I've seen similar looking corruptions on a few of my databases as
well. I never did get to the bottom of the problem. However, in
terms of solving the problem and moving on, you ought to be able to
set MAXCORRUPT greater than then number of corrupt blocks you have,
backup the datafile(s) affected, and then, restore datafile(s) from
backup. Since they were corrupt on backup, Oracle will format the
block at restore time. As long as the block is not part of any
segment, that's ok. Note that if any corrupted block is part of any
segment, the above is a bad idea.
-Mark
*--*
*Mark J. Bobak*
*Senior Oracle Architect*
*P**ro**Q**uest Information & Learning*
There is nothing so useless as doing efficiently that which shouldn’t
be done at all. –Peter F. Drucker, 1909-2005
------------------------------------------------------------------------
*From:* oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of
*Uldis.Pavuls@xxxxxxxxxxxxxxx
*Sent:* Wednesday, January 03, 2007 12:35 PM
*To:* rshamsud@xxxxxxxxxxxx
*Cc:* oracledba.williams@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
*Subject:* RE: RMAN fails because of corrupt block in seemingly free
space in SYSTEM
Riyai,
it's quite possible the OS partition has been resized, i do not know,
my role is rather consulting at need. I'm not on-site, it makes things
a bit difficult. However, I did not find any tracs of resizing in the
alert-log, at least not for the system tablespace (they certainly had
had some difficulties with undo resizing, however).
In fact there is account for 10 blocks in row corrupted in similar
way, all fractured and with CORRUPTION_CHANGE#=0, rman just falls back
on the first, although, it seems, have recorded other piece of 9
blocks - next to the first one - in v_$database_block_corruption.Citation:
select T.NAME "T-space", D.NAME "Filename", C."FILE#" "FileId",
C."BLOCK#" "BlockId", C.BLOCKS,
C."CORRUPTION_CHANGE#" "Corr.SCN", C.CORRUPTION_TYPE
from SYS."V_$DATABASE_BLOCK_CORRUPTION" C, SYS."V_$DATAFILE" D,
SYS."V_$TABLESPACE" T
where C."FILE#" = D."FILE#" and D."TS#" = T."TS#" order by 1, 2, 3, 4 ;
<Output as CSV>:
SYSTEM;/dev/rcmssystem;1;65535;1;0;FRACTURED
SYSTEM;/dev/rcmssystem;1;65536;9;0;FRACTURED
<end of output>
All datafiles are locally managed and on raw devices (under VLM on AIX
5.3, so they are partitions in fact); there should be my first post
(2 January, 2007) with a bit more info.
Thanks for the idea of use of transportable tablespaces, it didn't
occur to me. I'll certainly consider that. I was rather thinking about
shrinking that file and then re-expanding it, that should clear the
corruption on success - how do you think? It would be faster if
succeeded. Altogether on the second thought CORRUPTION_CHANGE#=0
should mean media corruption, so your approach may be safer in long run.
Best regards,
Uldis
Uldis Pavuls
DBA, TietoEnator
41 Lacplesa Str., Riga, Latvia, LV 1011
phone +371 7 286 660, fax +371 7 771 313
mailto:Uldis.Pavuls@xxxxxxxxxxxxxxx
http://www.tietoenator.com <http://www.tietoenator.com/>
-----Original Message-----
*From:* oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Riyaj Shamsudeen
*Sent:* otrdiena, 2007. gada 2. janvārī 23:50
*To:* Pavuls Uldis
*Cc:* oracledba.williams@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
*Subject:* Re: RMAN fails because of corrupt block in seemingly
free space in SYSTEM
Uldis
rman does not backup "never used" blocks, not "free" blocks.
It is quite possible that this block was previously used and rman
will back this block also.
Looking at the following lines, clearly even rdba in the block
is corrupted. Many other fields are corrupted too. Weird thing is
that block is corrupted exactly at 65535 block, which happened to
be a binary power of 16. Was this raw device extended using OS
tools in the past ? If yes, from what size ? What is your
db_block_size ?
***
Corrupt block relative dba: 0x0040ffff (file 1, block 65535)
Fractured block found during backing up datafile
Data in bad block -
type: 0 format: 2 rdba: 0x0000ffff
last change scn: 0x0000.00000000 seq: 0x1 flg: 0x05
consistency value in tail: 0x0074117a
check value in block header: 0xfef9, computed block checksum: 0x9
spare1: 0x0, spare2: 0x0, spare3: 0x0
***
Can you dump the block itself and print trace lines ? alter
system dump datafile 1 block min 65535 block max 65535
Also, in your SQL, can you select block_id too ?
select TABLESPACE_NAME,FILE_ID,BLOCKS, BLOCK_ID
from SYS.DBA_FREE_SPACE where FILE_ID=1
and BLOCK_ID <=65535 and (BLOCK_ID+BLOCKS-1)>=65535;
Is system locally managed or dictionary managed, in your
database ?
I am not sure why Oracle support would say that it is okay to
have corrupt block, that too in a system tablespace. If I were
you, I would be looking at creating a new database and
transporting non-system tablespaces from current database to new
database, urgently.
Thanks
Riyaj Shamsudeen
