Checking for datafile corruption

[blakmk]

Does anyone know how to check for datafile corruption on oracle 7.3.4. Ive basically just moved a 60Gb of data and I want to check if any of it got corrupted along the way.

[kiewer]

Just run $ORACLE_HOME/bin/dbv against each datafile.

[blakmk]

Can the database be open when I run this?

[kiewer]

yes, this is supported.

[Sharma]

Sometime dbverify may give false alarm about corruption. Other alternative is to run export on the tablespace containing the datafile. You can create dump in /dev/null so that actual export file will not be occupying any space, but if corruption is tehre it will errorout.

[slimdave]

The export method wouldn't identify corruption in an index segment, would it?

[stecal]

LIMITATIONS -----------
1. Export only reads:
- user data below the high water mark;
- parts of the data dictionary, while looking up information concerning the objects being exported.

2. Export does not detect all corruptions:
- does not detect disk corruptions above the high water mark;
- does not detect corruptions in indexes, or in free or temporary extents;
- does not detect all corruptions in the data dictionary (the export utility does not read all of the data dictionary, so there could still be undetected corruptions in the SYSTEM tablespace).

[Sharma]

Problem with DBVerify, it will check the corruption datafile on all the ever used blocks. So, if you have corruption in a table in the past and you dropped the table, DBVerfiy may go and give you the corruption in the table which doesn't exists or the blocks which are not occupied by any objects.

I think DBVerify will not check corruption in disk (hardware corruption), will it?

I would use, run dbverify, if it gives corruption then run export as it will read all the records from the object.

[julian]

Originally posted by blakmk
Does anyone know how to check for datafile corruption on oracle 7.3.4. Ive basically just moved a 60Gb of data and I want to check if any of it got corrupted along the way.

I recommend Note:77587.1.