[jira] [Closed] (ARROW-5993) [Python] Reading a dictionary column from Parquet results in disproportionate memory usage

["Wes McKinney (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-5993?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Wes McKinney closed ARROW-5993.
-------------------------------
    Resolution: Duplicate

I confirmed that this is ARROW-6060. On master peak memory use reading _the entire file_ is 85MB. In 0.14.1 it's a little under 6GB. This code can be used to reproduce

{code}
import pandas as pd
from pandas.util.testing import rands

import pyarrow as pa
import pyarrow.parquet as pq

import gc
class memory_use:
    
    def __init__(self):
        self.start_use = pa.total_allocated_bytes()        
        self.pool = pa.default_memory_pool()
        self.start_peak_use = self.pool.max_memory()
        
    def __enter__(self):
        return
    
    def __exit__(self, type, value, traceback):
        gc.collect()
        print("Change in memory use: {}"
              .format(pa.total_allocated_bytes() - self.start_use))
        print("Change in peak use: {}"
              .format(self.pool.max_memory() - self.start_peak_use))

with memory_use():
    table = pq.read_table('/home/wesm/Downloads/demofile.parquet')        
{code}

> [Python] Reading a dictionary column from Parquet results in disproportionate memory usage
> ------------------------------------------------------------------------------------------
>
>                 Key: ARROW-5993
>                 URL: https://issues.apache.org/jira/browse/ARROW-5993
>             Project: Apache Arrow
>          Issue Type: Bug
>          Components: Python
>    Affects Versions: 0.14.0
>            Reporter: Daniel Haviv
>            Assignee: Wes McKinney
>            Priority: Major
>              Labels: memory, parquet
>             Fix For: 0.15.0
>
>
> I'm using pyarrow to read a 40MB parquet file.
> When reading all of the columns besides the "body" columns, the process peaks at 170MB.
> Reading only the "body" column results in over 6GB of memory used.
> I made the file publicly accessible: s3://dhavivresearch/pyarrow/demofile.parquet
>  
>  



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