Quanlong Huang has uploaded this change for review. ( 
http://gerrit.cloudera.org:8080/18745


Change subject: IMPALA-11444: Fix wrong results when reading wide rows from ORC
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IMPALA-11444: Fix wrong results when reading wide rows from ORC

After IMPALA-9228, ORC scanner reads rows into scratch batch where we
perform conjuncts and runtime filters. The survived rows will be picked
by the output row batch. We loop this until the output row batch is
filled (1024 rows by default) or we finish reading the ORC batch (1024
rows by default).

Usually the loop will have only 1 iteration since the scratch batch
capacity is also 1024. All rows of the current ORC batch can be
materialized into the scratch batch. However, when reading wide rows
that have tuple size larger than 4096 bytes, the scratch batch capacity
will be reduced to be lower 1024, i.e. the scratch batch can store less
than 1024 rows. In this case, we need more iterations in the loop.

The bug is that we didn't commit rows to the output row batch after each
iteration. The suvived rows will be ovewritten in the second iteration.

This is fixed in a later optimization (IMPALA-9469) which is missing in
the 3.x branch. This patch only pick the fix of it.

Tests:
 - Add test on wide tables with 2K columns

Change-Id: I09f1c23c817ad012587355c16f37f42d5fb41bff
---
M be/src/exec/hdfs-orc-scanner.cc
M tests/query_test/test_scanners.py
2 files changed, 56 insertions(+), 5 deletions(-)



  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/45/18745/1
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Gerrit-Project: Impala-ASF
Gerrit-Branch: 3.x
Gerrit-MessageType: newchange
Gerrit-Change-Id: I09f1c23c817ad012587355c16f37f42d5fb41bff
Gerrit-Change-Number: 18745
Gerrit-PatchSet: 1
Gerrit-Owner: Quanlong Huang <[email protected]>

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