Ashwani Raina has posted comments on this change. ( http://gerrit.cloudera.org:8080/24328 )
Change subject: KUDU-3429 Make rows per block flag based (1/n) ...................................................................... Patch Set 1: (2 comments) http://gerrit.cloudera.org:8080/#/c/24328/1/src/kudu/tablet/compaction.cc File src/kudu/tablet/compaction.cc: http://gerrit.cloudera.org:8080/#/c/24328/1/src/kudu/tablet/compaction.cc@94 PS1, Line 94: rowset_compaction_rows_per_block > Is there lower/upper limits that make sense for this flag? A lower limit should be at least 1 to allow compaction block preparation work. For upper limit, we can keep it at 100 for now. I am using 10K in the unit tests(not yet published) to trigger OOM. Will revisit the upper limit if required. http://gerrit.cloudera.org:8080/#/c/24328/1/src/kudu/tablet/compaction.cc@97 PS1, Line 97: increasing peak RSS at the cost of higher memory " : "usage per operation. > Higher memory usage is the cost, but what is the _benefit_ of a higher sett A larger value amortizes the per-block I/O overhead i.e. it will have fewer NextBlock calls, better sequential read patterns, etc at the cost of inflated RSS usage. Peak memory is dependent on three factors - number of rowsets (picked for compaction), number of rows per batch and (undo + redo) delta mutations. Even if we choose low number of rows per block, it will help reduce the peak usage. However, with ultra-high number of mutations per row/s, reducing the rows per block may only help to certain extent. -- To view, visit http://gerrit.cloudera.org:8080/24328 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I65f1e0d91e718b097bcc6e3979f246a13a618edf Gerrit-Change-Number: 24328 Gerrit-PatchSet: 1 Gerrit-Owner: Ashwani Raina <[email protected]> Gerrit-Reviewer: Alexey Serbin <[email protected]> Gerrit-Reviewer: Ashwani Raina <[email protected]> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Comment-Date: Fri, 29 May 2026 11:01:32 +0000 Gerrit-HasComments: Yes
