# Limit Parameters

| Parameter                   | Default | Description                                                                                                            |
| :-------------------------- | :------ | :--------------------------------------------------------------------------------------------------------------------- |
| `region-schedule-limit`     | 2048    | The number of region scheduling tasks allowed at the same time.                                                        |
| `leader-schedule-limit`     | 4       | The number of leader scheduling tasks allowed at the same time.                                                        |
| `replica-schedule-limit`    | 64      | The number of replica scheduling tasks allowed at the same time.                                                       |
| `merge-schedule-limit`      | 8       | The number of region merge scheduling tasks allowed at the same time. Set this parameter to 0 to disable region merge. |
| `hot-region-schedule-limit` | 4       | Controls the number of hot region scheduling tasks allowed at the same. It is independent of the region scheduling.    |

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Schedule the limit parameter

Currently, there are 5 kinds of limits for PD, which are used to control the generation speed of related operators, indicating how many operators of this type can be executed at the same time at the same time. The faster the store consumes, the more it executes per unit of time.

- leader-schedule-limit
- replica-schedule-limit
- merge-schedule-limit
- region-schedule-limit
- hot-region-schedule-limit

The above five parameters are used to control the generation speed of the global operator. In order to limit the scheduling speed (consumption speed) of each store, the 3.0 version introduces the store limit setting, which currently includes limiting the speed limit of addPeer and RemovePeer operations, which can control the scheduling speed more accurately