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https://issues.apache.org/jira/browse/ARROW-6910?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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V Luong updated ARROW-6910:
---------------------------
    Description: 
I realize that when I read up a lot of Parquet files using 
pyarrow.parquet.read_table(...), my program's memory usage becomes very 
bloated, although I don't keep the table objects after converting them to 
Pandas DFs.

You can try this in an interactive Python shell to reproduce this problem:

```{python}
from pyarrow.parquet import read_table

for path in paths_of_a_bunch_of_big_parquet_files:
    read_table(path, use_threads=True, memory_map=False)
    ### note that I'm not assigning the read_table(...) result to anything, so 
I'm not creating any new objects at all

```

After that For loop above, if you view the memory using (e.g. using htop 
program), you'll see that the Python program has taken up a lot of memory. That 
memory is only released when you exit() from Python.

This problem means that my compute jobs using PyArrow currently need to use 
bigger server instances than I think is necessary, which translates to 
significant extra cost.



  was:
I realize that when I read up a lot of Parquet files using 
pyarrow.parquet.read_table(...), my program's memory usage becomes very 
bloated, although I don't keep the table objects after converting them to 
Pandas DFs.

You can try this in an interactive Python shell to reproduce this problem:

```{python}
from pyarrow.parquet import read_table

for path in paths_of_a_bunch_of_big_parquet_files:
    read_table(path, use_threads=True, memory_map=False)
    # note that I'm not assigning the read_table(...) result to anything, so 
I'm not creating any new objects at all

```

After that For loop above, if you view the memory using (e.g. using htop 
program), you'll see that the Python program has taken up a lot of memory. That 
memory is only released when you exit() from Python.

This problem means that my compute jobs using PyArrow currently need to use 
bigger server instances than I think is necessary, which translates to 
significant extra cost.




> pyarrow.parquet.read_table(...) takes up lots of memory which is not released 
> until program exits
> -------------------------------------------------------------------------------------------------
>
>                 Key: ARROW-6910
>                 URL: https://issues.apache.org/jira/browse/ARROW-6910
>             Project: Apache Arrow
>          Issue Type: Bug
>    Affects Versions: 0.15.0
>            Reporter: V Luong
>            Priority: Critical
>
> I realize that when I read up a lot of Parquet files using 
> pyarrow.parquet.read_table(...), my program's memory usage becomes very 
> bloated, although I don't keep the table objects after converting them to 
> Pandas DFs.
> You can try this in an interactive Python shell to reproduce this problem:
> ```{python}
> from pyarrow.parquet import read_table
> for path in paths_of_a_bunch_of_big_parquet_files:
>     read_table(path, use_threads=True, memory_map=False)
>     ### note that I'm not assigning the read_table(...) result to anything, 
> so I'm not creating any new objects at all
> ```
> After that For loop above, if you view the memory using (e.g. using htop 
> program), you'll see that the Python program has taken up a lot of memory. 
> That memory is only released when you exit() from Python.
> This problem means that my compute jobs using PyArrow currently need to use 
> bigger server instances than I think is necessary, which translates to 
> significant extra cost.



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