does dbcc check also repair with only

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does dbcc check also repair with only

nexxexium

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December 9, 2009 at 5:22 am

#207047

Does the following statement also repair found errors and/or minor issues or does this statement repair nothing but only show information on existing errors?
DBCC CHECKDB ('databasename') with physical_only

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Gail Shaw SSC Guru Points: 1004504 More actions · Answer 1

CheckDB does not repair unless a repair level is specified.

Please note, repair should never be the first thing considered for a corruption problem. In many cases it's the last resort. If you have corruption, post the errors here (from a full checkDB not one with physical only) and someone will advise you on what to do.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

steveb. SSC-Forever Points: 46733 More actions · Answer 2

This will not repair anything, it simply scans the database for physical structure errors and is a lot quicker to run that a full scan does a lot more logical checks.

To repair you need to use a REPAIR option with the appropriate type of repair REPAIR_ALLOW_DATA_LOSS | REPAIR_FAST | REPAIR_REBUILD

You need to aware of the potential data loss of repairing, restoring from a good-backup is preferable.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 3

steveb. (12/9/2009)
This will not repair anything, it simply scans the database for physical structure errors and is a lot quicker to run that a full scan does a lot more logical checks.

However it will only detect physical corruptions. There are a lot of potential corruptions that a physical only check will not pick up.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

Paul Randal One Orange Chip Points: 29544 More actions · Answer 4

On 2000 it will actually fix up incorrect PFS page free space bits silently, even if you don't say to do repairs. There was a bug in the algorithm that maintains them (in the main Storage Engine, not in CHECKDB) so it was deemed easier to just repair them than fix the bug - it was fixed in 2005.

Apart from that, it won't do any repairs.

Paul Randal
CEO, SQLskills.com: Check out SQLskills online training!
Blog:www.SQLskills.com/blogs/paul Twitter: @PaulRandal
SQL MVP, Microsoft RD, Contributing Editor of TechNet Magazine
Author of DBCC CHECKDB/repair (and other Storage Engine) code of SQL Server 2005