How does Hadoop process records split across block boundaries?

Interesting question, I spent some time looking at the code for the details and here are my thoughts. The splits are handled by the client by InputFormat.getSplits, so a look at FileInputFormat gives the following info: For each input file, get the file length, the block size and calculate the split size as max(minSize, min(maxSize, … Read more

Returning method object from inside block

You can’t. Embrace the fact that what you’re trying to do is asynchronous and add a completion block parameter to your getMyData method which is called when the inner completion handler is called. (And remove the return from the method signature): – (void)getMyDataWithCompletion:(void(^)(NSData *data))completion { MyUIDocument *doc = [[MyUIDocument alloc] initWithFileURL:fileURL]; [doc openWithCompletionHandler:^(BOOL success) { … Read more

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