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Different data-structures in Oracle Database [message #317573] Fri, 02 May 2008 00:51 Go to next message
kiran.satyan
Messages: 25
Registered: March 2008
Location: Bangalore
Junior Member
Hi All,

What are all the data-structures which creates the database objects like tables,clusters and all..

Just like Indexes are B-Tree,Bitmap.

When we create a table what kind of datastructure it is making in the background(harddisc)..?

How oracle understands the data is stored in row-column format..??

.dbf
.log
.ctl
.trc
Whether all these files contain the same kind of datastrauctures?

Thanks & Regards

Kiran S

Re: Different data-structures in Oracle Database [message #317582 is a reply to message #317573] Fri, 02 May 2008 01:49 Go to previous messageGo to next message
Michel Cadot
Messages: 64103
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
Quote:
Whether all these files contain the same kind of datastrauctures?

No.

Structure is something Oracle internal, it changes at (almost) each major version (and sometimes even at minor version).
There is no documentation on it.
If you want to see an interpretation of what's inside the block, you can use "alter system dump" command.

Regards
Michel
Re: Different data-structures in Oracle Database [message #317638 is a reply to message #317582] Fri, 02 May 2008 04:55 Go to previous messageGo to next message
kiran.satyan
Messages: 25
Registered: March 2008
Location: Bangalore
Junior Member
Dear Michel,

I've tried it like this

"alter system dump datafile 5 block min 50 block max 55;"

My database has given this result

-----------------------------------------------------------
/home/oracle/admin/b2k/udump/b2k_ora_10848.trc
Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.4.0 - Production
ORACLE_HOME = /home/oracle/product/9.2.0
System name: Linux
Node name: vb007
Release: 2.4.21-4.EL
Version: #1 Fri Oct 3 18:13:58 EDT 2003
Machine: i686
Instance name: b2k
Redo thread mounted by this instance: 1
Oracle process number: 24
Unix process pid: 10848, image: oracle@vb007 (TNS V1-V3)

*** 2008-05-02 15:05:03.967
*** SESSION ID:(27.169) 2008-05-02 15:05:03.948
Start dump data blocks tsn: 5 file#: 5 minblk 50 maxblk 55
buffer tsn: 5 rdba: 0x01400032 (5/50)
scn: 0x0000.004765de seq: 0x02 flg: 0x04 tail: 0x65de2102
frmt: 0x02 chkval: 0x2612 type: 0x21=SECOND LEVEL BITMAP BLOCK
Dump of Second Level Bitmap Block
number: 1 nfree: 1 ffree: 0 pdba: 0x01400033
opcode:0
xid:
L1 Ranges :
--------------------------------------------------------
0x01400031 Free: 5 Inst: 1

--------------------------------------------------------
buffer tsn: 5 rdba: 0x01400033 (5/51)
scn: 0x0000.004765de seq: 0x03 flg: 0x04 tail: 0x65de2303
frmt: 0x02 chkval: 0x79a3 type: 0x23=PAGETABLE SEGMENT HEADER
Extent Control Header
-----------------------------------------------------------------
Extent Header:: spare1: 0 spare2: 0 #extents: 1 #blocks: 8
last map 0x00000000 #maps: 0 offset: 2716
Highwater:: 0x01400034 ext#: 0 blk#: 3 ext size: 8
#blocks in seg. hdr's freelists: 0
#blocks below: 0
mapblk 0x00000000 offset: 0
Unlocked
--------------------------------------------------------
Low HighWater Mark :
Highwater:: 0x01400034 ext#: 0 blk#: 3 ext size: 8
#blocks in seg. hdr's freelists: 0
#blocks below: 0
mapblk 0x00000000 offset: 0
Level 1 BMB for High HWM block: 0x01400031
Level 1 BMB for Low HWM block: 0x01400031
--------------------------------------------------------
Segment Type: 1 nl2: 1 blksz: 8192 fbsz: 0
L2 Array start offset: 0x00001434
First Level 3 BMB: 0x00000000
L2 Hint for inserts: 0x01400032
Last Level 1 BMB: 0x01400031
Last Level II BMB: 0x01400032
Last Level III BMB: 0x00000000
Map Header:: next 0x00000000 #extents: 1 obj#: 82538 flag: 0x20000000
Extent Map
-----------------------------------------------------------------
0x01400031 length: 8

Auxillary Map
--------------------------------------------------------
Extent 0 : L1 dba: 0x01400031 Data dba: 0x01400034
--------------------------------------------------------

Second Level Bitmap block DBAs
--------------------------------------------------------
DBA 1: 0x01400032

buffer tsn: 5 rdba: 0x00000034 (0/52)
scn: 0x0000.00000000 seq: 0x01 flg: 0x05 tail: 0x00000001
frmt: 0x02 chkval: 0x0734 type: 0x00=unknown
Hex dump of corrupt header 4 = CORRUPT
Dump of memory from 0x0AD7CC00 to 0x0AD7CC14
AD7CC00 00000200 00000034 00000000 05010000 [....4...........]
AD7CC10 00000734 [4...]
buffer tsn: 5 rdba: 0x00000035 (0/53)
scn: 0x0000.00000000 seq: 0x01 flg: 0x05 tail: 0x00000001
frmt: 0x02 chkval: 0x0735 type: 0x00=unknown
Hex dump of corrupt header 4 = CORRUPT
Dump of memory from 0x0AD7CC00 to 0x0AD7CC14
AD7CC00 00000200 00000035 00000000 05010000 [....5...........]
AD7CC10 00000735 [5...]
buffer tsn: 5 rdba: 0x00000036 (0/54)
scn: 0x0000.00000000 seq: 0x01 flg: 0x05 tail: 0x00000001
frmt: 0x02 chkval: 0x0736 type: 0x00=unknown
Hex dump of corrupt header 4 = CORRUPT
Dump of memory from 0x0AD7CC00 to 0x0AD7CC14
AD7CC00 00000200 00000036 00000000 05010000 [....6...........]
AD7CC10 00000736 [6...]
buffer tsn: 5 rdba: 0x00000037 (0/55)
scn: 0x0000.00000000 seq: 0x01 flg: 0x05 tail: 0x00000001
frmt: 0x02 chkval: 0x0737 type: 0x00=unknown
Hex dump of corrupt header 4 = CORRUPT
Dump of memory from 0x0AD7CC00 to 0x0AD7CC14
AD7CC00 00000200 00000037 00000000 05010000 [....7...........]
AD7CC10 00000737 [7...]
End dump data blocks tsn: 5 file#: 5 minblk 50 maxblk 55
-----------------------------------------------------------------

But i cant find any information about the datastrauctures in these 5 blocks..!

How do you interpret this trace file.?

Thanks & Regards

Kiran

Re: Different data-structures in Oracle Database [message #317647 is a reply to message #317638] Fri, 02 May 2008 05:07 Go to previous messageGo to next message
Michel Cadot
Messages: 64103
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
These express the structure of the blocks.
How to interpret this in out of the scope of a forum and can be the subject of a book with several hundred of pages.

Regards
Michel
Re: Different data-structures in Oracle Database [message #317822 is a reply to message #317573] Sat, 03 May 2008 22:32 Go to previous message
TheSingerman
Messages: 49
Registered: April 2008
Location: Brighton, Michigan
Member
Search for Steve Adams and Richard Foote, they both have done this kind of analysis. Also, the book Tales of the Oak Table has a couple of chapters where this is done.
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