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Posted to reviews@impala.apache.org by "Zach Amsden (Code Review)" <ge...@cloudera.org> on 2017/02/18 02:25:46 UTC

[Impala-ASF-CR] IMPALA-2020: Inline big number strings

Zach Amsden has uploaded a new patch set (#5).

Change subject: IMPALA-2020: Inline big number strings
......................................................................

IMPALA-2020: Inline big number strings

We can directly spcecify these in the header instead of keeping the
constants out in a .o.  This lets the compiler inline them in a lot
more places, potentially giving better behavior than a table lookup
by directly inserting the constant.  This in turn allows divides by
now known compile time constants to be converted into multiply.
Avoiding the table lookup seems to be a win for other types as well,
giving anywhere from 18% to ~33% speedup over baseline.

This is likely to become even more imporant with big integer divide,
which requires additional computation for DECIMAL_V2.

Testing: Compare the binary output of decimal-util.cc before and
after; ran expr test suite.

Before:

[localhost:21000] > select sum(cast(cast(l_extendedprice as double) as
decimal(14,2))) from tpch10_parquet.lineitem;
Query: select sum(cast(cast(l_extendedprice as double) as
decimal(14,2))) from tpch10_parquet.lineitem
Query submitted at: 2017-02-18 01:23:54 (Coordinator:
http://impala-dev:25000)
Query progress can be monitored at:
http://impala-dev:25000/query_plan?query_id=f0410a35e981a86b:e6d9207000000000
+-------------------------------------------------------------+
| sum(cast(cast(l_extendedprice as double) as decimal(14,2))) |
+-------------------------------------------------------------+
| 2293813121802.09                                            |
+-------------------------------------------------------------+
Fetched 1 row(s) in 0.83s

After:

[localhost:21000] > select sum(cast(cast(l_extendedprice as double) as
decimal(14,2))) from tpch10_parquet.lineitem;
Query: select sum(cast(cast(l_extendedprice as double) as
decimal(14,2))) from tpch10_parquet.lineitem
Query submitted at: 2017-02-18 02:23:33 (Coordinator:
http://impala-dev:25000)
Query progress can be monitored at:
http://impala-dev:25000/query_plan?query_id=97438c98a3d950a4:1a45eeb900000000
+-------------------------------------------------------------+
| sum(cast(cast(l_extendedprice as double) as decimal(14,2))) |
+-------------------------------------------------------------+
| 2293813121802.09                                            |
+-------------------------------------------------------------+
Fetched 1 row(s) in 0.63s

Change-Id: I5095a366d914cebb0b64bd434a08dbb55c90ed30
---
M be/src/benchmarks/overflow-benchmark.cc
M be/src/common/init.cc
M be/src/exprs/expr-value.h
M be/src/runtime/decimal-test.cc
M be/src/util/CMakeLists.txt
D be/src/util/decimal-util.cc
M be/src/util/decimal-util.h
7 files changed, 20 insertions(+), 50 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/02/5902/5
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I5095a366d914cebb0b64bd434a08dbb55c90ed30
Gerrit-PatchSet: 5
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Zach Amsden <za...@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dh...@cloudera.com>
Gerrit-Reviewer: Jim Apple <jb...@apache.org>
Gerrit-Reviewer: Michael Ho
Gerrit-Reviewer: Zach Amsden <za...@cloudera.com>