|  | Posted by uli2003wien on 09/14/05 13:30 
Dear group,
 we are running a SQL-Server Database which is about 30 GB large. The
 purpose of this database is to contain periodic data from automatic
 devices which insert values into some tables.
 
 Unfortunately most of these tables don't have a key (and a key can only
 be introduced when the application programmers have changed their
 software). Tables have this structure
 
 deviceno timestamp data
 
 where we expect for every device and timestamp one row of data.
 
 In the ongoing operation it happens that the index of this large table
 gets corrupted and a select from this table yields 2 rows for some
 devices.
 
 In fact a select "SELECT DEVICENO, TIMESTAMP, COUNT(*) FROM TABLE GROUP
 BY DEVICENO, TIMESTAMP HAVING COUNT(*) > 1" returns lots of data.
 
 After rebuild of the indexes the table is "clean" again.
 
 What could cause the index corruption ?
 
 Missing key?
 Faulty application program ?
 a combination of both ?
 
 How can i prevent this from happening again, as long as there is no
 updated database / application ?
 
 I'd be grateful for any useful comment
 
 Regards
 
 Uli
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