Dan Hecht has posted comments on this change. Change subject: IMPALA-5036: Parquet count star optimization ......................................................................
Patch Set 5: (4 comments) http://gerrit.cloudera.org:8080/#/c/6812/5/fe/src/main/java/org/apache/impala/catalog/BuiltinsDb.java File fe/src/main/java/org/apache/impala/catalog/BuiltinsDb.java: Line 886: prefix + "8InitZeroIN10impala_udf9BigIntValEEEvPNS2_15FunctionContextEPT_", rather than defining a new builtin, why don't we wrap the sum() with a coalesce or isnull? does that not work for some reason? http://gerrit.cloudera.org:8080/#/c/6812/5/fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java File fe/src/main/java/org/apache/impala/planner/HdfsScanNode.java: PS5, Line 105: The caller passes in a flag to the constructor that indicates if the count(*) : * optimization can be applied to the query block of this scan. This scan node decides : * whether to apply the optimization or not This doesn't make a lot of sense to me. On one hand, it sayst he caller decides, but then it says that this node also decides. What's actually going on? Line 109: * do we actually explain in some comment how this optimization works at a high level? PS5, Line 140: This : // scan does additional analysis in init() to determine whether it is correct to apply : // the optimization. this seems to contradict the comment above that says the caller passes a flag to the constructor that indicates whether the optimization can be applied. -- To view, visit http://gerrit.cloudera.org:8080/6812 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I536b85c014821296aed68a0c68faadae96005e62 Gerrit-PatchSet: 5 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: Taras Bobrovytsky <tbobrovyt...@cloudera.com> Gerrit-Reviewer: Alex Behm <alex.b...@cloudera.com> Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com> Gerrit-Reviewer: Lars Volker <l...@cloudera.com> Gerrit-Reviewer: Marcel Kornacker <mar...@cloudera.com> Gerrit-Reviewer: Mostafa Mokhtar <mmokh...@cloudera.com> Gerrit-Reviewer: Taras Bobrovytsky <tbobrovyt...@cloudera.com> Gerrit-Reviewer: Zach Amsden <zams...@cloudera.com> Gerrit-HasComments: Yes
