Calculate the I/O Cost of a Cursor

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.

Preexecution 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.

See Transact-SQL Users Guide > Cursors: Accessing Data.