Fix over-replication caused by balancing when inventory is not updated yet #13114
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…ator_test_fwrk
kfaraz
commented
Sep 21, 2022
| * Fix Apache #12881 to fix this test. | ||
| */ | ||
| @Test | ||
| public void testBalancingWithStaleInventoryCausesOverReplication() |
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Moved this test to SegmentLoadingTest.testBalancingWithStaleViewDoesNotOverReplicate()
imply-cheddar
approved these changes
Sep 29, 2022
Comment on lines
+295
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| ConcurrentMap<SegmentId, BalancerSegmentHolder> movingSegments = | ||
| currentlyMovingSegments.get(toServer.getTier()); | ||
| movingSegments.put(segmentId, segment); | ||
| final LoadPeonCallback callback = moveSuccess -> movingSegments.remove(segmentId); | ||
| try { | ||
| ConcurrentMap<SegmentId, BalancerSegmentHolder> movingSegments = | ||
| currentlyMovingSegments.get(toServer.getTier()); | ||
| movingSegments.put(segmentId, segment); | ||
| callback = () -> movingSegments.remove(segmentId); | ||
| coordinator.moveSegment( | ||
| params, | ||
| fromServer, | ||
| toServer, | ||
| segmentToMove, | ||
| callback | ||
| ); | ||
| coordinator | ||
| .moveSegment(params, fromServer, toServer, segmentToMove, callback); | ||
| return true; | ||
| } | ||
| catch (Exception e) { | ||
| log.makeAlert(e, StringUtils.format("[%s] : Moving exception", segmentId)).emit(); | ||
| if (callback != null) { | ||
| callback.execute(); | ||
| } | ||
| log.makeAlert(e, "[%s] : Moving exception", segmentId).emit(); | ||
| callback.execute(false); |
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Are these changes fixing something or just style? It looks like just style trying to remove the null check from the callback by moving the work of building it outside of the try is that correct?
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Yes, just a style change for readability.
|
Thanks a lot for the review, @imply-cheddar ! |
abhishekagarwal87
approved these changes
Sep 29, 2022
This was referenced Dec 18, 2022
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Fixes item (1) in #12881
Description
The current implementation of segment balancing often leads to over-replication.
This can happen in the following (fairly common) scenario:
This is a frequent occurrence but under normal circumstances, it is not noticeable
because load rules quickly drop the over-replicated segment from A. But if load rules get
stuck for some reason (e.g. trying to reach target replication levels on a different tier),
the number of over-replicated segments keeps increasing, thereby overloading historicals.
Changes
The HTTP response status is enough to determine load success or failure.
SegmentLoadingNegativeTestMain classes to review:
LoadPeonCallbackDruidCoordinatorCuratorLoadQueuePeonHttpLoadQueuePeonBalanceSegmentsThis PR has: