>>>>> GILLIBERT, Andre
>>>>> on Tue, 24 Aug 2021 09:49:52 +0000 writes:
> RConnection is a pointer to a Rconn structure. The Rconn
> structure must be allocated independently (e.g. by
> malloc() in R_new_custom_connection). Therefore,
> increasing NCONNECTION to 1024 should only use 8
> kilobytes on 64-bits platforms and 4 kilobytes on 32
> bits platforms.
You are right indeed, and I was wrong.
> Ideally, it should be dynamically allocated : either as
> a linked list or as a dynamic array
> (malloc/realloc). However, a simple change of
> NCONNECTION to 1024 should be enough for most uses.
There is one important other problem I've been made aware
(similarly to the number of open DLL libraries, an issue 1-2
years ago) :
The OS itself has limits on the number of open files
(yes, I know that there are other connections than files) and
these limits may quite differ from platform to platform.
On my Linux laptop, in a shell, I see
$ ulimit -n
1024
which is barely conformant with your proposed 1024 NCONNECTION.
Now if NCONNCECTION is larger than the max allowed number of
open files and if R opens more files than the OS allowed, the
user may get quite unpleasant behavior, e.g. R being terminated brutally
(or behaving crazily) without good R-level warning / error messages.
It's also not at all sufficient to check for the open files
limit at compile time, but rather at R process startup time
So this may need considerably more work than you / we have
hoped, and it's probably hard to find a safe number that is
considerably larger than 128 and less than the smallest of all
non-crazy platforms' {number of open files limit}.
> Sincerely
> Andr� GILLIBERT
[............]
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
