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0 pointsadra1y ago0 comments

It's not great, but you can always catch and retry if your belief is that the GC will free enough memory to allow the attempt to continue after the memory pressure subsides.

Let's say you get 1/100 requests that are randomly sent to your process. That 1 takes 100x the average memory usage of the others. You could spin it out to different services to better handle the weird one-off, but that doesn't always make sense. Sometimes you just need to be ok with working the 100x job and let the other 99 get progressive falloff retry. Different solutions are always possible.

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Quekid51y ago

> It's not great, but you can always catch and retry if your belief is that the GC will free enough memory to allow the attempt to continue after the memory pressure subsides.

No, you cannot. Catching, for example, StackOverflowError (which inherits from Error) can lead to very strange deadlocks and such (if locking is relying on try-finally discipline, as it should), even if you do "almost nothing" before re-throwing.

It's a huge hornet's nest of weirdness to even attempt to catch anything which derives directly from Error. (Rather than RuntimeException/Exception.)

EDIT: There are some really strange subclasses of Error now that I think about it. E.g. VirtualMachineError ... I don't think I've ever seen that in any logs, thankfully, but what exactly is the program (running on the failing VM) supposed to do if that is thrown? It'd be like trying to carry on or log an error if suddenly 1==2 turned out to be true.

delusional1y ago

> There are some really strange subclasses of Error now that I think about it. E.g. VirtualMachineError

An OutOfMemoryError is a VirtualMachineError. The Java runtime doesn't technically contain the idea of "finite memory". The language sort of assumes there's an infinite amount of memory. When there isn't and the VM is forced to throw an OutOfMemoryError it's technically a breach of the abstraction of the language and the VM is unable to continue working.

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