use all threads by default

[waynelapierre]

Why not make the data.table package use all threads by default?

[jangorecki]

@waynelapierre if you look through the issues you will probably find the reason.

[mattdowle]

But, @jangorecki, it might be hard to search for! I tried a few google searches and I didn't come up with anything that returned the following.

See new feature 3 in v1.12.2 (Apr 2019) :

So if you prefer to use all logical CPUs by default, on servers for example, just set environment variable R_DATATABLE_NUM_PROCS_PERCENT to 100%. Depending on the task, you'll need to experiment what works best for your data and your machine.

[jangorecki]

@waynelapierre Please subscribe to h2oai/db-benchmark#202 for more precise information about threads vs timing performance.