Details
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Improvement
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Status: Closed
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Major
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Resolution: Incomplete
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None
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Description
SocketTimeoutException is currently treated like any IOE inside of HCM.getRegionServerWithRetries and I think this is a problem. This method should only do retries in cases where we are pretty sure the operation will complete, but with STE we already waited for (by default) 60 seconds and nothing happened.
I found this while debugging Douglas Campbell's problem on the mailing list where it seemed like he was using the same scanner from multiple threads, but actually it was just the same client doing retries while the first run didn't even finish yet (that's another problem). You could see the first scanner, then up to two other handlers waiting for it to finish in order to run (because of the synchronization on RegionScanner).
So what should we do? We could treat STE as a DoNotRetryException and let the client deal with it, or we could retry only once.
There's also the option of having a different behavior for get/put/icv/scan, the issue with operations that modify a cell is that you don't know if the operation completed or not (same when a RS dies hard after completing let's say a Put but just before returning to the client).