Data block dump and RDBA conversion

Data | conversion
Data block dump and RDBA conversion

Original link:

Http://www.eygle.com/internal/How_to_dump_datablock.htm

Tuesday, 2004-08-31 17:51 eygle


Many times we need to dump Oracle's data blocks to study its content, and Oracle provides a good way to do this, and we'll explain it in the following example:






[Oracle@jumper udump]$ Sqlplus "/As SYSDBA" Sql*plus:release 9.2.0.3.0-production on Tue Aug to 17:01:27 2004Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved. Connected to:oracle9i Enterprise Edition release 9.2.0.3.0-productionwith The partitioning, OLAP and Oracle Data Mining Optionsjserver release 9.2.0.3.0-productionsql> select Rowid,deptno,dname,loc from Scott.dept; ROWID DEPTNO dname LOC-------------------------------------------------------aaadz7aabaaagk6aaa ACCOUNTING NEW Yorkaaadz7aabaaagk6aab dallasaaadz7aabaaagk6aac SALES Chicagoaaadz7aabaaagk6aad OPERATIONS bostonsql& Gt Select File_id,block_id,blocks from dba_extents where segment_name= ' DEPT '; file_id block_id BLOCKS------------------------------1 25273 8sql> alter system dump DATAFILE 1 Block min 25273 bloc K Max 25274; System altered. Sql>! [Oracle@jumper udump]$ ls-ltotal 4-rw-r-----1 Oracle DBA 3142 Aug to 17:04 hsjf_ora_13674.trc[oracle@jumper udump]$ more Hsjf_Ora_13674.trc/opt/oracle/admin/hsjf/udump/hsjf_ora_13674.trcoracle9i Enterprise Edition Release 9.2.0.3.0- Productionwith the partitioning, OLAP and Oracle Data Mining optionsjserver Release 9.2.0.3.0-productionoracle_home =/O Pt/oracle/product/9.2.0system name:linuxnode name:jumper.hurray.com.cnrelease:2.4.18-14version: #1 Wed Sep 4 13:35:50 EDT 2002machine:i686instance Name:hsjfredo thread mounted by this instance:1oracle process Number:9unix process pid:1 3674, image:oracle@jumper.hurray.com.cn (TNS v1-v3) * * * 2004-08-31 17:04:27.820*** session ID: (8.3523) 2004-08-31 17:04:27.819start dump data blocks tsn:0 file#: 1 minblk 25273 maxblk 25274buffer tsn:0 rdba:0x004062b9 (1/25273) scn:0 x0000.0057c70d seq:0x01 flg:0x04 tail:0xc70d1001frmt:0x02 chkval:0x12e3 type:0x10=data SEGMENT header-unlimited Ex Tent Control Header-----------------------------------------------------------------Extent header:: spare1:0 spare2 : 0 #extents: 1 #blocks: 7 last map 0x00000000 #maps:0 offset:4128 highwater:: 0X004062BB ext#: 0 blk#: 1 ext size:7 #blocks in seg. HDR ' s freelists:1 #blocks below:1 mapblk 0x00000000 offset:0 unlocked Map Header:: Next 0x00000000 #extents: 1 obj#: 13 947 flag:0x40000000 Extent Map-----------------------------------------------------------------0x004062ba length:7 NFL = 1, NFB = 1 Typ = 1 NXF = 0 ccnt = 1 SEG LST:: flg:used lhd:0x004062ba ltl:0x004062ba buffer tsn:0 rdba:0x004062 BA (1/25274) scn:0x0000.0131909b seq:0x07 flg:0x04 tail:0x909b0607frmt:0x02 chkval:0xa8e7 Type:0x06=trans dataBlock Header dump:0x004062ba Object ID on block? Y seg/obj:0x367b csc:0x00.131909a itc:2 flg:o typ:1-DATA fsl:0 fnx:0x0 ver:0x01 Itl Xid Uba Flag Lck scn/fsc0x01 0X0001.02A.000003F3 0x0080000b.0188.08 C---0 scn 0x0000.0057c70e0x02 0x0000.000.00000000 0x00000000.0000.00----0 FSC 0 x0000.00000000 Data_block_dump,data header at 0XADB505C===============TSIZ:0X1FA0HSIZ:0X1APBL:0X0ADB505CBDBA: 0X004062BA 76543210flag=--------Ntab=1nrow=4frre=-1fsbo=0x1afseo=0x1f44avsp=0x1f2atosp=0x1f2a0xe:pti[0] nrow=4 offs=00x12:pri[0] offs= 0X1F860X14:PRI[1] offs=0x1f700x16:pri[2] offs=0x1f5c0x18:pri[3] Offs=0x1f44block_row_dump:tab 0, row 0, @0x1f86tl:26 FB:--h-fl--lb:0x0 cc:3col 0: [2] C1 0bcol 1: [A] 2 4f 4e 4e 47col: [8] 4e (4f) 4btab 0, Row 1, @0x1f70tl:22 fb:--h-fl--lb:0x0 cc:3col 0: [2] C1 15col 1: [8] (48col 2: [6] 44 41 4 C 4c 53tab 0, Row 2, @0x1f5ctl:20 fb:--h-fl--lb:0x0 cc:3col 0: [2] C1 1fcol 1: [5] 4c 53col 2: [7] 43 4ftab 0, Row 3, @0x1f44tl:24 fb:--h-fl--lb:0x0 cc:3col 0: [2] C1 29col 1: [Ten] 4f 50 45 52 41 54 49 4 F 4e 53col 2: [6] 4f 4f 4eend_of_block_dumpend dump data blocks tsn:0 file#: 1 minblk 25273 maxblk 25274


One question that many people often ask is, how is rdba converted?

RDBA:0X004062BA (1/25274)

Let's use this example to introduce.

RDBA has changed from Oracle6->oracle7->oracle8 three times:

In Oracle6, the RDBA is represented by a 6-bit 2-digit number, which means that the data block can only have 2^6=64 data files (remove all 0 and 1, which can actually represent only 62 files)

In Oracle7, the file number in RDBA is increased to 10 bits, and for backward compatibility, 4 bits are taken from the high position of the block number as the high level of the file number. This rowid from 6->7 does not need to be changed.

In Oracle8, the file number is still represented in 10 digits, but no replacement is needed, and the relative file number (rfile#) is introduced for backward compatibility, so there is no need to change from Oracle7 to Oracle8,rowid.

Examples are as follows:


In Oracle6: For example: File 8, block 5,689,226 bit block number ==56892 vv vvvvvvvv vvvvvvvv vvvvvvvv00100000 00000000 11011110 00111100 ^^ ^^ ^^ 6 Bit file number ==8 in Oracle7: For example: File 255, block 56892 11111100 11000000, 11011110 00111100 F c C 0 D E 3 C \_____/\___/\_______________ ________/ | | | | | block = 0xde3c = 56892 \_____________ | V v 0011 111111 = 0xFF = 255-note that the high and low places to be replaced to get the correct file# in Oracle8: for example: File 255, block 56892 11111100 11000000 11011110 001 11100 F c C 0 D E 3 C \_____/\___/\_______________________/| | | block = 0xde3c = 56892 \_____________ | \ v V 0011 1111 0011 = 03F3 = 1011-This is the relative file number



For the example in our test:

RDBA:0X004062BA (1/25274)

which is: 0000 0000 0100 0000 0110 0010 1011 1010

Top 10 for rfile#: 0000 0000 01 = 1

The latter 22 digits are block#:00 0000 0110 0010 1011 1010 = 25274