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https://issues.apache.org/jira/browse/ARROW-7043?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16966785#comment-16966785
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Wes McKinney commented on ARROW-7043:
-------------------------------------
The jemalloc changes in 0.15.1 could be a factor here
> [Python] pyarrow.csv.read_csv, memory consumed much larger than raw
> pandas.read_csv
> -----------------------------------------------------------------------------------
>
> Key: ARROW-7043
> URL: https://issues.apache.org/jira/browse/ARROW-7043
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
> Affects Versions: 0.15.0
> Reporter: taotao li
> Priority: Major
>
> Hi, thanks great for building Arrow firstly, I find this project from wes's
> post : [https://wesmckinney.com/blog/apache-arrow-pandas-internals/]
> his ambition on building arrow for fixing problems in pandas really attract
> my eyes.
> bellow is my problems:
> background:
> * Our team's analytic work deeply rely on pandas, we often read large csv
> files into memory and do kinds of analytic work.
> * We have faced problems which mentioned in wes's post, espcially `pandas
> rule of thumb: have 5 to 10 times as much RAM as the size of your dataset`
> * We are looking for some technics which can help us on load our csv(or
> other format, like msgpack, parquet, or something else), using as little as
> memory.
>
> experiment:
> * luckily I find arrow, and I did a simple test.
> * input file: a 1.5GB csv file, around 6 million records, 15 columns;
> * using pandas bellow, which will consume about *1GB memory*,
> *
> {code:java}
> import pandas as pd
> df = pd.read_csv(filename){code}
> * using pyarrow bellow, which will consume about *3.6GB memory,* which
> really makes me confused.
> *
> {code:java}
> import pyarrow
> import pyarrow.csv
> table = pyarrow.csv.read_csv(filename){code}
>
> problems:
> * why pyarrow will need so much memory for reading just 1.5GB csv data, it
> really disappoints me.
> * and when pyarrow is reading the file, my 8 Core CPU is full used.
>
> environments:
> * ubuntu 16
> * python 3.5, ipython 6.5
> * pandas, 0.20
> * pyarrow, 0.15
> * server 8 core, 16 GB
>
> Test File:
> *
> [https://drive.google.com/file/d/1WmUd_NJUIES58bO8mDNd77nf2JVsEu_r/view?usp=sharing]
>
>
>
> great thanks again.
> if needed, I can upload my 1.5GB file later.
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