Invalidates the specified in-row text pointer, or all in-row text pointers, in the transaction. sp_invalidate_textptr can be used only on in-row text pointers. These pointers are from tables that have the text in row option enabled.
SQL Server allows for a maximum of 1,024 active valid in-row text pointers per transaction per database; however, a transaction spanning more than one database can have 1,024 in-row text pointers in each database. sp_invalidate_textptr can be used to invalidate in-row text pointers and, therefore, free space for additional in-row text pointers.
For more information about the text in row option, see sp_tableoption (Transact-SQL).