impala-reviews mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jim Apple (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-2020: Inline big number strings
Date Sat, 18 Feb 2017 03:12:37 GMT
Jim Apple has posted comments on this change.

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


Patch Set 5:

(8 comments)

http://gerrit.cloudera.org:8080/#/c/5902/5//COMMIT_MSG
Commit Message:

PS5, Line 27: 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
elide


PS5, Line 38: 0.83s
error bars?


http://gerrit.cloudera.org:8080/#/c/5902/5/be/src/exprs/expr-value.h
File be/src/exprs/expr-value.h:

Line 177:             decimal4_val = +DecimalUtil::MAX_UNSCALED_DECIMAL4;
> Unary plus necessary to convert to an Rvalue
Why do you want to convert it to an Rvalue? Just to avoid having to define it in a .cc file?
If so, does defining (not declaring or initializing) in a .cc file slow down performance?

Also, add that comment in the file for future readers.


http://gerrit.cloudera.org:8080/#/c/5902/5/be/src/util/decimal-util.h
File be/src/util/decimal-util.h:

Line 57:   template<typename T>
Describe what it does.

Maybe call it Pow10 and call the parameter exponent?

private:


PS5, Line 58: T
Always is_integral?


PS5, Line 59: boost::
static_assert is now part of the language, but I'm not sure if it works on parameters, since
parameters can't be constexpr.


Line 60:     return scale == 0 ? 1 : 10 * GetConstScaleMultiplier<T>(scale-1);
Check for no overflow, if it can be done simply.


Line 136:   if (__builtin_const_p(scale) && p < 10) return GetConstScaleMultiplier<int32_t>(scale);
Does this by itself speed anything up? If scale is constant at compile time, since this is
inlined, won't it just inline to the right value?

https://godbolt.org/g/Tlfl8l


-- 
To view, visit http://gerrit.cloudera.org:8080/5902
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-MessageType: comment
Gerrit-Change-Id: I5095a366d914cebb0b64bd434a08dbb55c90ed30
Gerrit-PatchSet: 5
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Zach Amsden <zamsden@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhecht@cloudera.com>
Gerrit-Reviewer: Jim Apple <jbapple-impala@apache.org>
Gerrit-Reviewer: Michael Ho
Gerrit-Reviewer: Zach Amsden <zamsden@cloudera.com>
Gerrit-HasComments: Yes

Mime
View raw message