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From "Taras Bobrovytsky (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-5017: Error on decimal overflow
Date Fri, 27 Oct 2017 00:55:41 GMT
Taras Bobrovytsky has uploaded this change for review. ( http://gerrit.cloudera.org:8080/8404


Change subject: IMPALA-5017: Error on decimal overflow
......................................................................

IMPALA-5017: Error on decimal overflow

Before this patch, decimal operations would either silently overflow (in
the case of sum() and avg()), or produce a warning.

In this patch, the beharior is changed so that an error is produced in
the case of overflow when DECIMAL_v2 is enabled. Decimal v1 behavior is
unchanged.

We introduce overflow checks when computing sum() and avg(). This
results in a ~30% performance regression when we are in decimal v2 mode
compared to decimal v1.

Benchmarks:
  Query:
  select sum(dec_38_19) from decimal_tbl
    Decimal v1: 13.09s
    Decimal v2: 17.10s

  Query:
  select avg(dec_38_19) from decimal_tbl
    Decimal v1: 13.60s
    Decimal v2: 19.10s

Testing:
- Added several end to end tests.
- Updated Expr tests to check for error in case of overflow.

Change-Id: Id98a92c9a9469ec8cf14e518c741a2dab7053019
---
M be/src/exprs/aggregate-functions-ir.cc
M be/src/exprs/decimal-operators-ir.cc
M be/src/exprs/expr-codegen-test.cc
M be/src/exprs/expr-test.cc
M testdata/workloads/functional-query/queries/QueryTest/decimal-exprs.test
M testdata/workloads/functional-query/queries/QueryTest/decimal.test
6 files changed, 186 insertions(+), 69 deletions(-)



  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/04/8404/1
-- 
To view, visit http://gerrit.cloudera.org:8080/8404
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: Id98a92c9a9469ec8cf14e518c741a2dab7053019
Gerrit-Change-Number: 8404
Gerrit-PatchSet: 1
Gerrit-Owner: Taras Bobrovytsky <tbobrovytsky@cloudera.com>

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