Hello Dan Hecht,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/6768
to look at the new patch set (#3).
Change subject: IMPALA-5273: Replace StringCompare with glibc memcmp
......................................................................
IMPALA-5273: Replace StringCompare with glibc memcmp
glibc's memcmp, which dispatches dynamically based on the instructions
the processor supports, uses sse4.1's ptest, which is faster than our
implementation.
I ran a the benchmark below. The final query sped up by about 5x with
this patch.
create table long_strings (s string) stored as parquet;
insert into long_strings values (repeat("a", 2048));
insert into long_strings select a.s from long_strings a,
long_strings b;
insert into long_strings select a.s from long_strings a,
long_strings b;
insert into long_strings select a.s from long_strings a,
long_strings b;
insert into long_strings select a.s from long_strings a,
long_strings b;
insert into long_strings select a.s from long_strings a,
long_strings b;
insert into long_strings select a.s from long_strings a,
(select * from long_strings limit 10) b;
select count(*) from long_strings where s <= repeat("a", 2048);
Change-Id: Ie4786a4a75fdaffedd6e17cf076b5368ba4b4e3e
---
M be/src/benchmarks/string-compare-benchmark.cc
M be/src/runtime/string-value.inline.h
2 files changed, 54 insertions(+), 165 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/68/6768/3
--
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Ie4786a4a75fdaffedd6e17cf076b5368ba4b4e3e
Gerrit-PatchSet: 3
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Jim Apple <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Jim Apple <[email protected]>
Gerrit-Reviewer: Mostafa Mokhtar <[email protected]>
