[Rd] Speed-up/Cache loadNamespace()

[Serguei Sokol]

Le 20/07/2020 à 10:15, Abby Spurdle a écrit :
> It's possible to run R (or a c parent process) as a background process
> via a named pipe, and then write script files to the named pipe.
> However, the details depend on what shell you use.
>
> The last time I tried (which was a long time ago), I created a small c
> program to run R, read from the named pipe from within c, then wrote
> it's contents to R's standard in.
>
> It might be possible to do it without the c program.
> Haven't checked.
For testing purposes, you can do:

- in a shell 1:
  mkfifo rpipe
  exec 3>rpipe # without this trick, Rscript will end after the first 
"echo" hereafter or at the end of your first script.

- in a shell 2:
  Rscript rfifo

- in a shell 3:
  echo "print('hello')" > rpipe
  echo "print('hello again')" > rpipe

Then in the shell 2, you will see the output:
[1] "hello"
[1] "hello again"
etc.

If your R scripts contain "stop()" or "q('yes')" or any other error, it 
will end the Rscript process. Kind of watch-dog can be set for automatic 
relaunching if needed. Another way to stop the Rscript process is to 
kill the "exec 3>rpipe" one. You can find its PID with "fuser rpipe"

Best,
Serguei.

>
>
> On Mon, Jul 20, 2020 at 3:50 AM Mario Annau <mario.annau using gmail.com> wrote:
>> Dear all,
>>
>> in our current setting we have our packages stored on a (rather slow)
>> network drive and need to invoke short R scripts (using RScript) in a
>> timely manner. Most of the script's runtime is spent with package loading
>> using library() (or loadNamespace to be precise).
>>
>> Is there a way to cache the package namespaces as listed in
>> loadedNamespaces() and load them into memory before the script is executed?
>>
>> My first simplistic attempt was to serialize the environment output
>> from loadNamespace() to a file and load it before the script is started.
>> However, loading the object automatically also loads all the referenced
>> namespaces (from the slow network share) which is undesirable for this use
>> case.
>>
>> Cheers,
>> Mario
>>
>>          [[alternative HTML version deleted]]
>>
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Serguei Sokol
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