Hello Vihang Karajgaonkar,

I'd like you to do a code review. Please visit

    http://gerrit.cloudera.org:8080/13251

to review the following change.


Change subject: IMPALA-8369 (part 4): Hive 3: fixes for functional dataset 
loading
......................................................................

IMPALA-8369 (part 4): Hive 3: fixes for functional dataset loading

This fixes three issues for functional dataset loading:

- works around HIVE-21675, a bug in which 'CREATE VIEW IF NOT EXISTS'
  does not function correctly in our current Hive build. This has been
  fixed already, but the workaround is pretty simple, and actually the
  'drop and recreate' pattern is used more widely for data-loading than
  the 'create if not exists' one.

- adds the ability to specify version restrictions for tables to load.
  The restrictions use the Python "requirements.txt" syntax. This new
  functionality is used to skip creating a hive "INDEX" table on Hive 3,
  where this functionality has been removed.

- Moving from MR to Tez execution changed the behavior of data loading by
  disabling the auto-merging of small files. With Hive-on-MR, this
  behavior defaulted to true, but with Hive-on-Tez it defaults false. The
  change is likely motivated by the fact that Tez automatically groups
  small splits on the _input_ side and thus is less likely to produce lots
  of small files. However, that grouping functionality doesn't work
  properly in localhost clusters (TEZ-3310) so we aren't seeing the
  benefit. So, this patch enables the post-process merging of small
  files.

  Prior to this change, the 'alltypesaggmultifilesnopart' test table was
  getting 40+ files inside it, which broke various planner tests. With the
  change, it gets the expected 4 files.

Change-Id: Ic34930dc064da3136dde4e01a011d14db6a74ecd
---
M fe/src/test/resources/hive-site.xml.py
M testdata/bin/generate-schema-statements.py
M testdata/bin/load-dependent-tables.sql
M testdata/datasets/README
M testdata/datasets/functional/functional_schema_template.sql
5 files changed, 119 insertions(+), 24 deletions(-)



  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/51/13251/1
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: Ic34930dc064da3136dde4e01a011d14db6a74ecd
Gerrit-Change-Number: 13251
Gerrit-PatchSet: 1
Gerrit-Owner: Todd Lipcon <t...@apache.org>
Gerrit-Reviewer: Vihang Karajgaonkar <vih...@cloudera.com>

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