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Posted to issues-all@impala.apache.org by "Pooja Nilangekar (JIRA)" <ji...@apache.org> on 2018/09/04 20:51:00 UTC
[jira] [Commented] (IMPALA-7367) Pack StringValue, CollectionValue
and TimestampValue slots
[ https://issues.apache.org/jira/browse/IMPALA-7367?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16603589#comment-16603589 ]
Pooja Nilangekar commented on IMPALA-7367:
------------------------------------------
There is an issue with packing TimestampValue. GCC doesn't pack the class because its variables are not explicitly declared as packed. So the compiler complains with the following error for the date_ and time_ attributes:
{code:java}
error: ignoring packed attribute because of unpacked non-POD field
{code}
However, boost::posix_time::time_duration and boost::gregorian::date are indeed packed.This is a known gcc bug [https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60972]. Since the attributes belong to the boost library, I am unaware of any method to explicitly declare them as packed structures. How should we handle this? Would it be acceptable to pack StringValue and CollectionValue for now and create a Jira to track TimestampValue for when the GCC bug gets resolved?
> Pack StringValue, CollectionValue and TimestampValue slots
> ----------------------------------------------------------
>
> Key: IMPALA-7367
> URL: https://issues.apache.org/jira/browse/IMPALA-7367
> Project: IMPALA
> Issue Type: Improvement
> Components: Backend
> Reporter: Tim Armstrong
> Assignee: Pooja Nilangekar
> Priority: Major
> Labels: perfomance
> Attachments: 0001-WIP.patch
>
>
> This is a follow-on to finish up the work from IMPALA-2789. IMPALA-2789 didn't actually fully pack the memory layout because StringValue, TimestampValue and CollectionValue still occupy 16 bytes but only have 12 bytes of actual data. This results in a higher memory footprint, which leads to higher memory requirements and worse performance. We don't get any benefit from the padding since the majority of tuples are not actually aligned in memory anyway.
> I did a quick version of the change for StringValue only which improves TPC-H performance.
> {noformat}
> Report Generated on 2018-07-30
> Run Description: "b5608264b4552e44eb73ded1e232a8775c3dba6b vs f1e401505ac20c0400eec819b9196f7f506fb927"
> Cluster Name: UNKNOWN
> Lab Run Info: UNKNOWN
> Impala Version: impalad version 3.1.0-SNAPSHOT RELEASE ()
> Baseline Impala Version: impalad version 3.1.0-SNAPSHOT RELEASE (2018-07-27)
> +----------+-----------------------+---------+------------+------------+----------------+
> | Workload | File Format | Avg (s) | Delta(Avg) | GeoMean(s) | Delta(GeoMean) |
> +----------+-----------------------+---------+------------+------------+----------------+
> | TPCH(10) | parquet / none / none | 2.69 | -4.78% | 2.09 | -3.11% |
> +----------+-----------------------+---------+------------+------------+----------------+
> +----------+----------+-----------------------+--------+-------------+------------+------------+----------------+-------------+-------+
> | Workload | Query | File Format | Avg(s) | Base Avg(s) | Delta(Avg) | StdDev(%) | Base StdDev(%) | Num Clients | Iters |
> +----------+----------+-----------------------+--------+-------------+------------+------------+----------------+-------------+-------+
> | TPCH(10) | TPCH-Q22 | parquet / none / none | 0.94 | 0.93 | +0.75% | 3.37% | 2.84% | 1 | 30 |
> | TPCH(10) | TPCH-Q13 | parquet / none / none | 3.32 | 3.32 | +0.13% | 1.74% | 2.09% | 1 | 30 |
> | TPCH(10) | TPCH-Q11 | parquet / none / none | 0.99 | 0.99 | -0.02% | 3.74% | 3.16% | 1 | 30 |
> | TPCH(10) | TPCH-Q5 | parquet / none / none | 2.30 | 2.33 | -0.96% | 2.15% | 2.45% | 1 | 30 |
> | TPCH(10) | TPCH-Q2 | parquet / none / none | 1.55 | 1.57 | -1.45% | 1.65% | 1.49% | 1 | 30 |
> | TPCH(10) | TPCH-Q8 | parquet / none / none | 2.89 | 2.93 | -1.51% | 2.69% | 1.34% | 1 | 30 |
> | TPCH(10) | TPCH-Q9 | parquet / none / none | 5.96 | 6.06 | -1.63% | 1.34% | 1.82% | 1 | 30 |
> | TPCH(10) | TPCH-Q20 | parquet / none / none | 1.58 | 1.61 | -1.85% | 2.28% | 2.16% | 1 | 30 |
> | TPCH(10) | TPCH-Q16 | parquet / none / none | 1.18 | 1.21 | -2.11% | 3.68% | 4.72% | 1 | 30 |
> | TPCH(10) | TPCH-Q3 | parquet / none / none | 2.13 | 2.18 | -2.31% | 2.09% | 1.92% | 1 | 30 |
> | TPCH(10) | TPCH-Q15 | parquet / none / none | 1.86 | 1.90 | -2.52% | 2.06% | 2.22% | 1 | 30 |
> | TPCH(10) | TPCH-Q17 | parquet / none / none | 1.85 | 1.90 | -2.86% | 10.00% | 8.02% | 1 | 30 |
> | TPCH(10) | TPCH-Q10 | parquet / none / none | 2.58 | 2.66 | -2.93% | 1.68% | 6.49% | 1 | 30 |
> | TPCH(10) | TPCH-Q14 | parquet / none / none | 1.37 | 1.42 | -3.22% | 3.35% | 6.24% | 1 | 30 |
> | TPCH(10) | TPCH-Q18 | parquet / none / none | 4.99 | 5.17 | -3.38% | 1.75% | 3.82% | 1 | 30 |
> | TPCH(10) | TPCH-Q6 | parquet / none / none | 0.66 | 0.69 | -3.73% | 5.04% | 4.12% | 1 | 30 |
> | TPCH(10) | TPCH-Q4 | parquet / none / none | 1.07 | 1.12 | -3.97% | 1.79% | 2.85% | 1 | 30 |
> | TPCH(10) | TPCH-Q1 | parquet / none / none | 2.29 | 2.39 | -4.34% | 2.70% | 3.43% | 1 | 30 |
> | TPCH(10) | TPCH-Q7 | parquet / none / none | 6.17 | 6.45 | -4.42% | 2.15% | 1.69% | 1 | 30 |
> | TPCH(10) | TPCH-Q19 | parquet / none / none | 1.85 | 1.93 | -4.42% | 2.76% | 2.26% | 1 | 30 |
> | TPCH(10) | TPCH-Q12 | parquet / none / none | 1.32 | 1.42 | -6.75% | 2.55% | 3.56% | 1 | 30 |
> | TPCH(10) | TPCH-Q21 | parquet / none / none | 10.43 | 12.08 | -13.69% | * 14.21% * | * 10.76% * | 1 | 30 |
> +----------+----------+-----------------------+--------+-------------+------------+------------+----------------+-------------+-------+
> {noformat}
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