When SQL statements and other types of calls are made to SQL Server, an amount of CPU time is necessary to process the call. Average calls require a small amount of CPU time. However, an SQL statement involving a large amount of data or a runaway query can potentially consume a large amount of CPU time, reducing CPU time available for other processing.
CPU utilization is the most important operating system statistic in the tuning process. Excessive CPU usage usually means that there is little idle CPU on the system. This could be caused by an inadequately-sized system, by untuned SQL statements, or by inefficient application programs.
Because a cursor points to a currently selected set of records, a cursor can be used by only one connection at a time. However, the compiled plan to which the cursor is linked can be used simultaneously by multiple connections.