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Home -> Community -> Mailing Lists -> Oracle-L -> Re: DBMS_REPAIR package usage
Yong,
Thanks a lot for all the research! :D
The file# that actaully contains this block is 9. My database is not that big at all.
I did do some research myself and some Oracle analysts in the World Wide Support does suggest that the influxed blocks are very likely to be a fractured block. But I reallly have no idea how it got in there... .
Winnie
yong huang <yong321_at_yahoo.com> on 03/23/2001 04:01:21 PM
To: oracle-l_at_fatcity.com
cc: Winnie_Liu_at_infonet.com, yong321_at_yahoo.com, jeremiah_at_wolfenet.com
Hi, Winnie,
Just a little more research. I wonder how you can have an rdba that big, 0x24070020, which is 604438560 in decimal.
SQL> var a number;
SQL> exec :a := dbms_utility.data_block_address_file(604438560);
PL/SQL procedure successfully completed.
SQL> print
A
144
SQL> exec :a := dbms_utility.data_block_address_block(604438560);
PL/SQL procedure successfully completed.
SQL> print
A
458784
This is done on 8.1.6. It says the block is in file 144, block 458784. Why
does
your error say file=0? Anyway, in case you do have a file numbered 144,
check
to see if there's an object there. If it's indeed file 0, the dba should be
the
same as block#, 458784, or 0x70020. DBMS_UTILITY.MAKE_DATA_BLOCK_ADDRESS
can
confirm this. However, that file# 0 may be just an indicator that that
information is lost, as multiple other 0's look like.
I believe dbv reports an error when it encounters a fractured block, i.e.,
the
first two bytes of tail (0003 in your case) does not match the last two
bytes
of rdba (0020). We know how a fractured block is created during hot backup.
But
I don't understand why an offlined datafile (as you said in another email)
can
contain fractured blocks. Maybe Jeremiah Wilton can give a better answer.
Yong Huang
yong321_at_yahoo.com
you wrote:
I have a datafile in my production box (a user data tablespace), when I run dbv against it, it showed that 5 blocks are "influxed"
Page 458784 is influx - most likely media corrupt
***
Corrupt block relative dba: 0x24070020 file=0. blocknum=458784.
Fractured block found during dbv:
Data in bad block - type:0. format:0. rdba:0x00000000
last change scn:0x0000.00000000 seq:0x0 flg:0x00
consistancy value in tail 0x0003c204
check value in block header: 0x0, check value not calculated
spare1:0x0, spare2:0x0, spare2:0x0
We can copy this file to tape, dd this file. On the OS disk level, the OS
does
n
ot treat this as corrupted. But it is corrupted on the oracle
(software) level.
I've checked and can't find any object associate with these 5 corrupted blcok.
That means that there is no data inside those blocks.
Since the tablespace is about 12 GB on a highly active system (which only
got 3
hours maintance window each month), export/import (then drop the
tablespace)
which Oracle support suggested is mostly out of the question. (Especially,
it
is
very hard for me to convince the sysadmin that the blocks are
corrupted
as they don't see any I/O error associate with this file and the developers
don'
t see any problem with the application either!)
I am currently thinking about upgrading this database to 8.1.6 to make use
of
th
e DBMS_REPAIR package to make those blocks as "unusable". But I
am not sure that if the DBMS_REPAIR package can run against the blocks
which do
not belong to any objects!! Can someone give me some
guidences?
thanks
Winnie
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