The cost estimate for processing a cursor is calculated at declare cursor time for all cursors except execute cursors, which is calculated when the cursor opens.
Pre-execution time resource limits on I/O cost are enforced at open cursorname time for all cursor types. The optimizer recalculates the limit value each time the user attempts to open the cursor.
An execution time resource limit applies to the cumulative I/O cost of a cursor from the time the cursor opens to the time it closes. The optimizer recalculates the I/O limit each time a cursor opens.
For a discussion of cursors, see Chapter 18, “Cursors: Accessing Data Row by Row,” in the Transact-SQL User’s Guide.
