Problem with Timer control in WebForm

Hi friends,

               i face some problem in Timer control .The problem is I set the timer control interval to 1 minute.In the timer_tick event,  i call 2 or three methods.The method is using oracle and sql database.so the method is somewhat slow.The problem is before the methods in Timer_tick event execute,when the time interval comes to 1 minute,another execution is starting before the methods complete execution.please help me to resolve the problem. Thankyou
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