Issue 1:
I have searched the issues of this repository and believe that this is not a duplicate.

I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

Dubbo version: 2.6.1

Operating System version: win10 64位

Java version: openjdk-1.8.0.212-3

Steps to reproduce this issue

在IDE中直接运行main函数不会出这个异常，但是打包成jar包之后，执行jar包就会出现。

项目地址 https://github.com/sniperking1234/dubbo-kubernetes

pom 路径 /demo/demo-provider/pom.xml

If there is an exception, please attach the exception trace:

Exception in thread "main" java.lang.IllegalStateException: No such extension com.alibaba.dubbo.rpc.Protocol by name dubbo
at com.alibaba.dubbo.common.extension.ExtensionLoader.findException(ExtensionLoader.java:482)
at com.alibaba.dubbo.common.extension.ExtensionLoader.createExtension(ExtensionLoader.java:489)
at com.alibaba.dubbo.common.extension.ExtensionLoader.getExtension(ExtensionLoader.java:309)
at com.alibaba.dubbo.config.ServiceConfig.findConfigedPorts(ServiceConfig.java:636)
at com.alibaba.dubbo.config.ServiceConfig.doExportUrlsFor1Protocol(ServiceConfig.java:470)
at com.alibaba.dubbo.config.ServiceConfig.doExportUrls(ServiceConfig.java:357)
at com.alibaba.dubbo.config.ServiceConfig.doExport(ServiceConfig.java:316)
at com.alibaba.dubbo.config.ServiceConfig.export(ServiceConfig.java:215)
at com.alibaba.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:121)
at com.alibaba.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:50)
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:167)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:393)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:347)
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:883)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:93)
at com.alibaba.dubbo.demo.provider.Provider.main(Provider.java:11)

Issue 2:
I have searched the issues of this repository and believe that this is not a duplicate.

I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

Dubbo version: 2.6.2

Operating System version: mac os 10.13.4

Java version: jdk8

Steps to reproduce this issue

I have 300 provider instance; so i set 2000 virutal nodes;

when the quantity of provider changed, consumer need to refresh the "ConsistentHashSelector"; if the qps is 200, consumer will create 200 "ConsistentHashSelector" ;

it cost 300ms to create a "ConsistentHashSelector" with 2000 virtual nodes and 300 providers；

com.alibaba.dubbo.rpc.cluster.loadbalance.ConsistentHashLoadBalance

set hash.nodes = 2000；

deploy 3 providers, every provider use consistentHash loadbalance

consumer set timeout as 100ms ，test qps is 100， deploy the forth provider, the thread in cusumer will be blocked。

Pls. provide [GitHub address] to reproduce this issue.

Expected Result

What do you expected from the above steps？

Actual Result

What actually happens?

If there is an exception, please attach the exception trace:

Just put your stack trace here!