NSURLConnection记忆不断增加

Question

以下代码每4秒触发一次请求。

aUrl = [NSURL URLWithString:printUrl];
request = [NSMutableURLRequest requestWithURL:aUrl cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:60.0];

//MAKE REQUEST
[request setHTTPMethod:@"POST"];

postString = [NSString stringWithFormat:@"h=%@&app=%@v%@&ios=true", hash,iosVersion,version];
[request setHTTPBody:[postString dataUsingEncoding:NSUTF8StringEncoding]];

_connectionFetch = [NSURLConnection connectionWithRequest:request delegate:self];

我正在使用ARC而且我对obj c很新。当你经常调用nsurlconnection时，你可以很容易地看到内存增加：

for (int i = 0; i<=10; i++) {
   _connectionFetch = [NSURLConnection connectionWithRequest:request delegate:self];     
}

在委托中didFailWithError，didReceiveData，didReceiveResponse，connectionDidFinishLoading我用

释放变量

_connectionFetch = nil;

我也在清除缓存并禁用它：

[[NSURLCache sharedURLCache] removeAllCachedResponses];
[[NSURLCache sharedURLCache] setMemoryCapacity:0];
[[NSURLCache sharedURLCache] setDiskCapacity:0];

现在的问题是，经过一段时间后，触发URL获取的逻辑停止工作。可能是因为分配了太多内存。内存周期性增加：