Tim Armstrong 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 > It takes time to convert a number from 128 bits to 256 bits. Also, Boost do So we go down this path for multiplies that overflow, or are close to overflowing? I'd be less concerned if the multiply itself was 4x slower in isolation, but 10x end-to-end slowdown implies that the slowdown of the operation in isolation is more than 10x, probably a lot more. It seems like we should be able to do much better than that. Might be worth doing some profiling to understand where the cycles are going. This is dominating query runtime so much you could probably see what's happening with disable_codegen=true and perf top if you run the query in a loop. -- 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 <[email protected]> Gerrit-Reviewer: Dan Hecht <[email protected]> Gerrit-Reviewer: Michael Ho <[email protected]> Gerrit-Reviewer: Taras Bobrovytsky <[email protected]> Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-Reviewer: Zach Amsden <[email protected]> Gerrit-HasComments: Yes
