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From "Zach Amsden (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-5036: Parquet count star optimization
Date Tue, 13 Jun 2017 17:19:56 GMT
Zach Amsden has posted comments on this change.

Change subject: IMPALA-5036: Parquet count star optimization
......................................................................


Patch Set 3:

(3 comments)

http://gerrit.cloudera.org:8080/#/c/6812/3/be/src/exec/hdfs-parquet-scanner.cc
File be/src/exec/hdfs-parquet-scanner.cc:

Line 445:       *dst_slot = file_metadata_.row_groups[row_group_idx_].num_rows;
Bounds check against file_metadata_.num_rows (i.e. keep a running counter as below in row_group_rows_read_
and DCHECK_LE(row_group_rows_read_, file_metatdata_.num_rows)?


Line 454:   if (scan_node_->IsZeroSlotTableScan()) {
Why is this optimization not redundant now?  Maybe update the comment to indicate the type
of query this now will operate on:

  e.g., select 1 from table


http://gerrit.cloudera.org:8080/#/c/6812/3/common/thrift/PlanNodes.thrift
File common/thrift/PlanNodes.thrift:

Line 226:   11: optional i64 parquet_count_star_slot_offset
> i32 right?
Would it be simpler to have this be one parameter and indicate truth by passing a value >=
0?


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Gerrit-MessageType: comment
Gerrit-Change-Id: I536b85c014821296aed68a0c68faadae96005e62
Gerrit-PatchSet: 3
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Lars Volker <lv@cloudera.com>
Gerrit-Reviewer: Marcel Kornacker <marcel@cloudera.com>
Gerrit-Reviewer: Mostafa Mokhtar <mmokhtar@cloudera.com>
Gerrit-Reviewer: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Gerrit-Reviewer: Zach Amsden <zamsden@cloudera.com>
Gerrit-HasComments: Yes

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