###这时我们另开一个会话，select 5/60683 这个块
---session 2：select之前我们通过x$bh发现BA=07000001084A2000这行的FLAG变成了35651584，表示这个block的内容虽然还未提交但是已经flush到磁盘了
SYS@tstdb1-SQL> select obj,indx,addr,hladdr,flag,lru_flag,class,state,dbarfil,dbablk,ba,tch from x$bh where obj=41231;
OBJ INDX ADDR HLADDR FLAG LRU_FLAG CLASS STATE DBARFIL DBABLK BA TCH
---------- ---------- ---------------- ---------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------------- ----------
41231 31284 000000011099BA50 07000001B6B503D8 35651584 0 4 1 5 60682 070000014A920000 3
41231 147564 000000011099BA50 07000001B6C811F8 35651584 0 9 1 5 60681 07000000F4010000 1
41231 219327 000000011099BA50 07000001B6D3F4F0 35651584 0 1 1 5 60683 07000001084A2000 1
41231 219328 000000011099B908 07000001B6D3F4F0 524288 2 1 3 5 60683 0700000162014000 1
41231 280277 000000011099BA50 07000001B6DB20E0 35651584 0 8 1 5 60680 0700000102904000 1
***发起select操作
SYS@tstdb1-SQL> select * from scott.t1118_1 where username='SYS';
USERNAME USER_ID CREATED
------------------------------ ---------- -----------------
SYS 0 20141110 21:16:12
SYS@tstdb1-SQL> select obj,indx,addr,hladdr,flag,lru_flag,class,state,dbarfil,dbablk,ba,tch from x$bh where obj=41231;
OBJ INDX ADDR HLADDR FLAG LRU_FLAG CLASS STATE DBARFIL DBABLK BA TCH
---------- ---------- ---------------- ---------------- ---------- ---------- ---------- ---------- ---------- ---------- ---------------- ----------
41231 31287 000000011099BA50 07000001B6B503D8 35651584 0 4 1 5 60682 070000014A920000 4
41231 147573 000000011099BA50 07000001B6C811F8 35651584 0 9 1 5 60681 07000000F4010000 1
41231 219340 000000011099BA50 07000001B6D3F4F0 524288 0 1 3 5 60683 0700000105276000 1
41231 219341 000000011099B908 07000001B6D3F4F0 35651585 0 1 1 5 60683 07000001084A2000 1
41231 219342 000000011099B7C0 07000001B6D3F4F0 524288 2 1 3 5 60683 0700000162014000 1
41231 280283 000000011099BA50 07000001B6DB20E0 35651584 0 8 1 5 60680 0700000102904000 1