getDTthreads not limiting threads on CRAN debian server

[sritchie73]

One of the packages I have developed (ukbnmr) uses data.table and has recently run afoul of CRAN's new checks on CPU usage, which appears to have been caused in part by data.table spawning >2 threads in some of the example code.

After some discussion on the R-package-devel mailing list, I managed to address the CRAN NOTE by explicitly running setDTthreads(1) when running the examples.

The root cause of the problem seems to be a misconfiguration of the CRAN debian server, which may be missing the relevant environment variable that tells getDTthreads() to not use all available CPUs.

I wanted to draw your attention to this, as this is may potentially cause problems for other packages using data.table as a dependency.

The relevant R-package-devel thread is here: https://stat.ethz.ch/pipermail/r-package-devel/2023q3/009454.html

[sritchie73]

Duplicate of #5658