小编tsu*_*da7的帖子

我正在阅读第4版的"Hadoop The Definitive Guide",并且对YARN'S DRF(第4章,Dominant Resource Fairness)中发现了这个解释

想象一下,一个总共有100个CPU和10 TB内存的集群.应用程序A请求(2个CPU,300 GB)的容器,而应用程序B请求容器(6个CPU,100 GB).A的请求是群集的(2%,3%),因此内存占主导地位,因为其比例(3%)大于CPU(2%).B的要求是(6%,1%),因此CPU占主导地位.由于B的容器请求是主导资源的两倍(6%对3%),因此在公平共享下将分配一半的容器.

我无法理解的意思it will be allocated half as many containers under fair sharing.我猜it这里是Application B,并Application B分配了应用程序A的容器数量的一半.这样对吗？为什么Application B即使需要更多资源,也会分配较小的容器？

对某些解释文件的任何建议和指示都会受到如此多的赞赏.先感谢您.

我正在用jackson开发一个软件，但完全卡住了......当我用java -jar <MY_APPLICATION>.jar命令运行spring-boot程序时，出现以下错误：

...
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.fasterxml.jackson.databind.ObjectMapper]: Factory method 'jacksonObjectMapper' threw exception; nested exception is
java.lang.IllegalAccessError: tried to access method com.fasterxml.jackson.databind.ser.std.StdSerializer.<init>(Ljava/lang/Class;)V from class com.fasterxml.jackson.datatype.jsr310.JavaTimeModule
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189)
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588)
        ... 84 more
Caused by: java.lang.IllegalAccessError: tried to access method com.fasterxml.jackson.databind.ser.std.StdSerializer.<init>(Ljava/lang/Class;)V from class com.fasterxml.jackson.datatype.jsr310.JavaTimeModule
        at com.fasterxml.jackson.datatype.jsr310.JavaTimeModule.<init>(JavaTimeModule.java:159)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at java.lang.Class.newInstance(Class.java:442)
        at org.springframework.beans.BeanUtils.instantiate(BeanUtils.java:78)
        at org.springframework.http.converter.json.Jackson2ObjectMapperBuilder.registerWellKnownModulesIfAvailable(Jackson2ObjectMapperBuilder.java:719)
        at org.springframework.http.converter.json.Jackson2ObjectMapperBuilder.configure(Jackson2ObjectMapperBuilder.java:572)
        at org.springframework.http.converter.json.Jackson2ObjectMapperBuilder.build(Jackson2ObjectMapperBuilder.java:554)
        at org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$JacksonObjectMapperConfiguration.jacksonObjectMapper(JacksonAutoConfiguration.java:87)
        at org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$JacksonObjectMapperConfiguration$$EnhancerBySpringCGLIB$$2434a0bb.CGLIB$jacksonObjectMapper$0(<generated>)
        at org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$JacksonObjectMapperConfiguration$$EnhancerBySpringCGLIB$$2434a0bb$$FastClassBySpringCGLIB$$d685921f.invoke(<generated>)
        at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
        at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:356)
        at …

我需要一个包含多种类型的抽象切片.最简化的代码是:

package main

import "fmt"

type A interface{}

type X string

func main() {
    sliceA := make([]A, 0, 0)
    sliceX := []X{"x1", "x2"}
    var appendedSlice []A
    appendedSlice = append(sliceA, sliceX[0], sliceX[1])  // (1) works
    appendedSlice = append(sliceA, sliceX...)             // (2) doesn't work
    fmt.Println(appendedSlice)

}

在我的真实程序中,接口A定义了一些函数,X和其他类型实现了它.

第(2)行引发错误cannot use sliceX (type []X) as type []A in append.

我认为(2)是(1)的语法糖,但我可能遗漏了一些东西......我是否必须一个一个地将一个元素X添加到切片A中？

提前谢谢你们!