### 1. Oracle ASSM介绍 ```sql Oracle ASSM(Automatic Segment Space Managed)使用三级位图来管理数据库中的 空间,由于bbed工具不支持查询Segment Header的物理结构，造成Oracle dba无法深 入准确的查询位图结构及变化，本文借鉴bbed的展示方式，使用C语言完全解析 Oracle ASSM的三级位图结构，希望对各位有所帮助。解析结果如下所示， ``` ### 2. 测试数据创建 ```sql create table hsql.test1(t1 char(10),t2 char(10)) tablespace test1; insert into hsql.test1 values('1','a'); insert into hsql.test1 values('2','aa'); insert into hsql.test1 values('3','aaa'); insert into hsql.test1 values('4','aaaa'); insert into hsql.test1 values('5','aaaaa'); insert into hsql.test1 values('6','aaaaaa'); insert into hsql.test1 values('7','aaaaaaa'); insert into hsql.test1 values('8','aaaaaaaa'); insert into hsql.test1 values('9','aaaaaaaaa'); insert into hsql.test1 values('10','aaaaaaaaaa'); commit; select * from hsql.test1; begin for i in 1..10000 loop insert into hsql.test1 values(i,'a'||i); commit; end loop; end; / ``` ### 3. unload 导出业务数据 ```sql [oracle@sourcedb xdul]$ ./xdul xdul: Data Unload for Oracle version 1.1.1 Copyright(c) 2020 orastar.All rights reserved. Wechat: xidoublestr Email: 634025070@qq.com loading default config....... load config file 'config.txt' successful loading default control file ...... ts# fn rfn bsize blocks filename ---- ---- ---- ----- -------- -------------------------------------------- 0 1 1 8192 97280 /oradata/epmsn/system01.dbf 1 2 2 8192 89600 /oradata/epmsn/sysaux01.dbf 2 3 3 8192 8960 /oradata/epmsn/undotbs01.dbf 4 4 4 8192 640 /oradata/epmsn/users01.dbf 6 5 5 8192 12800 /oradata/epmsn/test1.dbf load control file 'control.txt' successful XDUL>list user; userid username ------ ---------- 0 SYS 1 PUBLIC 2 CONNECT 3 RESOURCE 4 DBA 5 SYSTEM 6 SELECT_CATALOG_ROLE 7 EXECUTE_CATALOG_ROLE 8 DELETE_CATALOG_ROLE 9 OUTLN 10 EXP_FULL_DATABASE 11 IMP_FULL_DATABASE 12 LOGSTDBY_ADMINISTRATOR 13 DBFS_ROLE 14 DIP 15 AQ_ADMINISTRATOR_ROLE 16 AQ_USER_ROLE 17 DATAPUMP_EXP_FULL_DATABASE 18 DATAPUMP_IMP_FULL_DATABASE 19 ADM_PARALLEL_EXECUTE_TASK 20 GATHER_SYSTEM_STATISTICS 21 ORACLE_OCM 22 RECOVERY_CATALOG_OWNER 23 SCHEDULER_ADMIN 24 HS_ADMIN_SELECT_ROLE 25 HS_ADMIN_EXECUTE_ROLE 26 HS_ADMIN_ROLE 27 GLOBAL_AQ_USER_ROLE 28 OEM_ADVISOR 29 OEM_MONITOR 30 DBSNMP 31 APPQOSSYS 32 WMSYS 33 WM_ADMIN_ROLE 34 JAVAUSERPRIV 35 JAVAIDPRIV 36 JAVASYSPRIV 37 JAVADEBUGPRIV 38 EJBCLIENT 39 JMXSERVER 40 JAVA_ADMIN 41 JAVA_DEPLOY 42 EXFSYS 43 CTXSYS 44 CTXAPP 45 XDB 46 ANONYMOUS 47 XDBADMIN 48 XDB_SET_INVOKER 49 AUTHENTICATEDUSER 50 XDB_WEBSERVICES 51 XDB_WEBSERVICES_WITH_PUBLIC 52 XDB_WEBSERVICES_OVER_HTTP 53 ORDSYS 54 ORDDATA 55 ORDPLUGINS 56 SI_INFORMTN_SCHEMA 2147483638 XS$NULL 57 MDSYS 58 ORDADMIN 59 OLAP_XS_ADMIN 60 OLAPSYS 61 OLAP_DBA 62 CWM_USER 63 OLAP_USER 64 MDDATA 65 SPATIAL_WFS_ADMIN 66 SPATIAL_WFS_ADMIN_USR 67 WFS_USR_ROLE 68 SPATIAL_CSW_ADMIN 69 SPATIAL_CSW_ADMIN_USR 70 CSW_USR_ROLE 71 SYSMAN 72 MGMT_USER 73 MGMT_VIEW 74 FLOWS_FILES 75 APEX_PUBLIC_USER 76 APEX_ADMINISTRATOR_ROLE 77 APEX_030200 78 OWBSYS 79 OWBSYS_AUDIT 80 OWB$CLIENT 81 OWB_DESIGNCENTER_VIEW 82 OWB_USER 83 SCOTT 84 HSQL 85 _NEXT_USER XDUL>set user; input username: HSQL cur_user: HSQL,cur_userid:84 XDUL>XDUL> XDUL>list table; OBJ#,DATAOBJ#,OWNER#,NAME,SUBNAME,ROWCNT,BLKCNT ------------------------------------------------------------ 88135,88135,84,TEST1,,10,5 88141,88142,84,TEST_DATE,,11,5 XDUL>desc input OBJ#: 88135 Name,Type ---------------------- T1,char(10) T2,char(10) XDUL>XDUL>unload table; input OBJ#: 88135 Unloading table: HSQL.TEST1,object ID: 88135 Unloading segment,storage(Obj#=88135 DataObj#=88135 TS#=6 File#=5 Block#=138 Cluster=0) --说明段头块为 File#=5 Block#=138 10010 rows unloaded XDUL> ``` ### 4. 格式化解析L3 BMB ```sql XDUL>bmb input fno: 5 input blk: 138 struct kcbh, 20 bytes @0 ub1 type_kcbh @0 0x23 ub1 frmt_kcbh @1 0xa2 ub1 spare1_kcbh @2 0x00 ub1 spare2_kcbh @3 0x00 ub4 rdba_kcbh @4 0x0140008a ub4 bas_kcbh @8 0x002508bc ub2 wrp_kcbh @12 0x0000 ub1 seq_kcbh @14 0x03 ub1 flg_kcbh @15 0x04 ub2 chkval_kcbh @16 0xf230 ub2 spare3_kcbh @18 0x0000 struct ech(Extent Control Header) @36 ub4 extents_ech @36 0x00000006 ub4 blocks_ech @40 0x00000030 ub4 offset_ech @44 0x00000a9c ub4 ext_ech @48 0x00000005 ub4 blk_ech @52 0x00000008 ub4 extsize_ech @56 0x00000008 ub4 hw_ech @60 0x014000b8 ub4 hwmapblk_ech @64 0x00000000 ub4 hwoffset_ech @68 0x00000005 ub4 hwblocksshf_ech @72 0x00000000 ub4 hwblksbelow_ech @76 0x0000002b ub4 lhwmext_ech @92 0x00000005 ub4 lhwmblk_ech @96 0x00000008 ub4 lhwmextsize_ech @100 0x00000008 ub4 lhwm_ech @104 0x014000b8 ub4 lhwmapblk_ech @108 0x00000000 ub4 lhwoffset_ech @112 0x00000005 ub4 lhwblocksshf_ech @116 0x00000000 ub4 lhwblksbelow_ech @120 0x0000002b ub4 segtype_ech @208 0x00000001 ub4 blksz_ech @212 0x00002000 ub4 fbsz_echo @216 0x00000000 ub4 l2asoffset_ech @220 0x00001434 ub4 firstbmb3_echo @224 0x00000000 ub4 l2hfinsert_ech @228 0x01400089 ub4 nl2_echo @232 0x00000001 ub4 lastBMB1_echo @236 0x014000a8 ub4 lastBMB2_echo @240 0x01400089 ub4 lastBMB3_echo @244 0x00000000 ub4 mhnext_echo @260 0x00000000 ub4 mhext_echo @264 0x00000006 ub4 mhobj_ech @272 0x00015847 ub4 mhflag_ech @276 0x10000000 struct em(Extent Map) @280 ub4 dba_em[0] @280 0x01400088 ub4 len_em[0] @284 0x00000008 ub4 dba_em[1] @288 0x01400080 ub4 len_em[1] @292 0x00000008 ub4 dba_em[2] @296 0x01400098 ub4 len_em[2] @300 0x00000008 ub4 dba_em[3] @304 0x014000a0 ub4 len_em[3] @308 0x00000008 ub4 dba_em[4] @312 0x014000a8 ub4 len_em[4] @316 0x00000008 ub4 dba_em[5] @320 0x014000b0 ub4 len_em[5] @324 0x00000008 struct am(Auxillary Map) @2736 ub4 fdba_am[0] @2736 0x01400088 ub4 datadba_am[0] @2740 0x0140008b ub4 fdba_am[1] @2744 0x01400088 ub4 datadba_am[1] @2748 0x01400080 ub4 fdba_am[2] @2752 0x01400098 ub4 datadba_am[2] @2756 0x01400099 ub4 fdba_am[3] @2760 0x01400098 ub4 datadba_am[3] @2764 0x014000a0 ub4 fdba_am[4] @2768 0x014000a8 ub4 datadba_am[4] @2772 0x014000a9 ub4 fdba_am[5] @2776 0x014000a8 ub4 datadba_am[5] @2780 0x014000b0 ub4 slbbdba1_am @5192 0x01400089 ub4 tail_kcbh @8188 0x08bc2303 XDUL> ``` ### 5. 格式化解析L2 BMB ```sql XDUL>bmb input fno: 5 input blk: 137 struct kcbh, 20 bytes @0 ub1 type_kcbh @0 0x21 ub1 frmt_kcbh @1 0xa2 ub1 spare1_kcbh @2 0x00 ub1 spare2_kcbh @3 0x00 ub4 rdba_kcbh @4 0x01400089 ub4 bas_kcbh @8 0x002508ba ub2 wrp_kcbh @12 0x0000 ub1 seq_kcbh @14 0x02 ub1 flg_kcbh @15 0x04 ub2 chkval_kcbh @16 0xdebc ub2 spare3_kcbh @18 0x0000 struct hc(Header Control) @76 ub4 pdba_hc @76 0x0140008a ub4 number_hc @80 0x00000003 ub4 nfree_hc @84 0x00000001 ub4 ffree_hc @88 0x00000002 ub4 inc_hc @92 0x00000000 ub4 opcode_hc @96 0x00000000 ub4 objd_hc @104 0x00015847 struct bmb1array @116 ub4 dba_bmb1array[0] @116 0x01400088 ub4 free_bmb1array[0] @120 0x0001 ub4 inst_bmb1array[0] @122 0x0001 ub4 dba_bmb1array[1] @124 0x01400098 ub4 free_bmb1array[1] @128 0x0001 ub4 inst_bmb1array[1] @130 0x0001 ub4 dba_bmb1array[2] @132 0x014000a8 ub4 free_bmb1array[2] @136 0x0005 ub4 inst_bmb1array[2] @138 0x0001 ub4 tail_kcbh @8188 0x08ba2102 XDUL>XDUL> XDUL> ``` ### 6. 格式化解析L1 BMB ```sql XDUL> XDUL>bmb input fno: 5 input blk: 136 struct kcbh, 20 bytes @0 ub1 type_kcbh @0 0x20 ub1 frmt_kcbh @1 0xa2 ub1 spare1_kcbh @2 0x00 ub1 spare2_kcbh @3 0x00 ub4 rdba_kcbh @4 0x01400088 ub4 bas_kcbh @8 0x0024daa8 ub2 wrp_kcbh @12 0x0000 ub1 seq_kcbh @14 0x02 ub1 flg_kcbh @15 0x04 ub2 chkval_kcbh @16 0xad46 ub2 spare3_kcbh @18 0x0000 struct hcbmb1(Header Control) @76 ub4 nbits_bmb1 @76 0x00000004 ub4 embo_bmb1 @80 0xffffffff ub4 fub_bmb1 @88 0x00000003 ub4 total_bmb1 @92 0x00000010 ub2 nranges_bmb1 @96 0x0002 ub2 ownerins_bmb1 @98 0x0001 ub4 nf1_bmb1 @100 0x00000000 ub4 nf2_bmb1 @104 0x00000000 ub4 nf3_bmb1 @108 0x00000000 ub4 nf4_bmb1 @112 0x00000000 ub4 ffd_bmb1 @116 0x00000010 ub4 insowncha_bmb1 @120 0x5e875a85 ub4 lastsucsea_bmb1 @124 0x5e875a85 ub4 pdba_bmb1 @144 0x01400089 ub4 objd_bmb1 @192 0x00015847 ub4 deascnbas_bmb1 @196 0x00247325 ub2 deascnwap_bmb1 @200 0x0000 struct dbarange @116 ub4 dba_dbarange[0] @116 0x01400088 ub4 len_dbarange[0] @120 0x00000008 ub4 offset_dbarange[0] @124 0x00000000 ub4 dba_dbarange[1] @128 0x01400080 ub4 len_dbarange[1] @132 0x00000008 ub4 offset_dbarange[1] @136 0x00000008 ub4 tail_kcbh @8188 0xdaa82002 XDUL> ``` ### 7. Segment Header Block Types ``` Decimal Hex Type 1 0x01 undo segment header 11 0x0b data file header 12 0x0c data segment header with FLG blocks 14 0x0e unlimited undo segment header 15 0x0f unlimited save undo segment header 16 0x10 unlimited data segment header 17 0x11 unlimited data segment header with FLG blocks 18 0x12 extent map block 23 0x17 bitmapped segment header 29 0x1d bitmapped file space header 32 0x20 first level bitmap block 33 0x21 second level bitmap block 34 0x22 third level bitmap block 35 0x23 Pagetable segment header block 36 0x24 Pagetable extent map block 37 0x25 System Managed Undo Extent Map Block ``` ### 8. dump 段头块 ```sql alter session set tracefile_identifier='orastar_01'; oradebug setmypid alter system dump datafile 5 block 138; oradebug close_trace oradebug tracefile_name --dump Extent Map结果： Extent Map ----------------------------------------------------------------- 0x01400088 length: 8 0x01400080 length: 8 0x01400098 length: 8 0x014000a0 length: 8 0x014000a8 length: 8 0x014000b0 length: 8 --手工解析 Extent Map结果： struct em(Extent Map) @280 ub4 dba_em[0] @280 0x01400088 ub4 len_em[0] @284 0x00000008 ub4 dba_em[1] @288 0x01400080 ub4 len_em[1] @292 0x00000008 ub4 dba_em[2] @296 0x01400098 ub4 len_em[2] @300 0x00000008 ub4 dba_em[3] @304 0x014000a0 ub4 len_em[3] @308 0x00000008 ub4 dba_em[4] @312 0x014000a8 ub4 len_em[4] @316 0x00000008 ub4 dba_em[5] @320 0x014000b0 ub4 len_em[5] @324 0x00000008 通过对比Oracle dump结果与手工解析Extent Map结果一致。 ```