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https://issues.apache.org/jira/browse/ARROW-15730?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17496175#comment-17496175
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Christian commented on ARROW-15730:
-----------------------------------
As one final test I wrote the arrow file in 4 different ways:
c("default", "lz4", "uncompressed", "zstd") %>% walk(~{
log_info(.x)
write_feather(
testdf,
glue('C:/Temp/df_test_\{.x}.arrow'),
compression = .x
)
})
It seems that only when writing it uncompressed it does not have the memory
issue - then it behaves as expected:
* the memory gets freed up after deletion
* the max memory usage is never bigger than the file size (or object size in R)
* the below holds as well.
Allocator mimalloc
Current 0 bytes
Max 0 bytes
Does this make sense to anyone? Is this a bug or is this expected behavior in
Windows?
As said in Linux I don't have that issue (even though the max memory usage
jumps up to twice the object size during reading, it is being freed up again).
> [R] Memory usage in R blows up
> ------------------------------
>
> Key: ARROW-15730
> URL: https://issues.apache.org/jira/browse/ARROW-15730
> Project: Apache Arrow
> Issue Type: Bug
> Components: R
> Reporter: Christian
> Priority: Major
> Fix For: 6.0.1
>
> Attachments: image-2022-02-19-09-05-32-278.png
>
>
> Hi,
> I'm trying to load a ~10gb arrow file into R (under Windows)
> _(The file is generated in the 6.0.1 arrow version under Linux)._
> For whatever reason the memory usage blows up to ~110-120gb (in a fresh and
> empty R instance).
> The weird thing is that when deleting the object again and running a gc() the
> memory usage goes down to 90gb only. The delta of ~20-30gb is what I would
> have expected the dataframe to use up in memory (and that's also approx. what
> was used - in total during the load - when running the old arrow version of
> 0.15.1. And it is also what R shows me when just printing the object size.)
> The commands I'm running are simply:
> options(arrow.use_threads=FALSE);
> arrow::set_cpu_count(1); # need this - otherwise it freezes under windows
> arrow::read_arrow('file.arrow5')
> Is arrow reserving some resources in the background and not giving them up
> again? Are there some settings I need to change for this?
> Is this something that is known and fixed in a newer version?
> *Note* that this doesn't happen in Linux. There all the resources are freed
> up when calling the gc() function - not sure if it matters but there I also
> don't need to set the cpu count to 1.
> Any help would be appreciated.
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