# Scheduling: Executing a Schedule

![`smart`](ExecutingScheduling_aa_003_20220509.png)

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The Operator created in PD does not immediately start issuing and execution, but instead enters a wait queue first. According to the configuration, the Operator is removed from the waiting queue at a certain concurrency and executed. The process of execution is to send each step of the Operator to the Leader of the corresponding Region in turn.

When the Operator finishes executing, it is marked as finish or the timeout is marked as timeout and removed from the execution list.