Space used in clustered index for variable-length data types?


msdn resources little unclear on this: if variable-length data type column (e.g. varchar(255)) used in clustered index, how space should used calculate size of index - average length of data in column or max length?

varchar columns allocate amount of space needed store the current data (plus 2 bytes overhead). therefore, best estimation use average length of data in column (plus 2 bytes overhead).
thanks
mirek

 



SQL Server  >  SQL Server Database Engine



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