Error 2543

Severity Level 16

Message Text

Table Corrupt: Extent structures are linked incorrectly; check the following extent: alloc pg#=%ld extent#=%ld previous extent# on this extent=%ld previous extent should be=%ld

Explanation

DBCC CHECKALLOC detected a break in the chain of allocation structures (extents) for a particular object. SQL Server references an object's extents only when allocating or deallocating space for that object, so this error does not affect queries against the data. However, any operations that require allocating or deallocating space might fail at run time.

Action

Follow these steps:

1. Note the first extent# in the message text. To find the object ID and the index ID of the object that has the error, see "Associating a Page with an Object" in Chapter 24, "Additional Problem-solving Techniques."
2. If the object ID is less than or equal to 100, the error is on a system table. Restore the database from a known clean backup.

   If the object ID is greater than 100, the error is on a user table.

   • If this error occurs on table data (the index ID = 0), restore the database from a known clean backup.
   • If this error occurs on an index, you can usually clear 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.