|Message:||Attempt to fetch logical page %S_PGID in database %d failed. It belongs to allocation unit %I64d not to %I64d.|
This error generally signifies page or allocation corruption in the specified database. SQL Server detects corruption when reading pages belonging to a table either by following the page linkages or by using the Index Allocation Map (IAM). All pages allocated to a table must belong to one of the allocation units associated with the table. If the allocation unit ID contained in the page header does not match an allocation unit ID associated with the table, this exception is raised. The first allocation unit ID listed in the error message is the ID present in the page header, the second allocation unit value is the ID associated with the table.
Data Corruption Errors
A severity level of 21 indicates potential data corruption. Possible causes are a damaged page chain, a corrupt IAM, or an invalid entry in the sys.objects catalog view for that object. These errors are often caused by hardware or disk device driver failure.
A severity level of 12 indicates a potential transient error; that is, it occurs in the cache and does not indicate damage to data on disk. Transient 605 errors can be caused by the following conditions:
In general, if the error occurs during data access but subsequent DBCC CHECKDB operations complete without error, the 605 error was probably transient.