Lars Volker has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/12065 )

Change subject: IMPALA-5843: Use page index in Parquet files to skip pages
......................................................................


Patch Set 9:

> (54 comments)
 >
 > In a few comments the row group level profile counters came up.
 > Whether we should only have "NumStatsFilteredRowGroups" and count
 > row groups that are filtered out by either row group-level stats or
 > page-level stats.
 > Or, we should have multiple variants of that counter, counting the
 > row group-level and page-level filtering separately. What do you
 > think? For debugging it's good to have more fine-grained data, but
 > I'm not sure that the query profile is the right place for such
 > information.

I think having counter for row groups filtered based on row group stats, and 
pages filtered based on page stats would be good (and sufficient). I think 
entire row groups filtered by page stats (but not row group stats) are not 
worth tracking in a separate counter. The distinction I'd make is whether we 
discarded a row group without looking at the index or not.


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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I0cc99f129f2048dbafbe7f5a51d1ea3a5005731a
Gerrit-Change-Number: 12065
Gerrit-PatchSet: 9
Gerrit-Owner: Zoltan Borok-Nagy <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Lars Volker <[email protected]>
Gerrit-Reviewer: Michael Ho <[email protected]>
Gerrit-Reviewer: Pooja Nilangekar <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Reviewer: Zoltan Borok-Nagy <[email protected]>
Gerrit-Comment-Date: Tue, 09 Apr 2019 21:55:19 +0000
Gerrit-HasComments: No

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