Ashwani Raina has posted comments on this change. ( http://gerrit.cloudera.org:8080/19246 )
Change subject: KUDU-3406 [compaction] Increase chances of compaction for large number deltas ...................................................................... Patch Set 3: Update on the two observations made during testing: 1. Compact rowsets op doesn't reduce the existing number of undo deltas that keep accumulating until it hits limit. e.g. 5 delta blocks remain there but extra ones over and above 5 get compacted. I am currently investigating this. - This is expected because CompactRowSetsOp honours the ancient history threshold before GC can pick those and cleanup. In customer case, the deltas it works on, are of old timestamp, hence those get cleaned-up when CompactRowSetsOp kicks in. 2. CountUndoDeltasForTests used in the fix returns number of undo delta blocks that are being worked up currently. In customer case, such a number is high and can cross beyond the limit (i.e. 100) in short time, given the type and speed workload. In such a case, CompactRowSetsOp will keep kicking-in and ensure all those extra undo deltas are compacted in time and hence accumulation of deltas will not happen. -- To view, visit http://gerrit.cloudera.org:8080/19246 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I2199ae3b777e75b15b60d8ad818cc6adc4f5fa3b Gerrit-Change-Number: 19246 Gerrit-PatchSet: 3 Gerrit-Owner: Ashwani Raina <[email protected]> Gerrit-Reviewer: Abhishek Chennaka <[email protected]> Gerrit-Reviewer: Alexey Serbin <[email protected]> Gerrit-Reviewer: Ashwani Raina <[email protected]> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Reviewer: Tidy Bot (241) Gerrit-Comment-Date: Sun, 20 Nov 2022 21:00:24 +0000 Gerrit-HasComments: No
