46

I want to make a function that imports data in different numbers of batches depending on how much RAM is available on someones system. But how can I find the amount of available RAM in R? I can use memory.size() but that only works for Windows.

Sacha Epskamp
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    You are not going to implement one method to do this. Your going to have to detect the platform then use different methods. – Security Hound Jun 23 '11 at 16:16
  • *"If you have to ask for the price, you cannot afford it."* This looks the wrong approach as memory and resource management is handled by the operating system. As Ramhound said, your approach will become platform-dependent. – Dirk Eddelbuettel Jun 23 '11 at 16:24
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    The idea is to get a crude value that works somewhat as a default. For example, 1 batch with 12gb, 2 with 6gb, etcetera. Platform can be found with `Sys.info()` so platform dependent approach should be possible right? – Sacha Epskamp Jun 23 '11 at 16:30

3 Answers3

45

Given the warnings concerning platform-dependency discussed in the earlier comment, you could for example parse /proc/meminfo on Linux:

$ grep MemFree /proc/meminfo 
MemFree:          573660 kB
$ awk '/MemFree/ {print $2}' /proc/meminfo 
565464

You could try the second approach via system(..., intern=TRUE), or even via a pipe connection.

Edit some 5+ years later: In R, and just following what the previous paragraph hinted at:

R> memfree <- as.numeric(system("awk '/MemFree/ {print $2}' /proc/meminfo", 
+                               intern=TRUE))
R> memfree
[1] 3342480
R>
Dirk Eddelbuettel
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    I recommend to use `gc()` before calling this function to get the true amount of available memory. – F. Privé May 01 '17 at 09:00
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    Is the output unit bytes? R in windows usually specifies – QuishSwash Sep 14 '17 at 07:39
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    for those that prefer copy-pasteable code: `as.numeric(system("awk '/MemFree/ {print $2}' /proc/meminfo", intern=TRUE))` – MichaelChirico Dec 11 '17 at 02:18
  • This is not allowed by CRAN. – xiaodai Jan 27 '20 at 01:38
  • @xiaodai do you know why? I have heard cran doesn't like `system()` calls, but I don't believe there's any complete ban. I think cran libraries need to work across all of windows/osx/unix/linux, perhaps this command stumbles on some platform (I don't know that for sure, just trying to guess why it would be denied). – stevec Apr 17 '20 at 07:28
  • I don't know why but my package got taken down cos I used it. So don't use it in a package. – xiaodai Apr 17 '20 at 09:52
  • @F.Privé How does `gc()` be useful in this context? Should the info be gathered from `Ncells` or `Vcells` output? – Prradep Oct 29 '20 at 10:26
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    @Prradep It is useful because it gets rid of all the things that can be cleaned up to free some memory. – F. Privé Oct 29 '20 at 14:57
  • Yes, I understand that. How to infer about the RAM availability from this output? – Prradep Oct 30 '20 at 12:07
9

Now you can do that with benchmarkme::get_ram function.

https://cran.r-project.org/web/packages/benchmarkme/benchmarkme.pdf

user5029763
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3

I would recommend using memuse::Sys.meminfo().

F. Privé
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