[20161114]File Space Bitmap Block修复机制2.txt
--前几天在测试File Space Bitmap Block时执行了，execute dbms_space_admin.TABLESPACE_REBUILD_BITMAPS('SUGAR')
--这样位图区全部设置为1,显示都是F。
--上次提到，execute dbms_space_admin.TABLESPACE_REBUILD_BITMAPS('SUGAR')会修改位图区全部设置为1，显示都是F。
--而内存中相应数据块是正确的，只要执行alter system checkpoint;就会"纠正这个错误".我还做了1个极端测试，就是
--execute dbms_space_admin.TABLESPACE_REBUILD_BITMAPS('SUGAR')后，另外一个会话强制执行shutdown abort。
--测试这个时候备份的情况，忘记先drop表了，补充测试.
1.环境：
SCOTT@book> @ &r/ver1
PORT_STRING VERSION BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx 11.2.0.4.0 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
CREATE TABLESPACE SUGAR DATAFILE
'/mnt/ramdisk/book/sugar01.dbf' SIZE 40M AUTOEXTEND ON NEXT 16M MAXSIZE UNLIMITED
LOGGING
ONLINE
EXTENT MANAGEMENT LOCAL AUTOALLOCATE
BLOCKSIZE 8K
SEGMENT SPACE MANAGEMENT AUTO
FLASHBACK ON;
create table t1 tablespace sugar as select rownum id ,lpad('A',32,'A') name from dual connect by level<=1e5;
--建立大小5M的表。
create table t2 tablespace sugar as select rownum id ,lpad('B',32,'B') name from dual connect by level<=2e5;
create table t3 tablespace sugar as select rownum id ,lpad('C',32,'C') name from dual connect by level<=2e5;
alter system checkpoint;
2.做一个极端测试:
drop table t1 purge ;
drop table t2 purge ;
drop table t3 purge ;
SYS@book> execute dbms_space_admin.TABLESPACE_REBUILD_BITMAPS('SUGAR');
PL/SQL procedure successfully completed.
SYS@book> shutdown abort
ORACLE instance shut down.
$ bvi -b 24576 -s 8192 /mnt/ramdisk/book/sugar01.dbf
00006000 1E A2 00 00 03 00 80 01 55 46 62 00 00 00 01 04 79 41 00 00 06 00 00 00 80 00 00 00 00 00 00 00 ........UFb.....yA..............
00006020 00 F8 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF FF FF FF FF FF FF FF ................................
00006040 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................................
00006060 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................................
00006080 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................................
000060A0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................................
000060C0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................................
000060E0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................................
00006100 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................................
00006120 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF ................................
--可以发现是FF。然后重新启动数据库到mount状态。
SYS@book> startup mount
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
RMAN> backup datafile 6 format '/u01/backup/d6_A.bak' ;
Starting backup at 2016-11-14 14:56:06
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=1 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00006 name=/mnt/ramdisk/book/sugar01.dbf
channel ORA_DISK_1: starting piece 1 at 2016-11-14 14:56:07
channel ORA_DISK_1: finished piece 1 at 2016-11-14 14:56:08
piece handle=/u01/backup/d6_A.bak tag=TAG20161114T145607 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 2016-11-14 14:56:08
$ ls -l /u01/backup/d6_A.bak
-rw-r----- 1 oracle oinstall 26066944 2016-11-14 14:56:07 /u01/backup/d6_A.bak
--大小26066944/1024/1024=24.859375M,可以发现备份时依赖这个位图区扫描。
--注：前面的分析有误，感谢别人纠正这个错误，做测试太不严谨了，我前面的测试实际上oracle对null block是不备份的的。
$ strings /u01/backup/d6_A.bak | grep 'AAAAAAAAAAAAA' |wc
100000 170040 3624269
$ strings /u01/backup/d6_A.bak | grep 'BBBBBBBBBBBBB' |wc
200000 340080 7243655
$ strings /u01/backup/d6_A.bak | grep 'CCCCCCCCCCCCC' |wc
200000 340080 7243655
SYS@book> alter database open ;
Database altered.
SYS@book> alter system checkpoint;
System altered.
$ bvi -b 24576 -s 8192 /mnt/ramdisk/book/sugar01.dbf
00006000 1E A2 00 00 03 00 80 01 57 46 62 00 00 00 01 04 79 41 00 00 06 00 00 00 80 00 00 00 00 00 00 00 ........WFb.....yA..............
00006020 00 00 00 00 00 F8 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................................
00006040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................................
00006060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................................
00006080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................................
000060A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................................
000060C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................................
000060E0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................................
--很奇怪这次位图区修复了。是否drop table t1 purge时没有写盘。重复测试在drop完成后加入检查点，这样建表是没有问题的。
RMAN> backup datafile 6 format '/u01/backup/d6_B.bak' ;
Starting backup at 2016-11-14 15:03:06
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=1 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00006 name=/mnt/ramdisk/book/sugar01.dbf
channel ORA_DISK_1: starting piece 1 at 2016-11-14 15:03:07
channel ORA_DISK_1: finished piece 1 at 2016-11-14 15:03:08
piece handle=/u01/backup/d6_B.bak tag=TAG20161114T150306 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 2016-11-14 15:03:08
$ ls -l /u01/backup/d6_B.bak
-rw-r----- 1 oracle oinstall 1089536 2016-11-14 15:03:07 /u01/backup/d6_B.bak
--可以发现这次备份不仅仅1M上下。
SCOTT@book> create table t4 tablespace sugar as select rownum id ,lpad('D',32,'D') name from dual connect by level<=1e5;
Table created.
3.重新测试再drop后加入检查点：
--步骤参考上面。仅仅在drop后加入alter system checkpoint;
--建立表空间，建表t1,t2,t3,
drop table t1 purge ;
drop table t2 purge ;
drop table t3 purge ;
alter system checkpoint;
SYS@book> execute dbms_space_admin.TABLESPACE_REBUILD_BITMAPS('SUGAR');
PL/SQL procedure successfully completed.
SYS@book> shutdown abort
ORACLE instance shut down.
--
SYS@book> startup
ORACLE instance started.
Total System Global Area 634732544 bytes
Fixed Size 2255792 bytes
Variable Size 197133392 bytes
Database Buffers 427819008 bytes
Redo Buffers 7524352 bytes
Database mounted.
Database opened.
SCOTT@book> create table t4 tablespace sugar as select rownum id ,lpad('D',32,'D') name from dual connect by level<=1e5;
create table t4 tablespace sugar as select rownum id ,lpad('D',32,'D') name from dual connect by level<=1e5
*
ERROR at line 1:
ORA-00600: internal error code, arguments: [ktfbbssearch-9], [0], [624], [63488], [], [], [], [], [], [], [], []
--确实如此。
RMAN> backup datafile 6 format '/u01/backup/d6_C.bak' ;
Starting backup at 2016-11-14 15:23:58
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=46 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00006 name=/mnt/ramdisk/book/sugar01.dbf
channel ORA_DISK_1: starting piece 1 at 2016-11-14 15:23:59
channel ORA_DISK_1: finished piece 1 at 2016-11-14 15:24:00
piece handle=/u01/backup/d6_C.bak tag=TAG20161114T152359 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 2016-11-14 15:24:00
$ ls -l /u01/backup/d6_C.bak
-rw-r----- 1 oracle oinstall 26066944 2016-11-14 15:24:00 /u01/backup/d6_C.bak
--可以发现备份达到25M。
SYS@book> execute dbms_space_admin.TABLESPACE_REBUILD_BITMAPS('SUGAR');
PL/SQL procedure successfully completed.
RMAN> backup datafile 6 format '/u01/backup/d6_D.bak' ;
Starting backup at 2016-11-14 15:25:05
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00006 name=/mnt/ramdisk/book/sugar01.dbf
channel ORA_DISK_1: starting piece 1 at 2016-11-14 15:25:05
channel ORA_DISK_1: finished piece 1 at 2016-11-14 15:25:06
piece handle=/u01/backup/d6_D.bak tag=TAG20161114T152505 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 2016-11-14 15:25:06
$ ls -l /u01/backup/d6_D.bak
-rw-r----- 1 oracle oinstall 1089536 2016-11-14 15:25:05 /u01/backup/d6_D.bak
--修复后一切正常，再次说明备份通过读取数据文件的问题信息，确定读取的数据块。而前一次测试存在错误。