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Posted to jira@arrow.apache.org by "Dror Speiser (Jira)" <ji...@apache.org> on 2021/02/24 01:52:03 UTC
[jira] [Commented] (ARROW-10308) [Python] read_csv from python is
slow on some work loads
[ https://issues.apache.org/jira/browse/ARROW-10308?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17289489#comment-17289489 ]
Dror Speiser commented on ARROW-10308:
--------------------------------------
How about I run a benchmark of multiple file sizes, compositions, and block
sizes, on a few types of machines on AWS (from tiny to some xlarge)?
We might get lucky and there's a simple default that increases speed all
around.
> [Python] read_csv from python is slow on some work loads
> --------------------------------------------------------
>
> Key: ARROW-10308
> URL: https://issues.apache.org/jira/browse/ARROW-10308
> Project: Apache Arrow
> Issue Type: Bug
> Components: C++, Python
> Affects Versions: 1.0.1
> Environment: Machine: Azure, 48 vcpus, 384GiB ram
> OS: Ubuntu 18.04
> Dockerfile and script: attached, or here: https://github.com/drorspei/arrow-csv-benchmark
> Reporter: Dror Speiser
> Priority: Minor
> Labels: csv, performance
> Attachments: Dockerfile, arrow-csv-benchmark-plot.png, arrow-csv-benchmark-times.csv, benchmark-csv.py, profile1.svg, profile2.svg, profile3.svg, profile4.svg
>
>
> Hi!
> I've noticed that `pyarrow.csv.read_csv` can be slow on real workloads, processing data around 0.5GiB/s. "Real workloads" means many string, float, and all-null columns, and large file size (5-10GiB), though the file size didn't matter to much.
> Moreover, profiling a little a bit with py-spy, it seems that maybe 30-50% of the time is spent on shared pointer lock mechanisms (though I'm not sure if this is to be trusted). I've attached the dumps in svg format.
> I've also attached a script and a Dockerfile to run a benchmark, which reproduces the speeds I see. Building the docker image and running it on a large Azure machine, I get speeds around 0.3-1.0 GiB/s, and it's mostly around 0.5GiB/s.
> This is all also available here: https://github.com/drorspei/arrow-csv-benchmark
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