I am using Oracle 11.1.0.7.1 on HP UNIX 11i.
On several occasions, I have been seen that block corruptions are
reported by rman. I have never seen this problem in previous release
of databases; but I have seen it more than once in Oracle 11g.
However, when I run dbv command; I do not see any corruption in data
and index blocks; so my conclusion is block corruption is in empty
pages.
Anyone has ideas why block corruption occurs in Oracle 11g. Has
Oracle’s algorithm for checking block corruption have changed in 11g;
I.e.; these corruptions existed in older Oracle releases but not
reported by rman,

Another strange thing I noticed:
1. When doing export backup, export backup reports about corrupted
blocks.
2. When I do expdp no errors are reported.
So question is why is exp command checking empty blocks?


Any insights in above will be appreciated.

On Wed, 04 Aug 2010 20:08:15 -0700, zigzagdna wrote:

Export is not a backup.

Because it's doing full table scans. Full table scan stops at HWM, not
before. Also, exp utility is deprecated in 11.2. Do not use it.





--
http://mgogala.byethost5.com

On Aug 4, 11:08*pm, zigzagdna <zigzag... (AT) yahoo (DOT) com> wrote:
If the rman backup and expdp are identifying corrupted blocks what
does the following query show?

set echo off
--
-- Display corrupt block information
--
-- 20100105 Mark D Powell Save 4 future use
--
select
*
from
v$database_block_corruption
order by
file#
,block#
/

You can find the object idenfified by this query by looking at
dba_extents for the extent that the identified files and blocks are
held within.

HTH -- Mark D Powell --

zigzag:

I have not seen anything similar in 11.1.0.7 ...

My experience with any block corruption issues has always been storage
related or from unexpected system failures ... in other words shaky
hardware in one form or another.

Any reason you are not patched up to 11.1.0.7.4 ? I have seen some
hpux specific things in the bug lists but not looked closely since we
do not run any databases on hpux any longer.

On Aug 5, 8:18*am, Mark D Powell <Mark.Powe... (AT) hp (DOT) com> wrote:
Yes, tis query shows some block corruptions but it does not tell you
corrupted blocks are empty. When I run dbv
it does not show any corruption in data or indexes. So I am assuming
that corruption is in empty pages.

On Aug 5, 7:54*am, Mladen Gogala <gogala.mla... (AT) gmail (DOT) com> wrote:
exp has been deprecatd in 11g; but expdp is way too slow in 11.1.0.7.
I have not used it in 11.2 so not sure slowness
problems got fixed. It takes me 3 hours to do a ful export; but 10
hours to do expdp. Most of time expdp seems
to be waiting doing data dictionary backup or so. Severl people have
reported slowness problem. expdp has lots of nice features but its
slowness as well as some bugs at least in 11.1 make me not use it in
production.

On Aug 5, 4:54*am, Mladen Gogala <gogala.mla... (AT) gmail (DOT) com> wrote:
It is a logical backup. Says so right there in the docs. It has its
uses, transactional recovery is not one of them.
http://download.oracle.com/docs/cd/E...ry.htm#i997880

Which high water mark? Blocks up to the low high watermark are
formatted, from there to the high high watermark they are not. This
situation can occur if you use the compact option of shrink space, and
can be fixed by doing a shrink without the compact option.
http://download.oracle.com/docs/cd/E...htm#ADMIN12625

There are a couple of exceptions to the deprecation. I like the 10g
typo in the exceptions: http://download.oracle.com/docs/cd/E....htm#SUTIL3634

Of course, I don't have 11g, so this is all academic to me. I could
just be making embarrassing noises.

jg
--
@home.com is bogus.
(I used to work for a manufacturer that was noted for being the first
to make garage door openers that work in the San Diego area)
http://www.signonsandiego.com/news/2...ng-once-again/

On Aug 5, 12:59*pm, zigzagdna <zigzag... (AT) yahoo (DOT) com> wrote:
You don't have to assume, just dump the block reported by RMAN as
being corrupt.

On Aug 5, 9:51*pm, Steve Howard <stevedhow... (AT) gmail (DOT) com> wrote:
Soory, don't undestand why do you mean by dump the block.

zigzagdna wrote:
http://tinyurl.com/38jsprs

--
Jeroen