Taras Bobrovytsky has posted comments on this change. Change subject: IMPALA-4939, IMPALA-4939: Decimal V2 multiplication ......................................................................
Patch Set 4: (1 comment) http://gerrit.cloudera.org:8080/#/c/7438/4//COMMIT_MSG Commit Message: Line 75: DECIMAL_V2 disabled: 2.65s > So we go down this path for multiplies that overflow, or are close to overf Running perf top showed that most of the time is spent in ScaleDownAndRound<int256_t, int256_t>(). It looks like it's the division (of one int256 by another int256) that is taking the most time. I also noticed that disabling the codegen slows down the query in the BEFORE case by ~10x. So the performance difference before my patch and after is huge only when codegen is enabled. Otherwise, it's like a 3x difference. (Do you think it's most likely due to the scanner being much faster in the codegen case?) -- To view, visit http://gerrit.cloudera.org:8080/7438 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I37ad6232d7953bd75c18dc86e665b2b501a1ebe1 Gerrit-PatchSet: 4 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: Taras Bobrovytsky <tbobrovyt...@cloudera.com> Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com> Gerrit-Reviewer: Michael Ho <k...@cloudera.com> Gerrit-Reviewer: Taras Bobrovytsky <tbobrovyt...@cloudera.com> Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com> Gerrit-Reviewer: Zach Amsden <zams...@cloudera.com> Gerrit-HasComments: Yes
