1.问题
程序在启动加载时非常慢，后来排查到时这行代码有问题Aws::S3::S3Client client
2.解决办法
在查AWS-SDK-CPP的仓库时，发现也有人提到了类似的问题，可以加个环境变量
先说最后可以做到的解决办法
在代码中添加环境变量或者在我的电脑高级设置中添加
代码语言：javascript复制AWS_EC2_METADATA_DISABLED=true其中在代码中添加时，需要把这个环境变量注册到path中，自己写一个函数
至于原因的话，是构造函数里面的问题，涉及的可能比较多，先不讨论了
3.官方回答
Sorry we are working on a better way to do it but currently the only way to avoid these involve environment variables. If the AWS_EC2_METADATA_DISABLED is problematic for you, you could also set AWS_DEFAULT_REGION or AWS_REGION to your region… Though honestly if having the env variable as true causes troubles later on, the best workaround I can think of is having something like:
代码语言：javascript复制setenv("AWS_EC2_METADATA_DISABLED", "true", 1);
Aws::Client::ClientConfiguration clientConfig("default"); // use this configuration for all aws clients or do the same for other client configurations
setenv("AWS_EC2_METADATA_DISABLED", "false", 1);either that or changing the source code directly- on clientConfiguration.cpp remove lines 127-134. Hope one of these works for you. Ah and also, we have this documented as part of the changes on version 1.8 in our wiki
简单说，要不加上这几行代码，要不就把clientConfiguration.cpp的127-134行代码删除
注意setenv是Linux添加环境变量的方法，windows是这样的
代码语言：javascript复制SetEnvironmentVariable("AWS_EC2_METADATA_DISABLED", "true");但我用windows的方法没用，不知道为什么
另外我在电脑里clientConfiguration.cpp也没有找到
所以最简单的方法，直接在电脑环境变量加上就好
4.参考
c - Aws::S3::S3Client constructor very slow - Stack Overflow
Performance Degradation because of EC2 Metadata Client · Issue #1511 · aws/aws-sdk-cpp (github.com)
Severe Performance Degradation for S3 using SDK 1.8.32 · Issue #1440 · aws/aws-sdk-cpp (github.com)
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