make parameters more reasonable

[nolouch]

Feature Request

Describe your feature request related problem

We have encountered many problems caused by improper parameter adjustment. We must limit the adjustment range of the parameters and give a best practice, remove some useless and do some check.

Such as: merge-limit=128, region-limit=64, leader-limit=8 the merge limit may influence the leader limit.

Describe alternatives you've considered

• make the limit do not affect each other
• limit the adjustment range, such as store limit should have best practice
• do some check if the user set parameters is unreasonble

Teachability, Documentation, Adoption, Migration Strategy

• GO

[xuhui-lu]

hey @nolouch, may I pick up this issue?

[xuhui-lu]

And I think the limit here means the parameters for scheduler, is my understanding correct?

[nolouch]

@xuhui-lu Yes, you are right. such as store limit. we need to set a reasonable range for some parameters. Do you have any ideas?
PTAL @rleungx @bufferflies

[bufferflies]

I think you should decouple the merge-limit, region-limit, leader-limit first.

[bufferflies]

The relation between limit and scheduler(checker) is below:

the relation between opKind and scheduler(checker) is below:

[bufferflies]

There are some job to solve this problem:

• one operator only consume one limit, it will consume leader limit if operator include transfer leader and move peer
• add leader store limit to modify one store's leader limit independent.