Block Corruption in empty pages in Oracle 11g
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From: zigzagdna on 5 Aug 2010 13:03 On Aug 5, 7:54 am, Mladen Gogala <gogala.mla...(a)gmail.com> wrote: > On Wed, 04 Aug 2010 20:08:15 -0700, zigzagdna wrote: > > Another strange thing I noticed: > > 1. When doing export backup, export backup reports about corrupted > > blocks. > > Export is not a backup. > > > 2. When I do expdp no errors are reported. So question is why is exp > > command checking empty blocks? > > 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 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.
From: joel garry on 5 Aug 2010 13:19 On Aug 5, 4:54 am, Mladen Gogala <gogala.mla...(a)gmail.com> wrote: > On Wed, 04 Aug 2010 20:08:15 -0700, zigzagdna wrote: > > Another strange thing I noticed: > > 1. When doing export backup, export backup reports about corrupted > > blocks. > > Export is not a backup. 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/E11882_01/backup.112/e10642/glossary.htm#i997880 > > > 2. When I do expdp no errors are reported. So question is why is exp > > command checking empty blocks? > > 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. > 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/E11882_01/server.112/e10595/schema003.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/E11882_01/server..112/e10701/original_export.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/2010/aug/04/garage-doors-glitching-once-again/
From: Steve Howard on 5 Aug 2010 21:51 On Aug 5, 12:59 pm, zigzagdna <zigzag...(a)yahoo.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. You don't have to assume, just dump the block reported by RMAN as being corrupt.
From: zigzagdna on 6 Aug 2010 19:22 On Aug 5, 9:51 pm, Steve Howard <stevedhow...(a)gmail.com> wrote: > On Aug 5, 12:59 pm, zigzagdna <zigzag...(a)yahoo.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. > > You don't have to assume, just dump the block reported by RMAN as > being corrupt. Soory, don't undestand why do you mean by dump the block.
From: John Hurley on 6 Aug 2010 19:51
zigzag: # Soory, don't undestand why do you mean by dump the block. Try searching with something like google ... Use words like these "oracle how to dump a data block" ... |