https://learn.microsoft.com/de-de/previous-versions/sql/sql-server-2008-r2/ms190400(v=sql.105)?redirectedfrom=MSDN
Clustered Index Seek (Showplanoperator) | Microsoft Learn
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https://support.microsoft.com/en-gb/topic/kb957823-fix-the-clustered-index-table-may-take-longer-than-you-expect-to-be-rebuilt-when-you-use-the-alter-index-rebuild-statement-in-sql-server-b9d56f2f-1885-2f12-9b31-e72740d8882b
KB957823 - FIX: The clustered index table may take longer than you expect to be rebuilt when you...
Describes an issue that occurs when the clustered index table contains file stream data in SQL Server 2008, SQL Server 2012, or SQL Server 2014.