TIMI[NG] [START text | SHOW | STOP]
Records timing data for an elapsed period of time, lists the current timer's name and timing data, or lists the number of active timers.
START text
Sets up a timer and makes text the name of the timer. You can have more than one active timer by STARTing additional timers before STOPping the first; SQL*Plus nests each new timer within the preceding one. The timer most recently STARTed becomes the current timer.
SHOW
Lists the current timer's name and timing data.
STOP
Lists the current timer's name and timing data, then deletes the timer. If any other timers are active, the next most recently STARTed timer becomes the current timer.
Enter TIMING with no clauses to list the number of active timers. For other information about TIMING, see SET AUTOTRACE