Error 2544

Severity Level 16

Message Text

Table Corrupt: Extent id %Id on allocation pg# %Id had object id %Id (object name = %.*s) on but used bit off

Explanation

This error occurs when DBCC CHECKALLOC has found an extent with object information in the structure, even though the extent has been marked as unused. Space is allocated to objects in a database based on the extent structure, which contains 8 2K pages. An extent structure manages each of these 2K pages, indicating whether they are used by the object referenced in the extent structure. When all the pages are not being used, the extent is deallocated, which results in the removal of any references to an object in the database and the extent itself being marked as unused.

Note Occasionally, DBCC CHECKALLOC reports this error when no real error condition exists. Run DBCC CHECKALLOC in single-user mode if you suspect the 2544 error is incorrect.

Action

Follow these steps:

1. Examine the index ID associated with the page number indicated by the extent# in the message to determine whether the error occurred on a table data or on an index. For information about the object ID and the index ID of the object that has the error, see Chapter 24, "Additional Problem-solving Techniques."
2. Restore the database:
   • If the object ID is less than or equal to 100, the error is on a system table. Restore the database from a clean backup.
   • If the object ID is greater than 100, the error is on a user table.
   • If this error occurs on a table (the index ID = 0), restore the database from a clean backup.
   • If this error occurs on an index, you can usually correct it by dropping and re-creating the index. If dropping and re-creating the index is not feasible, or if you cannot drop the index, contact your primary support provider for assistance.

If the problem persists, contact your primary support provider. Have the output from the appropriate DBCC statements available for review.