'ConsistentRead',
  4,'BeingRead',
  5,'InMediaRecoveryMode',
  6,'InInstanceRecoveryMode',
  7,'BeingWriten',
  8,'Pinned',
  9,'Memory',
  10,'Mrite',
  11,'Donated'
  )
order by sum(blsiz);

相老师，这个语句查出来的ConsistentRead是什么意思

  好深奥，看不懂

支持相老师！顶！