INF: How DATALENGTH Determines the Length of Text Fields

ID: Q75277

The information in this article applies to:

Microsoft SQL Server for OS/2, version 4.2
Microsoft SQL Server version 4.2x

The DATALENGTH function does not need to traverse the entire text page chain to determine how long the text field is, because the length is stored on the first page in the chain. Therefore, although SQL Server must de-reference the pointer stored in the row on the data page to determine the location of the text page, then read the text page, the overhead is small.

Additional query words: de-reference Windows NT dblib


Keywords          : kbprg SSrvDB_Lib SSrvServer SSrvWinNT 
Version           : 4.2 | 4.2
Platform          : OS/2 WINDOWS 
Issue type        :

Last Reviewed: March 11, 1999