Amogh Margoor has uploaded a new patch set (#4). (
http://gerrit.cloudera.org:8080/17303 )
Change subject: IMPALA-10350 Fix precision loss while converting DecimalValue
to double.
......................................................................
IMPALA-10350 Fix precision loss while converting DecimalValue to double.
Original approach to convert DecimalValue(internal representation of decimals)
was not accurate.
It was:
static_cast<double>(value_) / pow(10.0, scale).
However only integers from −2^53 to 2^53 can be represented accurately by
double precision without any loss.
Hence, it would not work for numbers like -0.43149576573887316.
For DecimalValue representing -0.43149576573887316, value_ would be
-43149576573887316 and scale would be 17. As value_ < -2^53, result would
not be accurate. In newer approach we are using third party library
https://github.com/lemire/fast_double_parser, which handles above scenario
in a performant manner.
Change-Id: I56f0652cb8f81a491b87d9b108a94c00ae6c99a1
---
M be/src/runtime/decimal-value.inline.h
A be/src/thirdparty/fast_double_parser/LICENSE
A be/src/thirdparty/fast_double_parser/LICENSE.BSL
A be/src/thirdparty/fast_double_parser/README.md
A be/src/thirdparty/fast_double_parser/fast_double_parser.h
M bin/rat_exclude_files.txt
M testdata/workloads/functional-query/queries/QueryTest/values.test
7 files changed, 1,551 insertions(+), 1 deletion(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/03/17303/4
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I56f0652cb8f81a491b87d9b108a94c00ae6c99a1
Gerrit-Change-Number: 17303
Gerrit-PatchSet: 4
Gerrit-Owner: Amogh Margoor <amarg...@gmail.com>
Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com>
Gerrit-Reviewer: Zoltan Borok-Nagy <borokna...@cloudera.com>
