Todd Lipcon has posted comments on this change. ( http://gerrit.cloudera.org:8080/13666 )
Change subject: KUDU-2866. Optimize CFileSet::Iterator::FinishBatch ...................................................................... Patch Set 2: (2 comments) http://gerrit.cloudera.org:8080/#/c/13666/2//COMMIT_MSG Commit Message: http://gerrit.cloudera.org:8080/#/c/13666/2//COMMIT_MSG@16 PS2, Line 16: will only be prepared once > Most likely I'm missing something, but from breefly looking into the implem Currently I think we are limited to a single predicate per column, since ScanSpec::predicates_ is a map from column name to single ColumnPredicate instance. In the case where we have multiple predicates on the same column, we currently always merge them. Then in MaterializeBlock(), we will only materialize each column once, because we separate the columns into those with predicates and those without. Test coverage so far seems to agree. But I might believe that we have a lack of coverage and I missed something. Any idea of how we might produce the situation you're worried about? http://gerrit.cloudera.org:8080/#/c/13666/2/src/kudu/tablet/cfile_set.cc File src/kudu/tablet/cfile_set.cc: http://gerrit.cloudera.org:8080/#/c/13666/2/src/kudu/tablet/cfile_set.cc@470 PS2, Line 470: prepared_iters_.clear(); > nit: does it make sense to add I don't think we'd gain much from that, since 'clear' doesn't actually shrink the backing array. So, if on the first batch, we do end up using the full list of iters here, it'll keep that same "shape" across iterations. I could see doing that in CFileSet::Iterator::Init, though. I'll add it there. -- To view, visit http://gerrit.cloudera.org:8080/13666 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I997fe832fdfa8d92fbbcb5d7c5bd4141e485b4f8 Gerrit-Change-Number: 13666 Gerrit-PatchSet: 2 Gerrit-Owner: Todd Lipcon <[email protected]> Gerrit-Reviewer: Alexey Serbin <[email protected]> Gerrit-Reviewer: Grant Henke <[email protected]> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Reviewer: Tidy Bot (241) Gerrit-Reviewer: Todd Lipcon <[email protected]> Gerrit-Comment-Date: Tue, 18 Jun 2019 22:53:52 +0000 Gerrit-HasComments: Yes
