沒有數據庫備份的情況下,非常規對ORACLE 12C CDB數據庫進行恢復
熟悉dul的朋友都知道dul是通過file# 1 block 1的kcvfhrdb找到bootstarp$的segment header(其實kcvfhrdb就是bootstarp$ segment header的rdba地址),然後通過bootstarp$中存儲的相關sql找對一些基礎的基表對象(obj$,tab$,col$,seg$等),然後通過他們定位到具體的對象的segment記錄,從而通過segment找到extent分佈,然後按照extent恢復數據(如果丟失system的情況,是通過掃描來確定extent屬於哪個segment,然後恢復,該情況不在本次討論範圍之類)。在ORACLE 12C之前,一個實例最多都只有一個數據庫,也就是說,在一個完整的數據庫中只會存在一個bootstarp$,只要通過file# 1 block 1 定位到kcvfhrdb就可以讀取數據庫中的所有內容.但是從12C開始數據庫引入了CDB的概念,也就是在一個CDB數據庫中有了多個PDB數據庫,那這些PDB數據庫如果要編寫類似dul之類工具將如何恢復出來,這裏根據自己對於CDB的理解,先普及一些在CDB數據庫中和bootstarp$表有關知識
bootstarp$表在每個PDB中都存在,可以通過bbed證明
--查看pdb相關信息 SQL> show pdbs; CON_ID CON_NAME OPEN MODE RESTRICTED ---------- ------------------------------ ---------- ---------- 2 PDB$SEED READ ONLY NO 3 PDB1 MOUNTED 4 PDB2 READ WRITE NO 5 ORA11G MOUNTED SQL> select con_id,header_file,header_block from cdb_segments where segment_name='BOOTSTRAP$'; CON_ID HEADER_FILE HEADER_BLOCK ---------- ----------- ------------ 4 11 520 1 1 520 2 5 520 ----因爲有部分庫未read write,所以查詢cdb_segments未顯示 --file 1 RMAN> copy datafile 1 to '/tmp/system_01.dbf'; BBED> set block 1 BLOCK# 1 BBED> map File: /tmp/system_01.dbf (0) Block: 1 Dba:0x00000000 ------------------------------------------------------------ Data File Header struct kcvfh, 1112 bytes @0 ub4 tailchk @8188 BBED> p kcvfhrdb ub4 kcvfhrdb @96 0x00400208 SQL> select to_number('400208','xxxxxxxxxx') from dual; TO_NUMBER('400208','XXXXXXXXXX') -------------------------------- 4194824 SQL> select dbms_utility.data_block_address_block(4194824) "block", 2 dbms_utility.data_block_address_file(4194824) "file" from dual; block file ---------- ---------- 520 1 ----可以知道bootstarp$起點的rdba爲4194824,在rfile# 1 block# 520上 --file 11 RMAN> copy datafile 11 to '/tmp/system_11.dbf'; BBED> set filename '/tmp/system_11.dbf' FILENAME /tmp/system_11.dbf BBED> set block 1 BLOCK# 1 BBED> p kcvfhrdb ub4 kcvfhrdb @96 0x00400208 ---顯示的rdba地址完全與file# 1中的kcvfhrdb相同,也就是表示rfile# 1 block# 520 --驗證未mount pdb,並且從11.2.0.4升級到12.1.0.1 ASMCMD> cp system01.dbf /tmp/system_18.dbf copying +data/ora11g/system01.dbf -> /tmp/system_18.dbf BBED> set filename '/tmp/system_18.dbf' FILENAME /tmp/system_18.dbf BBED> set block 1 BLOCK# 1 BBED> p kcvfhrdb ub4 kcvfhrdb @96 0x0041ad40 SQL> select to_number('41ad40','xxxxxxxxx') from dual; TO_NUMBER('41AD40','XXXXXXXXX') ------------------------------- 4304192 SQL> select dbms_utility.data_block_address_block(4304192) "block", 2 dbms_utility.data_block_address_file(4304192) "file" from dual; block file ---------- ---------- 109888 1 ----可以知道bootstarp$起點的rdba爲4304192,在rfile# 1 block# 109888上
1.查詢contrainer$視圖確認bootstarp$
SQL> select a.con_id#, a.dbid, a.rdba, dbms_utility.data_block_address_file(a.rdba) "file", 2 dbms_utility.data_block_address_block(a.rdba) "block"from container$ a; CON_ID# DBID RDBA file block ---------- ---------- ---------- ---------- ---------- 1 1922813718 4194824 1 520 5 4211303690 4304192 1 109888 2 4048821679 4194824 1 520 4 3872456618 4194824 1 520 3 3313918585 4194824 1 520
通過上面的知識點,我們明確,在ORACLE 12C CDB設計理念中,爲了和12C之前的版本兼用(12C之前的版本可以通過PDB插入到CDB中),也爲了方便用戶在操作PDB時候和傳統數據庫一樣,沒有任何區別,所以它把每個PDB的rdba的計算方法認爲PDB內部的RELFILE#是從1開始(也就是說每個rdba都是相對於自己的pdb而言),所以這裏的contrainer$查詢出來的rdba的地址就比較好理解(並非是絕對文件號,而是相對文件號,即表示pdb的第一個數據文件[傳統的system01.dbf])
2.rdba中的file#和cdb中的file#關係
SQL> show con_name; CON_NAME ------------------------------ PDB2 SQL> select file#, RELFILE# from file$; FILE# RELFILE# ---------- ---------- 12 4 11 1 13 13 SQL> show con_name; CON_NAME ------------------------------ CDB$ROOT SQL> select file#, RELFILE# from file$; FILE# RELFILE# ---------- ---------- 1 1 3 3 5 6 6 2 4 4 6 rows selected.
通過這裏的分析,就可以清晰的知道當前的dul是完全可以處理ORACLE 12C的CDB數據庫.
3.dul恢復CDB中PDB數據
--在pdb中創建測試表 SQL> show pdbs; CON_ID CON_NAME OPEN MODE RESTRICTED ---------- ------------------------------ ---------- ---------- 2 PDB$SEED READ ONLY NO 3 PDB1 MOUNTED 4 PDB2 READ WRITE NO 5 ORA11G MOUNTED SQL> alter session set container=pdb2; Session altered. SQL> show con_name; CON_NAME ------------------------------ PDB2 SQL> show con_id CON_ID ------------------------------ 3 SQL> create user xff identified by xifenfei; User created. SQL> grant dba to xff; Grant succeeded. SQL> create table xff.t_xifenfei tablespace users 2 as select * from dba_objects; Table created. SQL> alter system checkpoint; System altered. SQL> select count(*) from xff.t_xifenfei; COUNT(*) ---------- 90756 --使用dul抽取數據 [oracle@xifenfei dul]$ ./dul Strictly Oracle Internal Use Only DUL: Warning: Recreating file "dul.log" Disk group DATA, dul group_cid 0 Discovered disk /dev/sdb as diskgroup DATA, disk number 0 size 20480 Mb File1 starts at 10, dul_disk_cid 0 DUL: Warning: Dictionary cache DC_ASM_EXTENTS is empty Probing for attributes in File9, the attribute directory, for disk group DATA attribute name "_extent_sizes", value "1 4 16" attribute name "_extent_counts", value "20000 20000 214748367" Oracle data file size 283123712 bytes, block size 8192 Found db_id = 1922813718 Found db_name = CDB Oracle data file size 713039872 bytes, block size 8192 DUL> bootstrap; Probing file = 1, block = 520 . unloading table BOOTSTRAP$ DUL: Warning: block number is non zero but marked deferred trying to process it anyhow 60 rows unloaded DUL: Warning: Dictionary cache DC_BOOTSTRAP is empty Reading BOOTSTRAP.dat 60 entries loaded Parsing Bootstrap$ contents DUL: Warning: Recreating file "dict.ddl" Generating dict.ddl for version 11 OBJ$: segobjno 18, file 1 block 240 TAB$: segobjno 2, tabno 1, file 1 block 144 COL$: segobjno 2, tabno 5, file 1 block 144 USER$: segobjno 10, tabno 1, file 1 block 208 Running generated file "@dict.ddl" to unload the dictionary tables . unloading table OBJ$ 90758 rows unloaded . unloading table TAB$ 2363 rows unloaded . unloading table COL$ 106731 rows unloaded . unloading table USER$ 124 rows unloaded Reading USER.dat 124 entries loaded Reading OBJ.dat 90758 entries loaded and sorted 90758 entries Reading TAB.dat 2363 entries loaded Reading COL.dat 106685 entries loaded and sorted 106685 entries Reading BOOTSTRAP.dat 60 entries loaded DUL: Warning: Recreating file "dict.ddl" Generating dict.ddl for version 11 OBJ$: segobjno 18, file 1 block 240 TAB$: segobjno 2, tabno 1, file 1 block 144 COL$: segobjno 2, tabno 5, file 1 block 144 USER$: segobjno 10, tabno 1, file 1 block 208 TABPART$: segobjno 692, file 1 block 4528 INDPART$: segobjno 697, file 1 block 4568 TABCOMPART$: segobjno 714, file 1 block 9880 INDCOMPART$: segobjno 719, file 0 block 0 TABSUBPART$: segobjno 704, file 1 block 9928 INDSUBPART$: segobjno 709, file 0 block 0 IND$: segobjno 2, tabno 3, file 1 block 144 ICOL$: segobjno 2, tabno 4, file 1 block 144 LOB$: segobjno 2, tabno 6, file 1 block 144 COLTYPE$: segobjno 2, tabno 7, file 1 block 144 TYPE$: segobjno 619, tabno 1, file 1 block 1528 COLLECTION$: segobjno 619, tabno 2, file 1 block 1528 ATTRIBUTE$: segobjno 619, tabno 3, file 1 block 1528 LOBFRAG$: segobjno 725, file 1 block 4616 LOBCOMPPART$: segobjno 728, file 0 block 0 UNDO$: segobjno 15, file 1 block 224 TS$: segobjno 6, tabno 2, file 1 block 176 PROPS$: segobjno 126, file 1 block 1096 Running generated file "@dict.ddl" to unload the dictionary tables . unloading table OBJ$ DUL: Warning: Recreating file "OBJ.ctl" 90758 rows unloaded . unloading table TAB$ DUL: Warning: Recreating file "TAB.ctl" 2363 rows unloaded . unloading table COL$ DUL: Warning: Recreating file "COL.ctl" 106731 rows unloaded . unloading table USER$ DUL: Warning: Recreating file "USER.ctl" 124 rows unloaded . unloading table TABPART$ 234 rows unloaded . unloading table INDPART$ 155 rows unloaded . unloading table TABCOMPART$ 1 row unloaded DUL: Error: dc_segment_header(dataobj#=719, ts#=0, fil=0, blk=0) failed DUL: Warning: Nothing to unload from empty delayed segment creation table INDCOMPART$ . unloading table TABSUBPART$ 32 rows unloaded DUL: Error: dc_segment_header(dataobj#=709, ts#=0, fil=0, blk=0) failed DUL: Warning: Nothing to unload from empty delayed segment creation table INDSUBPART$ . unloading table IND$ 4237 rows unloaded . unloading table ICOL$ 6290 rows unloaded . unloading table LOB$ 849 rows unloaded . unloading table COLTYPE$ 2567 rows unloaded . unloading table TYPE$ 3651 rows unloaded . unloading table COLLECTION$ 1345 rows unloaded . unloading table ATTRIBUTE$ 13755 rows unloaded . unloading table LOBFRAG$ 6 rows unloaded DUL: Error: dc_segment_header(dataobj#=728, ts#=0, fil=0, blk=0) failed DUL: Warning: Nothing to unload from empty delayed segment creation table LOBCOMPPART$ . unloading table UNDO$ 1 row unloaded . unloading table TS$ 4 rows unloaded . unloading table PROPS$ 38 rows unloaded Reading USER.dat 124 entries loaded Reading OBJ.dat 90758 entries loaded and sorted 90758 entries Reading TAB.dat 2363 entries loaded Reading COL.dat 106685 entries loaded and sorted 106685 entries Reading TABPART.dat 234 entries loaded and sorted 234 entries Reading TABCOMPART.dat 1 entries loaded and sorted 1 entries Reading TABSUBPART.dat 32 entries loaded and sorted 32 entries Reading INDPART.dat 155 entries loaded and sorted 155 entries Reading IND.dat 4237 entries loaded Reading LOB.dat 849 entries loaded Reading ICOL.dat 6290 entries loaded Reading COLTYPE.dat 2567 entries loaded Reading TYPE.dat 3651 entries loaded Reading ATTRIBUTE.dat 13755 entries loaded Reading COLLECTION.dat DUL: Warning: Increased the size of DC_COLLECTIONS from 1024 to 8192 entries 1345 entries loaded Reading BOOTSTRAP.dat 60 entries loaded Reading LOBFRAG.dat 6 entries loaded and sorted 6 entries Reading UNDO.dat 1 entries loaded Reading TS.dat 4 entries loaded Reading PROPS.dat 38 entries loaded Database character set is ZHS16GBK Database national character set is AL16UTF16 DUL> unload table xff.t_xifenfei; . unloading table T_XIFENFEI 90756 rows unloaded
4.覈對數據恢復的結果
SQL> create table xff.t_xifenfei_new as select * from xff.t_xifenfei where 1=0; Table created. [oracle@xifenfei dul]$ sqlldr xff/xifenfei@pdb2 control=XFF_T_XIFENFEI.ctl SQL*Loader: Release 12.1.0.1.0 - Production on Sun Jun 2 18:08:04 2013 Copyright (c) 1982, 2013, Oracle and/or its affiliates. All rights reserved. Path used: Conventional Commit point reached - logical record count 64 Commit point reached - logical record count 128 Commit point reached - logical record count 192 Commit point reached - logical record count 256 Commit point reached - logical record count 320 Commit point reached - logical record count 384 Commit point reached - logical record count 448 Commit point reached - logical record count 512 Commit point reached - logical record count 576 ………… Commit point reached - logical record count 90589 Commit point reached - logical record count 90653 Commit point reached - logical record count 90717 Commit point reached - logical record count 90756 Table "XFF"."T_XIFENFEI_NEW": 90756 Rows successfully loaded. Check the log file: XFF_T_XIFENFEI.log for more information about the load. SQL> select count(*) from xff.t_xifenfei_new; COUNT(*) ---------- 90756
通過分析12C的bootstarp$表分佈,和dul恢復數據庫原理,通過變動實現dul完美恢復CDB中的pdb數據
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最權威、專業的Oracle案例資源彙總之案例:Oracle dul數據挖掘 非常規對ORACLE 12C CDB數據庫進行恢復
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