leventov commented on a change in pull request #7185: Avoid many unnecessary materializations of collections of 'all segments in cluster' cardinality URL: https://github.com/apache/incubator-druid/pull/7185#discussion_r263404675
########## File path: server/src/main/java/org/apache/druid/server/coordinator/helper/DruidCoordinatorBalancer.java ########## @@ -180,7 +180,18 @@ private void balanceTier( //noinspection ForLoopThatDoesntUseLoopVariable for (int iter = 0; (moved + unmoved) < maxSegmentsToMove; ++iter) { final BalancerSegmentHolder segmentToMoveHolder = strategy.pickSegmentToMove(toMoveFrom); - if (segmentToMoveHolder != null && params.getAvailableSegments().contains(segmentToMoveHolder.getSegment())) { + if (segmentToMoveHolder == null) { + log.info("All servers to move segments from are empty, ending run."); + break; + } + // DruidCoordinatorRuntimeParams.getAvailableSegments originate from MetadataSegmentManager, i. e. that's a + // "desired" or "theoretical" set of segments. segmentToMoveHolder.getSegment originates from ServerInventoryView, + // i. e. that may be any segment that happens to be loaded of some server, even if it "shouldn't" from the + // "theoretical" point of view (Coordinator closes such discrepancies eventually via + // DruidCoordinatorCleanupUnneeded). Therefore the picked segmentToMoveHolder's segment may not need to be + // balanced. + boolean needToBalacePickedSegment = params.getAvailableSegments().contains(segmentToMoveHolder.getSegment()); Review comment: Thanks, fixed the typo. I like to keep it a little on the verbose side. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org For additional commands, e-mail: commits-h...@druid.apache.org